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Double minutes ( DMs ) are small fragments of extrachromosomal DNA , which have been observed in a large number of human tumors including breast, lung, ovary, colon, and most notably, neuroblastoma . They are a manifestation of gene amplification as a result of chromothripsis , [ 1 ] during the development of tumors, which give the cells selective advantages for growth and survival. This selective advantage is as a result of double minutes frequently harboring amplified oncogenes and genes involved in drug resistance . DMs, like actual chromosomes , are composed of chromatin and replicate in the nucleus of the cell during cell division . Unlike typical chromosomes, they are composed of circular fragments of DNA , up to only a few million base pairs in size, and contain no centromere or telomere . Further to this, they often lack key regulatory elements , allowing genes to be constitutively expressed . The term ecDNA may be used to refer to DMs in a more general manner. The term Double Minute originates from the visualization of these features under microscope; double because the dots were found in pairs, and minute because they were minuscule.
The most commonly proposed mechanism for DM formation is through chromothripsis, where up to hundreds of genomic arrangements occur in a single catastrophic event, and chromosome fragments which are not reintegrated join to create DMs. [ 1 ] Specific models of DM formation other than chromothripsis have also been suggested. In the “deletion-plus-episome” model, also known as the “episome model,” DNA segments are excised from an intact chromosome, circularized, then amplified as DMs by mutual recombination . [ 2 ] The “translocation-excision-deletion-amplification” model supports that during a translocation event, DMs are formed from the breakpoint region, in the process deleting the genes that are amplified from the chromosome. [ 3 ] Another suggested mechanism is a multi-step evolutionary process, shown in the GLC1 cell line, in which a series of chromosomal mutation events within amplicons create subpopulations of DMs. [ 4 ] Aside from these models, several studies suggest other processes for DM formation such as through the breakdown of a homogeneously staining region (HSR) following cell fusion, [ 5 ] through chromosomal breaks due to hypoxia induced activation of fragile sites , [ 6 ] or reduction in the level of DNA methylation . [ 7 ]
DM formation is particularly important for its role in gene amplification. In addition to their ability to harbor genes, DMs are autonomously replicating, facilitating further gene amplification. [ 2 ] The circular and less compressed structure of DMs also allows for an increased transcriptional level by having a more open conformation that is more accessible to transcriptional elements and contact with enhancers. [ 8 ] The “breakage-fusion-bridge” cycle , which describes an event where telomere loss causes the repeated joining and pulling apart of sister chromatids as cell division occurs, is a popular model to explain the amplification of intrachromosomal genes. While this process does not directly produce DMs, it has been suggested as an early step in their formation, so may also contribute to gene amplification by DMs. [ 9 ]
The presence of DMs in tumor cells is a somewhat rare occurrence, but certain cancers have been found to have a high incidence rate. An extensive cancer database search found that about 1.4% of all cases are positive for DMs, and out of cancer types, neuroblastoma has the highest frequency of DMs at 31.7%. [ 10 ] The amplification of specific genes that support the growth of tumor cells, such as oncogenes or drug-resistant genes, is critical to the cell adoption of malignancy . [ 11 ] Due to their role in gene amplification, the presence of DMs can therefore be a factor in acceleration of tumor growth. One example of this is DM facilitated amplification of the MYC gene in patients with acute myeloid leukemia , an event which is correlated with poor survival. [ 12 ] Inducing the loss of extrachromosomally amplified genes in human tumor cells has been shown to reduce tumorigenicity, so the elimination of DMs or other ecDNA carrying oncogenes is one suggested avenue of cancer treatment research. [ 13 ]
Aside from gene amplification, DMs play a role in cancer through driving tumor evolution and treatment resistance. While DMs lack the centromeres and telomeres usually essential for subdividing chromosome material during cell division, they can segregate to the daughter cell nucleus by associating with the telomeric ends of mitotic chromosomes. [ 14 ] This process results in varied partitioning, and the unequal division in the number of DMs passed to offspring cells increases tumor heterogeneity , driving tumor evolution and increasing the chance of tumor cells acquiring a selective advantage. [ 15 ] Amplified genes, in addition to residing in DMs, can also be located in the chromosomal HSRs. Inter-conversion between DMs and HSRs has been suggested as a mechanism for chemotherapy resistance, as oncogenes targeted by drug treatment are selectively eliminated from extrachromosomal DNA but reemerge after drug withdrawal. [ 16 ]
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https://en.wikipedia.org/wiki/Double_minute
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The Bidhan Chandra Roy Award is an award instituted in 1962 in memory of Dr. B. C. Roy by the Medical Council of India . It is presented by the President of India in New Delhi every year on July 1, National Doctors' Day . It is also the highest honour that can be achieved by a doctor in India.
The award is given annually in each of the following categories:
It was first awarded in 1972 to Dr M.P Mehrey of Sitapur Eye Hospital, Sitapur(also referred to as the Regional Institute of Ophthalmology), by V. V. Giri , the then President of India .
Source: [ 64 ]
Eminent Medical Person:
Eminent Medical Teacher:
Best talents in encouraging the development of specialities in different branches in Medicine:
Outstanding services in the field of Sociomedical Relief:
Source: [ 64 ]
Eminent Medical Person:
Eminent Medical Teacher:
Best talents in encouraging the development of specialities in different branches in Medicine:
Outstanding service in the field of Socio Medical Relief:
Aid or Assistance to Research Project:
Source: [ 64 ]
Eminent Medical Person:
Eminent Person - Literature:
Eminent Medical Teacher:
Best Talents in Encouraging the Development of Specialties in Different Branches in Medicines:
Outstanding Service in the field of Socio Medical Relief:
Aid or Assistance to Research Project:
Eminent Medical Person:
Outstanding service in the field of socio medical relief
Best talents in encouraging the development of specialties in different branches in Medicine
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https://en.wikipedia.org/wiki/Dr._B._C._Roy_Award
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Dr. Lucy Dupuy Montz House is a historical building in Warsaw, Kentucky that was the location of Lucy Dupuy Montz home residence and dental practice. Montz was Kentucky's first woman dentist. [ 2 ] In 1978, the building was listed on the National Register of Historic Places . [ 3 ]
Warsaw Historic District (Warsaw, Kentucky)
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https://en.wikipedia.org/wiki/Dr._Lucy_Dupuy_Montz_House
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The Dr. Paul Janssen Award for Biomedical Research is given annually by Johnson & Johnson to honor the work of an active scientist in academia, industry or a scientific institute in the field of biomedical research. It was established in 2004 and perpetuates the memory of Paul Janssen , the founder of Janssen Pharmaceutica , a Johnson & Johnson subsidiary. [ 1 ]
The Dr. Paul Janssen Award includes a $200,000 prize and acknowledges the work of an individual who has made a significant, transformational contribution toward the improvement of human health. [ 2 ]
Johnson & Johnson created the award in 2004 with the following goals:
Known to his colleagues as “Dr. Paul,” Janssen was the founder of Janssen Pharmaceutica, N.V., a pharmaceutical research laboratory based in Beerse , Belgium , and a physician-scientist who helped save millions of lives through his contribution to the discovery and development of more than 80 medicines. His work was responsible for many breakthroughs in several fields of disease, including pain management, psychiatry , infectious disease and gastroenterology . In addition, he has more than 100 patents to his name.
Source: Jannsen
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https://en.wikipedia.org/wiki/Dr._Paul_Janssen_Award_for_Biomedical_Research
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DrSmile is a dentistry brand by German startup Urban Technology GmbH based in Berlin .
DrSmile was founded in 2016 in Berlin by Jens Urbaniak and Christopher von Wedemeyer. Urbaniak worked for Rocket Internet and is a co-founder of Go Butler, and von Wedemeyer previously worked as an investment banking analyst. [ 1 ] In July 2020, it was announced that Swiss dental implant manufacturer Straumann bought a majority stake in the start-up for 110 million CHF and secured an option on the remaining shares. [ 2 ] In May 2022, DrSmile acquired the start-up PlusDental for €131 million. [ 3 ] In August 2024 Straumann announced the sale of its DrSmile aligner business. [ 4 ] Straumann said it had signed an agreement to sell DrSmile to Barcelona-based clear aligner provider Impress Group.
DrSmile has locations in Berlin, Düsseldorf , Frankfurt , Hamburg , Cologne , Munich , Nuremberg , Stuttgart and Hannover . [ 5 ] The company works with a partner network of dentists and orthodontists . [ 1 ]
DrSmile focuses on aesthetic dental treatments with invisible aligners that correct minor and medium malpositions of teeth. [ 1 ] [ 6 ] Aligners are produced using 3D printer technology. [ 7 ] [ 8 ] [ 9 ]
DrSmile, along with similar companies, has faced criticism from some dental professionals due to concerns about the lack of medical consultation and examination. [ 10 ] In particular, criticism has been directed at concepts where patients take impressions of their teeth at home without direct supervision from a dentist. While DrSmile asserts that it collaborates with dentists and orthodontists, and distances itself from procedures that do not involve professional medical consultation, there have been legal challenges regarding the thoroughness of the examination process. [ 11 ] [ 7 ] In 2019, a German court ruled that certain dental standards were not met. [ 12 ] In March 2024, the company was fined PLN 2,782,817 for actions violating the collective interests of consumers by the Polish Office of Competition and Consumer Protection. Another fine of PLN 674,622 was imposed for using a prohibited contractual clause, but this decision is not yet final. [ 13 ]
Besides controversy about the lack of medical consultation and examination, DrSmile has a significant number of negative reviews. [ 14 ] These show a lot of issues with aggressive sales techniques and lack of communications. Customers of DrSmile enter into a contract with DZK Deutsche Zahnklinik GmbH, which appears to be a mailbox clinic. [ 15 ] The Ordnungsamt (Public Office) has started an investigation.
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https://en.wikipedia.org/wiki/DrSmile
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The Dravet Syndrome Foundation (DSF) is a volunteer -run, non-profit organization based in the United States. The mission of the foundation is to raise research funds for Dravet's syndrome and related epilepsies , while providing support to affected individuals and families. The Dravet Syndrome Foundation is listed as a research and support organization on National Organization of Rare Diseases 's (NORD) database. [ 1 ]
The Dravet Syndrome Foundation was founded by parents with the purpose of expediting research to find a cure and better treatments for their afflicted children. [ 2 ] It was established in the state of Connecticut and was designated a tax-exempt public charity in the United States in September 2009 by the Internal Revenue Service under Section 501(c)(3) .
The Dravet Syndrome Foundation focuses its work in four areas: research grants ; Research Roundtable; International Ion Channel Epilepsy Patient Registry (IICEPR); and the International Patient Assistance Grant (PAG) Program.
Grants are offered for research projects and postdoctoral fellowships directly related to Dravet syndrome and associated epilepsies. These grants fund initial research hypotheses that have not been fully explored. The results extracted from this type of research will help bring untested research to the point that it can qualify for larger governmental funding. Research applications are judged principally on novelty of the hypotheses, innovative approaches with a direct relevance and application to Dravet syndrome and related conditions, scientific quality, strength of approach, and likelihood of success.
This annual meeting allows researchers, geneticists , neurologists , and other professionals with a strong interest in Dravet syndrome and related epilepsies to establish a "research roadmap". By allowing this consortium of specialists to establish a plan, the Dravet Syndrome Foundation can facilitate the development and implementation of better treatments by funding research projects that address the critical challenges of this syndrome and which will offer the most promising breakthroughs at the fastest pace possible. This meeting takes place each year just prior to the commencement of the American Epilepsy Society (AES) Conference.
This three-day event is designed to unite all groups committed to improving the lives of those with Dravet syndrome – including families, caregivers, clinicians, researchers and professionals in the pharmaceutical industry. There are speaker presentations on the latest advances in research as well as sessions with up to date information impacting patient care. This event allows the opportunity to foster new relationships and collaborations, both for families and professionals. It is held on even-numbered years at locations across the U.S.
This registry (co-funded with ICE Epilepsy Alliance) is owned by University of Michigan Neurology Department and Miami Children's Hospital Brain Institute but is available to all interested researchers. It will collect basic information and genetic test results of individuals with Dravet syndrome and related epilepsies worldwide. The establishment of this registry will expedite future clinical trials and will serve to improve communication of ideas amongst interested researchers, as well as assure rapid distribution of any new information that may benefit patients and their families.
This program offers grants to patients with Dravet syndrome and associated epilepsies for necessary medical equipment needs associated with these conditions that are not covered through private insurance or other assistance programs. [ 3 ]
The Dravet Syndrome Foundation’s scientific advisory board (SAB) oversees the organization’s research activities. They review and approve all research grant applications and meet annually with other interested researchers and scientists to discuss innovative and promising research in the field of Dravet syndrome and associated epilepsies at DSF’s Research Roundtable.
In addition to private donations, private fundraising events, corporate sponsorships and grants, the Dravet Syndrome Foundation produces annual fundraising events.
City Bash is the Dravet Syndrome Foundation's annual signature event where money is raised for research while honoring a professional who has gone above and beyond in the field of Dravet syndrome and related epilepsies. Steps Toward A Cure consists of family-friendly fundraising walks across the U.S., organized by families. Race for Research allows athletes to participate in an event of their choosing, while raising funds for DSF.
In 2011, a group of parents formed a delegation of the Dravet Syndrome Foundation in Spain (DSF Spain). Both organizations work closely together, but have separate boards of directors and scientific advisory boards. DSF Spain announced its first research grant award in summer 2011.
The Dravet Syndrome Foundation works with the following like-minded organizations to assure rapid distribution of information and to avoid duplication of efforts and research dollars.
The Dravet Syndrome Foundation (DSF) was established in 2009 to increase research for Dravet syndrome. Their strategy has been to invest in researchers with $50,000–150,000 grants for 1–2 year projects, with the hope that they will use those preliminary studies to apply for larger NIH grants, establishing their place in the field of epilepsy research and DS in particular.
Since its inception in 2009, DSF has awarded over $3.6M in research grants and postdoctoral fellowships.
In the eight years prior to DSF’s founding, from 2002–2009, NIH spent only $6.3 million on projects mentioning Dravet syndrome (DS) or Severe Myoclonic Epilepsy of Infancy (SMEI). Only about 30 studies were published on DS. In the eight years since DSF’s founding, from 2010–2017, NIH spent $44.6 million on projects mentioning DS or SMEI, or seven times the research dollars. Over 300 studies were published on DS. There was an explosion of federal dollars spent on DS between 2010 and 2014, when DSF was first raising awareness and funding in the research world while investing in researchers. Of the 19 researchers DSF invested in through 2015, six of them went on to receive large NIH grants, for a return rate of 32%.
Research awards can be broken down in the following categories for total funding of $3,698,000:
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https://en.wikipedia.org/wiki/Dravet_Syndrome_Foundation
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DreamLab was a volunteer computing Android and iOS app launched in 2015 by Imperial College London and the Vodafone Foundation . [ 1 ] [ 2 ] It was discontinued on 2nd April 2025.
The app currently helps to research cancer , [ 3 ] COVID-19 , new drugs and tropical cyclones. [ 4 ] To do this, DreamLab accesses part of the device's processing power, with the user's consent, while the owner is charging their smartphone , to speed up the calculations of the algorithms from Imperial College London . [ 5 ] [ 1 ] [ 6 ]
The aim of the tropical cyclone project is to prepare for climate change risks. Other projects aim to find existing drugs and food molecules that could help people with COVID-19 and other diseases. The performance of 100,000 smartphones would reach the annual output of all research computers at Imperial College in just three months, with a nightly runtime of six hours. [ 3 ] [ 7 ] [ 8 ]
The app was developed in 2015 by the Garvan Institute of Medical Research in Sydney and the Vodafone Foundation. [ 9 ] [ 10 ] As of May 2020, the project had over 490,000 registered users.
This mobile software article is a stub . You can help Wikipedia by expanding it .
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https://en.wikipedia.org/wiki/DreamLab
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A drop attack is a sudden fall without loss of consciousness . Drop attacks stem from diverse mechanisms, including orthopedic causes (for example, leg weakness and knee instability ), hemodynamic causes (for example, transient vertebrobasilar insufficiency , a type of interruption of blood flow to the brain), and neurologic causes (such as epileptic seizures or unstable vestibular function), among other reasons. Those affected typically experience abrupt leg weakness, sometimes after sudden movement of the head. The weakness may persist for hours.
The term "drop attack", also known as "cryptogenic drop attack" or "La maladie des genoux bleus"; [ 1 ] [ 2 ] [ 3 ] is used to categorize otherwise unexplained falls from a wide variety of causes and is considered ambiguous medical terminology; drop attacks are currently reported much less often than in the past, possibly as a result of better diagnostic precision. [ 4 ] [ 5 ] By definition, drop attacks exclude syncopal falls (fainting) , which involve short loss of consciousness. In neurology , the term "drop attack" is used to describe certain types of seizure which occur in epilepsy . [ 6 ] [ 7 ] Drop attacks that have a vestibular origin within the inner ear may be experienced by some people in the later stages of Ménière's disease (these may be referred to as Tumarkin [drop] attacks, or as Tumarkin's otolithic crisis). [ 8 ] [ 9 ]
Drop attacks often occur in elderly people; with a majority of documented cases occurring in women. [ 10 ] [ 11 ] [ 12 ] [ 13 ] Falls in older adults happen for many reasons, and the goals of health care include preventing any preventable falls and correctly diagnosing any falls that do happen.
This medical symptom article is a stub . You can help Wikipedia by expanding it .
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https://en.wikipedia.org/wiki/Drop_attack
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Drug eluting implants encompass a wide range of bioactive implants that can be placed in or near a tissue to provide a controlled, sustained or on demand release of drug while overcoming barriers associated with traditional oral and intravenous drug administration , such as limited bioavailability , metabolism, and toxicity. [ 1 ] These implants can be used to treat location-specific and surrounding illness and commonly use 3D printing technologies to achieve individualized implants for patients. [ 2 ]
The production of drug eluting implants has grown significantly in the last decade and continues to be an area of research due to their flexible nature that can be utilised for the treatment of a multitude of medical conditions. [ 3 ] These implants can be loaded with a variety of different drug types such as antibiotics , antivirals , chemotherapy , growth factors and anti-inflammatory drugs . [ 4 ]
Drug eluting implants can provide a versatile method of drug delivery that can be personalized and targeted to treat a variety of medical conditions and overcome issues such as drug bioavailability, metabolism and dosage associated with traditional drug delivery systems. [ 5 ]
Drug eluting implants can be used in the management and treatment of a variety of medical conditions. Traditional drug delivery methods have potential disadvantages that have led to the development of different drug delivery techniques across most body systems, many of which can improve treatment efficacy . [ 1 ]
Drug-eluting stents and balloons are a common therapeutic method in the management and treatment of cardiovascular disease that to open and maintain arteries while delivering drug locally to an area of a vessel . [ 1 ] [ 2 ]
Common gynecological implants that elute contraceptive medication can be inserted subcutaneously or into the uterus . Non-invasive drug eluting ring implants that can be inserted into the vagina and release therapeutic doses of contraceptive, anti-inflammatory and antibiotic drugs to increase compliance of contraceptive therapeutics are under development. [ 1 ] [ 6 ]
The treatment of orthopedic conditions has proved to be a large target area for drug eluting implants. Current uses for this method drug delivery include bone and joint implants that can release drugs at the joint replacement sites to prevent infection and anti-inflammatory responses. [ 7 ]
Other potential treatments using this method of drug delivery in orthopedic medicine include drug eluting implants that aid in the regeneration of bone at implantation sites while reducing microbial growth . [ 8 ]
Current treatment for oncological conditions include chemotherapy, radiation and surgery. [ 9 ] Drug eluting implants have shown potential in the treatment of cancer through adjuvant chemotherapy that has shown to suppress tumor formation locally, overcoming side effects associated with systemic chemotherapy treatment and reduce the need for surgical resection of cancerous tumors. [ 10 ]
Intravitreal administration of therapeutic drug doses is commonly done via injection or implant. [ 11 ] Drug eluting contact lenses and implants can deliver targeted and extended doses of drug to the retina without the need for injection. [ 12 ]
Drug eluting sutures can produce a prolonged local release of anaesthetic as well as heal wounds. This has the potential to limit the need for postoperative opioid analgesics that can cause addiction. [ 13 ]
Drug eluting implants are designed to be implanted into location specific tissues and release drug locally. These implants are made using biocompatible materials that will not elicit an immune response. [ 14 ]
The structure of the implant is individualized and designed to conform to the shape of the tissue that is being treated. The implant contains a reservoir that elutes a drug dependent on the mechanism of release. This mechanism be in the form of a matrix coating of the implant or a reservoir within the implant. [ 15 ] Designs aim to provide therapeutic dosage to the target tissue while reducing negative side effects and maximizing efficacy. [ 15 ]
There are a variety of methods used in the manufacturing of drug eluting implants, most of which utilize 3D printing technology. Techniques are dependent on factors such as the condition being managed, the drug being released and the individual patient being treated. [ 5 ]
3D printing involves the production of a 3-dimensional object through the layering of material. There are a variety of 3D printing techniques, all of which come with their own advantages and disadvantages which should be considered when creating an individualized implant. The production of these drug eluting implants through 3D printing is currently being investigated to determine drug delivery properties and efficacy to improve individualized medicinal devices. [ 5 ]
Traditional bio-printing technologies used in the field of biomedical engineering include inkjet-based systems, extrusion-based systems, and laser-assisted systems that can be used to create highly specific and individual implants for patients. [ 4 ]
The most common materials used to create drug eluting implants include highly versatile polymers , ceramics , and metals, all with varying kinetics that can be manipulated to produce the desired drug delivery effect. [ 5 ] [ 16 ]
Polymers and polymer networks are among the most widely used materials in drug eluting implants. These implants are classified as either degradable and able to be broken down and metabolized by the body, or non-degradable which eventually require removal. [ 2 ]
Common degradable polymer materials used in drug eluting implants include poly e-caprolactone (PCL), polylactic-co-glycolic acid (PLGA) and poly-L-lactic acid (PLLA), while non-degradable polymer materials include silicones commonly used in plastic surgery, urethanes and acrylates , and are more likely to be used in the treatment of chronic conditions in which long term implantation is to be expected. [ 2 ]
Polymers can be used to create monolithic drug delivery systems in which a drug is released in a rate-controlled polymer matrix , reservoir drug delivery systems containing a drug-filled core that releases drug in a manner dependent on the surrounding polymer, and hydrogels that can release drugs controlled by a variety of stimuli including ultrasound , temperature, and pH changes. [ 2 ] [ 16 ] [ 17 ]
In relation to biomedical implant manufacturing, the term 'ceramic' can be used to encompass a wide variety of non-metallic substances that can be utilised in drug eluting implants due to their biocompatible properties such as resistance to corrosion and shear , low electrical conductance ability, and high melting temperatures . [ 18 ] [ 19 ]
Ceramic implants can be classified as bio-inert and include materials such as aluminum , zirconia , and certain carbon and silicon derivatives which are not biodegradable. Bioactive ceramic implants are biodegradable substances that include calcium phosphates , and a variety of oxidised minerals that mimic natural bone properties. Ceramic drug eluting implants are therefore commonly used in hard tissue replacement surgeries such as bone. [ 18 ] [ 19 ]
Metals such as titanium are highly biocompatible and therefore commonly used in osteopathic medicine in the manufacturing of artificial joints . These joints are often coated in polymeric, or ceramic material embedded with drugs for prevention of infection and rejection, and to reduce inflammatory responses that are common among joint implants. [ 20 ]
Metals however are susceptible to erosion and infection and lack biological activity. When metals are used as an implant as opposed to a permanent mechanical fixture, problems can arise when contacting associated bone and releasing drug to target tissues such as static stresses that can lead to bone loss at the site of implantation. [ 4 ]
The idea of a drug eluting implant is to overcome many of the obstacles associated with traditional drug therapies, as well as reducing the need for potentially invasive procedures, including those involved in the removal of embedded drug eluting implants. [ 5 ]
The loading of a drug onto a matrix can be either incorporated into the drug at the time of manufacture or performed after the printing of an implant is complete. Drugs integrated at the point of manufacture through blending with polymeric materials are generally able to withstand preparation conditions which can exclude many sensitive drugs from this mechanism. Therefore, loading after manufacture is considered to be an easier method. [ 5 ]
Normally, once drug is loaded into a delivery system, there is no non-invasive way to refill once drug levels in the system are depleted. Developments in drug delivery refilling have shown potential through chemically modified drug-loaded hydrogels that, once in the body, are able to translocate to a specific local drug delivery depot as a non-invasive means of refilling. [ 21 ]
Drug eluting implants aim to improve efficacy of drug delivery by overcoming issues commonly associated with traditional systemic administration of drugs such as metabolism, toxicity, and an inability to maintain a certain concentration of drug in the circulation . To overcome these issues, patients are usually administered higher doses of drugs in a controlled and clinical setting. [ 1 ]
The introduction of a drug eluting implant to a local tissue can provide targeted and sustained dosing of drug and prevent systemic metabolism, a common obstacle seen in orally delivered medications. This can reduce dosage which can in turn reduce treatment cost. Lower drug concentrations delivered via local depots can therefore lower the risk of toxicity as well as increasing compliance and reducing physician/patient burden to manage appropriate drug concentrations. [ 15 ] [ 18 ]
Drug eluting implants also provide an effective mechanism for bypassing the blood-brain barrier , and this method of drug delivery is primarily used in the treatment of glial tumors . [ 15 ]
There are issues that can arise with the local and targeted method of drug eluting implants. [ 1 ] One of the largest obstacles that the field of drug eluting implants faces is the mechanism of drug loading and reloading of non-biodegradable implants. The development of drugs that can travel from systemic circulation to a specific depot could prove a useful way to overcome the need for invasive refilling and re-implantation. [ 15 ] [ 21 ]
Foreign bodies implanted into the body can elicit immune responses . Medically implanted drug eluting devices can induce an inflammatory response as well as being rejected by the body which can cause chronic inflammation . [ 22 ] Anti-inflammatory drugs can be administered alongside the implantation of a drug eluting device to prevent chronic inflammation and systemic immune side effects that this may induce. [ 4 ]
The field of drug eluting implants is expanding to encompass treatment and management methods for a variety of treatments. In the future, possibilities exist to manufacture 'smart' drug eluting implants fitted with sensors that can provide feedback-controlled drug delivery in patients suffering from abnormalities such as diabetes , or for patients that experience seizures and require prophylactic treatment . [ 15 ]
The development of novel drug eluting implant materials and mechanisms has the potential for improving patient safety , comfort, compliance and thus acting on global health challenges such as chronic diseases, infectious and non-infectious diseases, and contraception. [ 14 ]
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https://en.wikipedia.org/wiki/Drug-eluting_implant
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A drug-eluting stent (DES) is a tube made of a mesh-like material used to treat narrowed arteries in medical procedures both mechanically (by providing a supporting scaffold inside the artery) and pharmacologically (by slowly releasing a pharmaceutical compound). A DES is inserted into a narrowed artery using a delivery catheter usually inserted through a larger artery in the groin or wrist. The stent assembly has the DES mechanism attached towards the front of the stent, and usually is composed of the collapsed stent over a collapsed polymeric balloon mechanism, the balloon mechanism is inflated and used to expand the meshed stent once in position. The stent expands, embedding into the occluded artery wall, keeping the artery open, thereby improving blood flow. The mesh design allows for stent expansion and also for new healthy vessel endothelial cells to grow through and around it, securing it in place. [ 1 ] [ 2 ] [ 3 ]
A DES is different from other types of stents in that it has a coating that delivers medication directly into the blood vessel wall. The stent slowly releases a drug to prevent the growth of scar tissue and new obstructive plaque material which caused the original blood vessel stenosis, this clogging of a stent is termed restenosis . A DES is fully integrated with a catheter delivery system and is viewed as one integrated medical device . [ 4 ] [ 5 ] [ 6 ]
DESs are commonly used in the treatment of narrowed arteries in the heart ( coronary artery disease ), but also elsewhere in the body, especially the legs ( peripheral artery disease ). [ 7 ] Over the last three decades, coronary stenting has matured into a primary minimally invasive treatment tool in managing CAD. [ 8 ] Coronary artery stenting is inherently tied to percutaneous coronary intervention (PCI) procedures. PCI is a minimally invasive procedure performed via a catheter (not by open-chest surgery), it is the medical procedure used to place a DES in narrowed coronary arteries. PCI procedures are performed by an interventional cardiologist using fluoroscopic imaging techniques to see the location of the required DES placement. PCI uses larger peripheral arteries in the arms or the legs to thread a catheter/DES device through the arterial system and place the DES in the narrowed coronary artery or arteries. [ 7 ] Multiple stents are often used depending on the degree of blockage and the number of diseased coronary arteries that are being treated. [ 9 ] [ 10 ]
A drug-eluting stent (DES) is a small mesh tube that is placed in the arteries to keep them open in the treatment of vascular disease . The stent slowly releases a drug to block cell proliferation (a biological process of cell growth and division), thus preventing the arterial narrowing ( stenosis ) that can occur after stent implantation. While such stents can be used in various arteries throughout the body, they are commonly placed in the coronary arteries to treat coronary heart disease . [ 11 ] [ 12 ] [ 13 ] [ 14 ] DES products are integrated medical devices and are part of a percutaneous coronary intervention (PCI) delivery system. [ 15 ] [ 16 ] [ 17 ] [ 18 ]
DES is a medical device with several key properties: it functions as a structural scaffold, physically keeping an artery open to ensure blood flow; the device has specific drug delivery features, and the chosen drug is critical for its effectiveness. The drug, the hallmark compenent of the device, is selected for its suitability in inhibiting restenosis and its pharmacokinetics . Apart from the drug, the materials used in the fabrication of the device are also essential and are carefully chosen for their biocompatibility and durability in a biological environment, such as human blood; these materials must also withstand the constant motion of the heart's beat and be suitable for future patient imaging using magnetic resonance imaging (MRI) technologies, which employ high magnetic fields . [ 15 ] [ 16 ] [ 17 ] [ 18 ]
Other components, such as the catheter design, also play significant roles in the device's overall functionality and effectiveness. [ 15 ] [ 16 ] [ 17 ] [ 18 ]
DES are typically composed of metal alloys, most commonly stainless steel or cobalt-chromium , but can also be made of other materials such as platinum-chromium or nickel-titanium . The stent is often coated with a polymer to control the release of drugs. The role of polymers in drug delivery is significant as they regulate the rate at which the drug is released into the surrounding tissue. [ 19 ] [ 20 ] There are also polymer-free stents where the drug is directly coated on the stent or contained in reservoirs within the stent. [ 21 ] [ 22 ] [ 23 ] [ 24 ]
The design of the stent includes struts , which are thin wire structures that make up the stent frame. The strut thickness can influence the stent's performance, with thinner struts generally being associated with lower restenosis rates and reduced thrombosis risk. [ 25 ] [ 26 ] [ 20 ]
Most DES are balloon-expandable, meaning they are mounted on a balloon catheter and expand when the balloon is inflated. [ 27 ] [ 28 ] There are also self-expanding stents, which automatically expand when deployed. The very first stent, introduced in 1986, was of this type. [ 29 ] [ 30 ] [ 31 ] [ 32 ]
The stent tube mesh is initially collapsed onto the catheter—in this collapsed state, it is small enough to be passed though relatively narrow arteries and then expanded in its destination place, pushing firmly to the diseased artery wall. [ 33 ] [ 34 ]
The pharmaceutical compounds that DES emit are antiproliferative agents such as sirolimus , everolimus , zotarolimus , paclitaxel and biolimus . These drugs help prevent the arterial narrowing that can occur after stent implantation. [ 35 ] [ 36 ] [ 37 ] These drugs are also used for other purposes, that involve moderating the immune system or treating cancer. They work by inhibiting cell growth. In DES, they are used in very small amounts and for a short time, and only in the area where the stent is placed. [ 38 ]
There is a distinction between coronary stents and peripheral stents. [ 7 ] While both are used to prevent the narrowing of arteries, coronary stents are specifically for the coronary arteries , while peripheral stents are for any other arteries in the body. [ 39 ] [ 40 ] [ 41 ] Peripheral stents are mostly bare metal ones; some peripheral DES, of the self-expanding type, are used in arteries of the legs. [ 42 ]
Bioresorbable DES are made of materials that can be absorbed by the body over time, potentially reducing potential long-term complications associated with permanent stents. [ 43 ]
Atherosclerosis is a chronic disease that affects the large and medium-sized arteries. It is characterized by the accumulation of calcium, fats (such as cholesterol) and other substances in the innermost layer of the endothelium, a layer of cells that line the interior surface of blood vessels. Atherosclerosis is considered to be the most common form of arteriosclerosis, which refers to the loss of arterial elasticity caused by thickening and stiffening of blood vessels. [ 44 ]
Atherosclerosis can begin as early as childhood with the development of small "fatty streaks" within arteries. These streaks are essentially deposits of fat. Over time, these initial lesions grow larger and become thicker, forming atheromas (atherosclerotic plaques). [ 44 ]
Drug-eluting stents (DESs) are used in the treatment of atherosclerosis in both coronary interventions and peripheral arterial interventions: [ 45 ] [ 46 ]
DESs are used in the management of atherosclerosis in both coronary and peripheral arterial interventions. [ 7 ] They help improve blood flow and reduce the risk of restenosis, thereby improving patient outcomes. The use of DESs is accompanied by appropriate medical therapy and lifestyle modifications to manage atherosclerosis effectively. [ 51 ]
Stenosis of blood vessels refers to the narrowing of the blood vessels, which can restrict blood flow to the organs and tissues. [ 20 ] This condition is often caused by the buildup of fatty deposits in the arteries, a process also called atherosclerosis. [ 55 ]
In the context of stents, stenosis is a significant concern. Stents are inserted into a narrowed artery during a procedure known as angioplasty. The stents help to open up the narrowed artery and improve blood flow. However, over time, the treated artery can close up again, a condition known as restenosis. [ 20 ]
Restenosis, or in-stent restenosis, is a blockage or narrowing that comes back in the portion of the artery previously treated with a stent. [ 20 ] Restenosis tends to happen three to six months after the procedure. [ 20 ] Restenosis is even more likely to occur if a stent would not have been used. [ 20 ]
When restenosis occurs, another procedure may be needed to correct the problem, such as the placement of a DES [ 20 ] [ 55 ] that gradually release a drug compound that suppresses cellular growth, thereby reducing the potential for blockage within the stent area itself. [ 20 ] [ 55 ] This therapy significantly reduces the occurrence of adverse events post-stenting. [ 20 ] [ 55 ]
Technically, a DES in a mesh tube implant devices that is used in angioplasty procedures to treat stenosis of blood vessels and prevent restinosis: the stent, which elutes drugs, is implanted into the blood vessel to help keep the vessel open and improve blood flow. [ 56 ] [ 57 ] [ 58 ] Specifically, drug-eluting stents are used in the treatment of various medical conditions usually at the site of stenotic or occlusive arterial lesions, but one of the primary medical uses is in the treatment of coronary artery disease. [ 59 ] Stents are inserted into narrowed coronary arteries, where the narrowing is primarily caused by atherosclerosis. Stents are then expanded to open up the narrowed artery. Such stents gradually release a drug compound that suppresses cellular growth , into the newly stented area, thereby reducing the potential for blockage within the stent area itself. [ 59 ] Such blockage is termed in-stent restenosis (ISR). This in-stent blockage is most often caused by excessive cell proliferation or thrombi (blood clots). Anticoagulation therapy (blood thinners), has become a standard treatment following the placement of DES. This therapy significantly reduces the occurrence of adverse events post-stenting. [ 60 ] [ 61 ] [ 62 ]
DESs have played a transformative role in the management of coronary artery disease. These stents are tiny, flexible mesh tubes employed during percutaneous coronary intervention (PCI) to address narrowed coronary arteries. What sets them apart is their special coating, which incorporates a drug delivery system that enables controlled release of medication over a specific period, typically within the first 30 to 45 days following implantation. This medication aids in inhibiting the formation of scar tissue within the stent and subsequent re-narrowing of the blood vessel. [ 63 ] [ 64 ]
PCI is a minimally invasive procedure. It involves the placement of a drug-eluting stent (DES) in a coronary artery. This procedure, previously known as angioplasty with a stent, is considered non-surgical as it is performed through a small puncture in a peripheral artery, avoiding the need to open the chest wall. While bleeding from the puncture site was once a concern, advancements in PCI practices have mitigated this issue through the use of pressure bands and arterial closure systems. Modern DES/PCI procedures are generally painless, although some mild discomfort may be experienced. [ 65 ] [ 66 ] [ 67 ] In PCI, multiple DES are sometimes implanted within a single patient; the decision to use multiple stents is typically contingent on the extent of the coronary artery disease present and the number of diseased coronary arteries that require treatment. [ 9 ] [ 10 ]
DESs have emerged as the primary therapeutic approach for managing symptomatic peripheral arterial disease (PAD). These specialized stents are now widely utilized in the treatment of peripheral arterial occlusive disease (PAOD), a condition that shares similarities with coronary artery disease but affects the peripheral arteries. By deploying DESs, healthcare professionals can effectively address and alleviate the complications associated with PAOD, enhancing patient outcomes and quality of life. [ 68 ] [ 69 ] [ 51 ] The use of DESs in peripheral arterial interventions has shown encouraging results in terms of primary patency (PP) and target lesion revascularization (TLR) compared with bare-metal stents (BMSs). [ 70 ] [ 71 ] [ 52 ] [ 53 ]
Different types of DESs are available on the market, each with different concentrations of drugs and showing varying efficacy. [ 52 ] [ 53 ] Among the different DESs, sirolimus -eluting stents and everolimus -eluting stents were found to be more effective than paclitaxel -eluting stents. [ 52 ] [ 53 ]
PCI and stent placement are considered when someone shows signs of reduced blood flow in the arteries that supply the heart or when tests, such as different types of coronary artery imaging, show a blockage in those arteries. [ 72 ] [ 73 ]
Symptoms can include:
In a medical setting, it's not very useful for doctors to rely solely on what people say about where their pain comes from or how it feels, because the way people describe chest pain caused by reduced blood flow to the heart can vary greatly and may not match what is typically taught in medical education or described in books and articles. [ 75 ] [ 76 ]
DES is not recommended in some cases as it may do more harm than good. DES is not suitable:
Bleeding disorders make DES unsuitable because of the need for anticoagulation drugs (blood thinners) during the procedure and in post-stenting aftercare. Other factors that could rule out the use of stents include a history of in-stent blockage, bleeding problems, complex or unsuitable coronary anatomy, or a short life expectancy due to other serious medical conditions. [ 80 ]
Stent placement risks include bleeding, allergic reactions to the contrast agents used to visualize the coronary arteries, and myocardial infarction. With percutaneous coronary intervention (PCI), the requirement for emergency coronary artery bypass graft (CABG) surgery has decreased as better practices have been introduced. [ 81 ] In some situations, coronary stenting is permitted in hospitals without cardiac surgery facilities, [ 82 ] but such permission remains controversial because of the rare but unpredictable risk of coronary artery perforation. [ 83 ]
A complication of coronary stenting is stent thrombosis (blood clots). This occurs when a new clot forms within the stent and occludes blood flow, causing a heart attack. [ 84 ] [ 85 ] [ 86 ]
DES were designed to specifically combat issues of restenosis that occurred with older bare-metal stents (BMS). [ 70 ] [ 87 ] Though less frequent with drug-eluting stents, restenosis can still occur. [ 88 ]
Since the advent of DES technology, the incidence of ISR has significantly decreased. [ 89 ] [ 90 ]
DES have been shown to be superior to BMS in reducing short-term complications of stenting in saphenous vein grafts. [ 91 ] However, the use of DESs in bypass grafts was not their originally intended use nor within the scope of originally regulatory approval ( US FDA , European Medicines Agency , etc.). The practice of using a medical device or drug in a way not specified in the original or current approved labeling is often referred to as " off-label " use. [ 92 ]
In regions were cardiac stenting has become commonplace, think tanks and advocacy groups express concern about the overzealous use of stents, [ 93 ] because patients who received stents for unapproved reasons [ 94 ] [ 95 ] often have worse outcomes compared to patients who received stents for approved uses. [ 96 ] [ 97 ] [ 98 ]
People who receive a coronary stent have different needs depending on their medical condition. Some patients are actually having a heart attack and need immediate life-saving emergency care. Other patients are at high risk of having a heart attack in the very near future. For people from each of these groups, PCI procedures may vary slightly, with particular modifications as to how they are sedated, pain management, and broader intensive care issues such as breathing support. [ 99 ]
Many people who are not in critical care situations are usually fully awake during the PCI procedure and DES placement, but they receive local anesthetic at the site of catheter entry, to ensure there is no pain. Different sedation and pain management practices are used by different medical institutions and practitioners, but patient comfort is always a primary consideration. [ 100 ]
The catheter/stent system is inserted into the body by piercing a peripheral artery (an artery in the arm or leg) and moved through the arterial system to deliver the DES into the blocked coronary artery. The stent is then expanded to widen (open) blocked or narrowed coronary arteries (narrowed by plaque buildup), caused by a condition called atherosclerosis. Peripheral arterial access is usually through the femoral (upper leg) or the radial artery (arm/wrist) and less often done through the brachial or ulnar artery (wrist/arm). [ 101 ] [ 102 ] In the past, controlling bleeding at the point of arterial access after the procedure was a problem. Modern arterial pressure bands and arterial closure systems now exist, which have helped control bleeding after the procedure, but it is still a concern. [ 103 ] [ 104 ] [ 105 ]
Modern catheter/stent systems are integrated medical devices, made of a guidewire, catheter, balloon, and stent. The stent tube mesh is initially collapsed onto the balloon of the device, and it is small enough to be passed through relatively narrow peripheral arteries. When in position, the balloon is inflated by introducing physiological saline, and this pushes the overlaying stent firmly into the diseased artery wall, inflation time and pressure are recorded during this placement procedure. After placement, the balloon is deflated, and the device is removed from the body, leaving the expanded stent in place and opening up the artery. [ 67 ] [ 106 ]
The interventional cardiologist decides how to treat the blockage in the best way during the PCI/DES placement, based on real-time data. The cardiologist uses imaging data provided by both intravascular ultrasound (IVUS), and fluoroscopic imaging (combined with a radiopaque dye). During the procedure, the information obtained from these two sources enables the cardiologist to track the path of the catheter-DES device as it moves through the arterial blood vessels. This information also helps determine both the location and characteristics of any plaque causing narrowing in the arteries. Data from these two techniques is used to correctly position the stent and to obtain detailed information relating to the coronary arterial anatomy. Given that this anatomy varies greatly among individuals, having this information becomes a prerequisite for effective treatment. The obtained data is recorded on video and may be used in cases when further treatment is needed. [ 107 ] [ 108 ] [ 109 ]
For many people the stenting procedure does not require staying in the hospital for any extended time period, most people leave the hospital the same day. Much of the time immediately after the stenting is spent in a recovery area to make sure the access site is not bleeding and to ensure vital signs are stable. [ 110 ]
In most hospital settings, the interventional cardiologist who performed the procedure will speak directly with the patient/family and give them information about how things went, and follow-up instructions. The nursing staff will keep an eye on the person's condition and use tools like ECG to monitor their heart. To prevent a blood clot from forming in the stent, medications are given right after the procedure. One common medication is plavix , which is a potent blood thinner that comes as a pill. Other medicines that thin the blood are also used, and it's typical to combine aspirin with plavix . [ 111 ] For people who have had a heart attack, the length of hospitalization is dependent on the degree of heart muscle damage caused by the event. [ 112 ]
A catheter with DES is a medical device, so people who receive it are given a medical device card. This card has information on the implanted DES and a medical device serial number. This information is important for future medical procedures, because it helps the doctors to know what type of device is in the person's body. Some arterial closure systems, which are devices that help to seal the access site after the procedure, are also medical devices and have their own informational cards. [ 113 ]
The access site is the place where the catheter enters the artery in the arm or leg. There is usually soreness and bruising at this site. This bruising and soreness usually get better after a week or so. People are advised to rest for a week or two and not to lift heavy things. This is mainly to make sure the access site heals well. It is normal to have follow-up appointments with a cardiologist or a primary care provider/general practitioner within a week or two of the procedure. [ 114 ] [ 115 ]
People who get a coronary stent usually have more check-ups every three to six months for the first year, but this can vary. They usually do not need to have another coronary angiography , which is a test that uses a special dye and X-rays to see the arteries of the heart. If the doctors suspect that the heart disease is getting worse, they can prescribe a stress test, which is a test that measures how the heart works during physical activity. People who have symptoms or show signs of reduced blood flow to the heart in a stress test may need to have a diagnostic cardiac re-catheterization. [ 116 ]
After PCI-stenting procedures, physical examinations are important. People who have a high risk of complications or more complex coronary problems may need to have angiography. This may be the case even if the results of non-invasive stress tests, which are tests that measure how the heart works during physical activity, appear normal. [ 117 ]
Cardiac rehabilitation activities depend on many factors, but mainly on how much the heart muscle was damaged before the PCI/DES procedure. Many people who have this procedure have not had a heart attack, and their hearts may be fine. Others may have had a heart attack and their hearts may have trouble pumping oxygen-rich blood to the body. Rehabilitation activities are tailored to each person's needs. [ 118 ]
DES are an improvement over older BMS devices as they reduce the chances of in-stent blockages. This reduces the incidence of serious post-stenting events such as, angina occurrence or recurrence, heart attacks, and death. They also reduce the likelihood of requiring another PCI procedure to open a blockage caused by the actual stent. [ 70 ]
The major benefit of drug-eluting stents (DES) when compared to bare-metal stents (BMS) is the prevention of in-stent restenosis (ISR). [ 70 ] Restenosis is a gradual re-narrowing of the stented segment that occurs most commonly between 3–12 months after stent placement. [ 119 ] High rates of restenosis associated with BMS prompted the development of DES, which resulted in a reduction of ISR incidence to around 5-10%. [ 120 ] Continued development of newer generation DES have resulted in the near-elimination of BMS from clinical practice. [ 121 ]
A key benefit of DES usage compared to BMS is a lower incidence of repeat revascularization procedures (re-stenting, invasive bypass surgeries etc.). Revascularization procedures are treatments that restore blood flow to parts of the heart that are not getting enough blood, a problem called ischemia. This can happen because of plaque buildup in the arteries of the heart, which can narrow or block them. [ 122 ] Rates of repeat revascularizations and stent thrombosis (blood clots) are significantly lower in those who received DES compared to BMS. [ 120 ]
Newer generations of DES devices have substantially improved safety outcomes, specifically regarding stent thrombosis, recurrent myocardial infarctions , and death. [ 122 ]
There are a number of very detailed medical device design considerations for DES products, these considerations are included in submissions for approval to regulatory authorities such as the US FDA: [ 18 ]
The drug choice is a critical design element and determining its true effectiveness in inhibiting neointimal growth due to the proliferation of smooth muscle cells that would cause restenosis can be a design challenge. Much of the neointimal hyperplasia seems to be caused by inflammation. [ 123 ]
Vascular stents are classified by the US as class III medical devices, [ 124 ] meaning that they pose the highest risk to patients and are subject to both general and premarket approval , which requires clinical trials and scientific evidence of safety and effectiveness, as well as rigorous mechanical testing. [ 125 ] During the mechanical testing process, universal testing machines induce bending, stretching, twisting, and putting pressure on vascular stents from various angles. [ 124 ]
The specific properties of each type of stent and its intended use depend on the results of testing, and vice versa: different types of stents may need different or additional tests based on where they will be placed in the body and what they will be used for. Some of these additional tests might include checking how well the stent can withstand being crushed or bent out of shape, its resistance to getting kinks in it, whether it resists corrosion or damage over time, as well as making sure any coatings on the device remain intact. [ 124 ]
Pharmacological therapy for coronary artery disease may be indicated instead of or in addition to invasive treatment. For those requiring percutaneous coronary intervention or surgery, medical therapy should be viewed as complementary to revascularization procedures, rather than an opposing strategy. Coronary artery bypass graft (CABG) surgery is an alternative to percutaneous coronary intervention (PCI) with drug-eluting stents (DES) for patients with ischemic left ventricular systolic dysfunction (LVSD). CABG is associated with lower risks of all-cause mortality, repeat revascularization, and myocardial infarction compared to PCI. [ 126 ]
The first procedure to treat blocked coronary arteries was coronary artery bypass graft surgery (CABG), wherein a section of vein or artery from elsewhere in the body is used to bypass the diseased segment of the coronary artery. In 1977, Andreas Grüntzig introduced percutaneous transluminal coronary angioplasty (PTCA), also called balloon angioplasty, in which a catheter was introduced through a peripheral artery and a balloon expanded to dilate the narrowed segment of the artery. [ 127 ]
As equipment and techniques improved, the use of PTCA rapidly increased, and by the mid-1980s, PTCA and CABG were being performed at equivalent rates. [ 128 ] Balloon angioplasty was generally effective and safe, but restenosis was frequent, occurring in about 30–40% of cases, usually within the first year after dilation. In about 3% of balloon angioplasty cases, failure of the dilation and acute or threatened closure of the coronary artery (often because of dissection) prompted emergency CABGs. [ 128 ]
Charles Theodore Dotter and Melvin Judkins had proposed using prosthetic devices inside arteries in the leg to maintain blood flow after dilation as early as 1964. [ 129 ] In 1986, Puel and Sigwart implanted the first coronary stent in a human patient. [ 130 ] Several trials in the 1990s showed the superiority of stent placement over balloon angioplasty. Restenosis was reduced because the stent acted as a scaffold to hold open the dilated segment of the artery. Acute closure of the coronary artery (and the requirement for emergency CABG) was reduced, because the stent repaired dissections of the arterial wall. By 1999, stents were used in 84% of percutaneous coronary interventions (i.e., those done via a catheter, and not by open-chest surgery). [ 130 ]
Early difficulties with coronary stents included a risk of early thrombosis (clotting) resulting in occlusion of the stent. [ 128 ] Coating stainless steel stents with other substances such as platinum or gold did not eliminate this problem. [ 130 ] High-pressure balloon expansion of the stent to ensure its full apposition to the arterial wall, combined with drug therapy using aspirin and another inhibitor of platelet aggregation (usually ticlopidine or clopidogrel) nearly eliminated this risk of early stent thrombosis. [ 128 ] [ 130 ]
Though it occurred less frequently than with balloon angioplasty or other techniques, stents nonetheless remained vulnerable to restenosis, caused almost exclusively by neointimal tissue growth (tissue formation in the inner 'tube' structure of the artery). To address this issue, developers of drug-eluting stents used the devices themselves as a tool for delivering medication directly to the arterial wall. While initial efforts were unsuccessful, the release (elution) of drugs with certain specific physicochemical properties from the stent was shown in 2001 to achieve high concentrations of the drug locally, directly at the target lesion, with minimal systemic side effects. [ 131 ] As currently used in clinical practice, "drug-eluting" stents refers to metal stents that elute a drug designed to limit the growth of neointimal scar tissue, thus reducing the likelihood of stent restenosis . [ 132 ]
The first type of DES to be approved by the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) were sirolimus-eluting stents (SES), which release a natural product called sirolimus , [ 133 ] an immunosuppressant drug. [ 134 ] SES were shown to reduce the need for repeat procedures and improve the outcomes of patients with coronary artery disease. [ 135 ] [ 136 ] [ 137 ] The sirolimus-eluting Cypher stent received CE mark approval in Europe in 2002, and then underwent a larger trial to demonstrate its safety and effectiveness for the US market. [ 138 ] [ 139 ] [ 140 ] The trial, published in 2003, enrolled 1058 patients with more complex lesions and confirmed the superiority of SES over bare metal stents in terms of angiographic and clinical outcomes. [ 141 ] [ 142 ] [ 143 ] [ 144 ] Based on these results, the Cypher stent received FDA approval and was released in the US in 2003. [ 130 ] The FDA approval process for DES involves submitting an investigational device exemption (IDE) application to conduct clinical trials under 21 CFR Part 812, and then a premarket approval (PMA) application to obtain marketing authorization under 21 CFR Part 8144. The FDA assigns the primary review responsibility to the Center for Devices and Radiological Health (CDRH), but also consults with the Center for Drug Evaluation and Research (CDER) for the drug component of the combination product.
The second type of DES to be approved by the EMA and the FDA were paclitaxel-eluting stents (PES), which release another natural product called paclitaxel . PES also reduced the need for repeat procedures and improved the outcomes of patients with different types of lesions and risk factors. The paclitaxel-eluting Taxus stent received FDA approval and was launched in the US in 2004, [ 145 ] after a series of trials that compared it with a bare metal stent in various settings. The trials showed a significant reduction in target lesion revascularization and major adverse cardiac events with the Taxus stent at 9 and 12 months. Both SES and PES use natural products as the active agents to prevent the recurrence of blockages in the arteries. [ 146 ] These DES have changed the practice of interventional cardiology and have become the preferred treatment for many patients with coronary artery disease. [ 146 ] [ 147 ] [ 148 ]
The initial rapid acceptance of DES led to their peak usage in 2005, accounting for 90% of all stent implantations, but concerns about late stent thrombosis led to a decrease in DES usage in late 2006. Subsequent studies reassured the medical community about their safety, showing that while DES may have a slightly higher risk for very late stent thrombosis, they significantly reduce target vessel revascularization without increasing the incidence of death or myocardial infarction; these reassurances led to a resurgence in DES utilization, although it did not reach the peak usage rates seen in early 2006. [ 149 ] [ 150 ]
The concept of using absorbable (also called biodegradable, bioabsorbable or bioresorbable) [ 151 ] materials in stents was first reported in 1878 by Huse who used magnesium wires as ligatures to halt the bleeding in vessels of three patients. Despite extensive search, the full name of this pioneer in the field remains elusive. [ 151 ] [ 152 ] In 20th century, a resorbable stent tested in humans was developed by the Igaki Medical Planning Company in Japan and was constructed from poly-L-lactic acid (a form of polylactic acid ); they published their initial results in 2000. [ 153 ] The German company Biotronik developed a magnesium absorbable (bioresorbable) stent and published clinical results in 2007. [ 153 ]
The first company to bring a bioresorbable stent to market was Abbott Vascular which received European marketing approval in September 2012; the second was Elixir which received its CE mark in May 2013. [ 154 ] [ 155 ] [ 156 ]
Despite the initial promise, the first-generation bioresorbable stents, such as the Absorb bioresorbable stent by Abbott, faced significant challenges in their performance. In comparison to current-generation drug-eluting stents, numerous trials revealed that these first-generation bioresorbsble stents exhibited poor outcomes. Specifically, they showed high rates of stent thrombosis (cases where an implanted coronary stent caused a thrombotic occlusion), target-lesion myocardial infarction (heart attack occurring at the site of the treated lesion), and target vessel revascularization (the need for further procedures to restore blood flow in the treated artery). In 2017, Abbott pulled its bioabsorbable stent, Absorb, from the European market after negative press regarding the device. [ 157 ] Boston Scientific also announced termination of its Renuvia bioresorbable coronary stent program as studies showed higher risk of serious adverse events. [ 158 ]
Currently, fully bioresorbable stents do not play a significant role in coronary interventions. [ 159 ] [ 160 ] [ 161 ] While various manufacturers are proposing new stents and continuing their development, [ 162 ] it remains uncertain whether they will have a substantial impact, unless there will be more data from their clinical trials. As of now, these stents are not widely utilized in practice. [ 163 ] [ 164 ] [ 159 ]
Due to challenges in developing resorbable stents, many manufacturers have focused efforts on targeting or reducing drug release through bioabsorbable-polymer coatings. Boston Scientific's Synergy bioabsorbable polymer stent has been shown potential to reduce the length of dual antiplatelet therapy post-implantation. [ 165 ] MicroPort's Firehawk target eluting stent has been shown to be non-inferior to traditional drug-eluting stents while using one-third of the amount of equivalent drug. [ 166 ]
As for the materials used to make a DES, the first DES products available for treating patients were stainless steel alloys composed of iron, nickel, and chromium and were based on existing bare metal stents. [ 123 ] These stents were hard to visualize with medical imaging, posed a risk of causing allergic responses, and were difficult to deliver. Subsequent new alloys were used, namely cobalt-chrome and platinum chrome, with improved performance. Bioresorbable stents have been developed in which the stent itself dissolves over time. [ 58 ] Materials explored for use include magnesium , polylactic acid , polycarbonate polymers, and salicylic acid polymers. [ 153 ] Resorbable stents have held the promise of providing an acute treatment that would eventually allow the vessel to function normally, without leaving a permanent device behind. [ 167 ]
For the coating of DES, one to three or more layers of polymer can be used: a base layer for adhesion, a main layer that holds and elutes (releases) the drug into the arterial wall by contact transfer, and sometimes a top coat to slow down the release of the drug and extend its effect. The first few drug-eluting stents to be licensed used durable coatings. The first generation of coatings appears to have caused immunological reactions at times, and some possibly led to thrombosis. This has driven experimentation and the development of new coating approaches. [ 154 ]
A research direction for a DES is to improve the material from which a device is made. The first-generation DES were made of stainless steel, while contemporary DES mainly consist of different kinds of alloys such as cobalt chromium and platinum chromium. In the current generation DES, thinner struts are employed than in the first-generation DES with preserved radial strength and radio-opacity. The lower strut thickness is believed to be associated with better stent-related outcomes including target lesion revascularization, myocardial infarction, and stent thrombosis. [ 168 ]
Another area of research for DES focuses on polymers. The current generation DES includes both durable polymer-coated stents and biodegradable polymer-coated stents. It has been reported that the presence of a durable polymer in the body over a long period can lead to chronic inflammation and neoatherosclerosis. To address this potential limitation, researchers have developed biodegradable polymer DES as an alternative solution. [ 168 ] [ 169 ] [ 170 ]
Scientists are also studying different drugs that could be used in DES to prevent restenosis. These drugs, which have immunosuppressive [ 134 ] and anti-cancer properties, aim to inhibit the growth of smooth muscle cells. Additionally, there is a specific type of stent that features an extra layer of anti-CD4 antibodies on its struts. This additional layer is positioned on top of the polymer coating and aims to capture circulating endothelial progenitor cells. The goal behind this design is to promote improved healing of the blood vessel lining, known as the endothelium . [ 168 ] [ 61 ]
A potential research focus for DES is the application of a polymer-free DES in clinical practice: moving away from polymer-based DES and instead using either a polymer-free DES or a drug-coated coronary stent. In the case of the polymer-free DES, it utilizes an abluminal coating of probucol to control the release of sirolimus. On the other hand, the drug-coated coronary stent has a micro-structured abluminal surface that allows for direct application of an anti-restenotic drug. [ 168 ] [ 61 ]
As of 2023 [update] there are over 20 different types of drug-eluting stents available, with differences in features and characteristics. [ 171 ]
The economic evaluation of DES has been a topic of extensive research. [ 172 ] In 2007, the overall incremental cost-effectiveness ratio in Europe was €98,827 per quality-adjusted life-years gained. Avoiding one revascularization with DES would cost €4,794, when revascularization with BMS costs €3,2606. [ 173 ]
There were controversies related to the use of DES. In 2012, a meta-analysis of clinical trial data [ 174 ] showed no benefit of the use of DES for people with stable coronary artery compared to treatment with drugs, yet, The New York Times interviewed David Brown, an author of the analysis, who said that more than half of patients with stable coronary artery disease were implanted with stents without even trying drug treatment and that he believed this happened because hospitals and doctors wanted to make more money. [ 175 ]
The interview sparked a debate among cardiologists, researchers, and patients about the appropriateness and effectiveness of DES for stable coronary artery disease: some agreed with the study's findings and questioned the overuse of stents, [ 176 ] [ 177 ] [ 178 ] while others criticized the study's methods and limitations and defended the benefits of stents, arguing that the interviewee's statement was "outrageous and defamatory" and that he was "insulting the integrity of the entire profession. [ 179 ] [ 180 ] [ 181 ]
In 2013 the Times of India reported that DES were widely overused and that Indian distributors used profits from high markups on DES to bribe doctors to use them. [ 182 ] [ 183 ]
In 2014 an investigation by the Maharashtra Food and Drug Administration found that high markups and bribery related to DES was still widespread. [ 184 ]
There have been several patent disputes related to drug-eluting stents. In one of them, Boston Scientific Corporation (BSC) has been found guilty of infringing upon a patent awarded to the University of Texas at Arlington in 2003 and licensed to TissueGen. [ 185 ] [ 186 ] [ 187 ] This patent involves technology developed by TissueGen founder Kevin Nelson, during his time as a faculty member at the university. The technology is designed to deliver drugs through an extruded fiber within an implanted vascular stent. As a result, BSC has been ordered to pay $42 million in lost royalties to both TissueGen and the university [ 185 ] [ 186 ]
Drug-eluting stents have been associated with legal and ethical controversies, and there have been related class action lawsuits. In 2014, the former owners of St. Joseph Medical Center in Maryland settled a class action lawsuit for $37 million with hundreds of patients who received unnecessary DES implantation. The lawsuit alleged that Dr. Mark Midei, a cardiologist at the center, falsified the degree of coronary artery stenosis to justify the use of DES, exposing the patients to increased risks of thrombosis, bleeding, and infection. Another DES manufacturer, Cordis Corporation, a subsidiary of Johnson & Johnson, was involved in lawsuits from people who suffered adverse events from the Cypher Stent, a stainless-steel DES coated with sirolimus, [ 188 ] [ 189 ] an immunosuppressant drug. [ 134 ] The Cypher Stent was approved by the FDA in 2003, but soon after, the FDA issued a Safety Warning following 290 reports of subacute thrombosis and at least 60 deaths related to the device. [ 188 ] [ 189 ]
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Drug-induced amnesia is amnesia caused by drugs. Amnesia may be therapeutic for medical treatment or for medical procedures, or it may be a side-effect of a drug, such as alcohol , or certain medications for psychiatric disorders, such as benzodiazepines . [ 1 ] It is seen also with slow acting parenteral general anaesthetics. [ citation needed ]
Amnesia is desirable during surgery, so general anaesthesia procedures are designed to induce it for the duration of the operation. Sedatives such as benzodiazepines, which are commonly used for anxiety disorders, can reduce the encoding of new memories, particularly in high doses (for example, prior to surgery in order for a person not to recall the surgery). [ 2 ] Amnestic drugs can be used to induce a coma for a child breathing using mechanical ventilation, or to help reduce intracranial pressure after head trauma . [ 3 ] [ failed verification ]
Researchers are currently experimenting with drugs which induce amnesia in order to improve understanding of human memory, and develop better drugs to treat psychiatric disorders and memory-related disorders. People with Alzheimer's disease and other forms of dementia are likely to benefit. By understanding the ways in which amnesia-inducing drugs interact with the brain, researchers hope to better understand the ways in which neurotransmitters aid in the formation of memory. By stimulating rather than depressing these neurotransmitters, memory may improve. [ 1 ]
Holmes et al. (2010) [ 4 ] commented that the media misrepresented two recent studies as research on "erasing" traumatic memories, but showed the fear response associated with stressful memory could be greatly reduced whilst the factual memory of the trauma remained intact. Similarly, Brunet et al. (2008) found that the people with chronic posttraumatic stress disorder who were treated with propranolol for a single day had a reduced response to existing trauma while retaining memory of the trauma. [ 5 ] In the process of remembering, the memory needs to be restored in the brain. By introducing an amnesia-inducing drug during this process, the memory can be disrupted. While the memory remains intact, the emotional reaction is damped, making the memory less overwhelming. Researchers believe this drug will help patients with post-traumatic stress disorder be able to better process the trauma without reliving the trauma emotionally. [ citation needed ] This has raised legal and ethical concerns should drugs be found to have altered the memory of traumatic events that occur in victims of crimes (e.g. murder attempt), and whether it is therapeutically desirable to do so. [ 4 ] [ 6 ]
Amnesia can result from a side-effect of prescription or non-prescription drugs. Both substance use and alcohol can cause both long-term and short-term memory loss, resulting in blackouts .
The most commonly used group of prescription drugs which can produce amnesia are benzodiazepines, especially if combined with alcohol, however, in limited quantities, triazolam (Halcion) is not associated with amnesia or memory impairment. [ 7 ]
Nepenthe , literally named anti-sorrow, is a substance mentioned in the Odyssey given to Helen of Troy , said to originate from Egypt . Consumption causes sorrowful memories to be forgotten. [ 12 ] [ 13 ]
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Drug-related gingival hyperplasia is a cutaneous condition characterized by enlargement of the gums noted during the first year of drug treatment . [ 1 ] Although the mechanism of drug related gingival hyperplasia is not well understood, some risk factors for the condition include the duration of drug use and poor oral hygiene . [ 2 ] In most cases, alternative drugs are given, in order to avoid this side effect . [ 3 ]
This dentistry article is a stub . You can help Wikipedia by expanding it .
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Drug addiction recovery groups are voluntary associations of people who share a common desire to overcome their drug addiction . Different groups use different methods, ranging from completely secular to explicitly spiritual. Some programs may advocate a reduction in the use of drugs rather than outright abstention. One survey of members found active involvement in any addiction recovery group correlates with higher chances of maintaining sobriety. [ citation needed ] Although there is not a difference in whether group or individual therapy is better for the patient, studies show that any therapy increases positive outcomes for patients with substance use disorders. [ 1 ] The survey [ which? ] found group participation increased when the individual members' beliefs matched those of their primary support group (many addicts are members of multiple addiction recovery groups). [ 2 ] Analysis of the survey results found a significant positive correlation between the religiosity of members and their participation in twelve-step programs (these programs describe themselves as spiritual rather than religious ) and to a lesser level in non-religious SMART Recovery groups, the correlation factor being three times smaller for SMART Recovery than for twelve-step addiction recovery groups. [ citation needed ] Religiosity was inversely related to participation in Secular Organizations for Sobriety . [ 2 ]
A survey [ medical citation needed ] of a cross-sectional sample of clinicians working in outpatient facilities (selected from the SAMHSA On-line Treatment Facility Locator) found that clinicians referring clients to only twelve-step groups were more likely than those referring their clients to twelve-step groups and "twelve-step alternatives" to believe less strongly in the effectiveness of cognitive behavioral and psychodynamic -oriented therapy, and were likely to be unfamiliar with twelve-step alternatives. A logistic regression of clinicians' knowledge and awareness of cognitive behavioral therapy effectiveness and preference for the twelve-step model was correlated with referring exclusively to twelve-step groups. [ 3 ]
Twelve-step programs are mutual aid organizations for the purpose of recovery from substance addictions , behavioral addictions , and compulsions . Developed in the 1930s by alcoholics, the first twelve-step program, Alcoholics Anonymous (AA), aided its membership to overcome alcoholism . [ 4 ] Since that time, dozens of other organizations have been derived from AA's approach to address problems as varied as drug addiction , compulsive gambling , sex and overeating . All twelve-step programs utilize a version of AA's suggested twelve steps first published in the 1939 book Alcoholics Anonymous: The Story of How More Than One Hundred Men Have Recovered from Alcoholism . [ 5 ]
As summarized by the American Psychological Association (APA), the process involves the following: [ 4 ]
Participants attend meetings and are able to make new connections with other members who are striving towards a similar goal. If a person is unable to attend a meeting face-to-face, many of the groups have meetings by phone or online as another option. Each group has its own textbook, workbooks or both, which provide information about their program of recovery and suggestions on how to "work the steps". Often, free literature is available for anyone who asks for it at a meeting. This provides potential new members or family members with relevant information about both the addiction and that specific group's version of the twelve-step process of recovery. New members are invited to work with another member who has already been through the twelve-steps at least once. That person serves as a guide to the new member, answers questions and provides feedback as the new member goes through the steps. These groups are spiritually based and encourage a belief in a power greater than the members. Most do not have one specific conception of what that means and allow the member to decide what spirituality means to them as it applies to their recovery. The groups emphasize living on a spiritual yet not necessarily religious basis. Groups typically advocate for complete abstinence, usually from all drugs including alcohol . This is because of the perceived potential for cross-addiction, the idea that there is a tendency to trade one addiction for another. Despite the idea of cross-addiction being accepted as real in many addiction recovery groups, there is said to be little empirical evidence to support the idea and recent research suggests that the opposite is more likely to be true.
The following is a list of twelve-step drug addiction recovery groups. Twelve-step programs for problems other than drug addiction also exist.
These groups do not follow the twelve-step recovery method, although their members may also attend twelve-step meetings. It is common for individuals to try many different meetings and groups while in recovery. What works for one may not work for another, so trying different types of meetings can be helpful to someone seeking recovery from drugs and alcohol.
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Dry needling , also known as trigger point dry needling and intramuscular stimulation , [ 1 ] [ 2 ] is a treatment technique used by various healthcare practitioners, including physical therapists , physicians , and chiropractors , among others. [ 3 ] Acupuncturists usually maintain that dry needling is adapted from acupuncture , but others consider dry needling as a variation of trigger point injections. [ 2 ] It involves the use of either solid filiform needles [ 4 ] or hollow-core hypodermic needles for therapy of muscle pain, including pain related to myofascial pain syndrome . Dry needling is mainly used to treat myofascial trigger points, but it is also used to target connective tissue, neural ailments, and muscular ailments. The American Physical Therapy Association defines dry needling as a technique used to treat dysfunction of skeletal muscle and connective tissue, minimize pain, and improve or regulate structural or functional damage. [ 4 ]
There is conflicting evidence regarding the effectiveness of dry needling. Some results suggest that it is an effective treatment for certain kinds of muscle pain, while other studies have shown no benefit compared to a placebo ; however, not enough high-quality, long-term, and large-scale studies have been done on the technique to draw clear conclusions about its efficacy. [ 5 ] [ 6 ] [ 7 ] Currently, dry needling is being practiced in the United States, Canada, Europe, Australia, and other parts of the world. [ 1 ]
The origin of the term dry needling is attributed to Janet G. Travell . In her 1983 book, Myofascial Pain and Dysfunction: Trigger Point Manual , Travell uses the term dry needling to differentiate between two hypodermic needle techniques when performing trigger point therapy. However, Travell did not elaborate on the details of the dry needling techniques; the current techniques were based on traditional and Western medical acupuncture. [ 1 ]
Travell described two techniques: the injection of a local anesthetic and the mechanical use of a hypodermic needle without injecting a solution. [ 8 ] Travell preferred a, 1.5-in hypodermic needle for trigger point therapy and used this needle for both injection therapy and dry needling. Travell never used an acupuncture needle. Travell had access to acupuncture needles but reasoned that they were far too thin for trigger point therapy. She preferred hypodermic needles because of their strength and tactile feedback: "A 22- gauge , 3.8-cm (1.5-in) needle is usually suitable for most superficial muscles. In hyperalgesic patients, a 25-gauge, 3.8-cm (1.5-in) needle may cause less discomfort, but will not provide the clear feeling of the structures being penetrated by the needle and is more likely to be deflected by the dense contraction knots that are the target... A 27-gauge needle, 3.8-cm (1.5-in) needle is even more flexible; the tip is more likely to be deflected by the contraction knots and it provides less tactile feedback for precision injection". [ 8 ]
The solid filiform needle used in dry needling is regulated by the FDA as a Class II medical device described in the code titled "Sec. 880.5580 Acupuncture needle is a device intended to pierce the skin in the practice of acupuncture". [ 9 ] Per the Food and Drug Act of 1906 and the subsequent amendments to said act, the FDA definition applies to how the needles can be marketed and does not mean that acupuncture is the only medical procedure where these needles can be used. [ 10 ] [ 11 ] [ 12 ] [ 13 ] [ 14 ] Dry needling using such a needle contrasts with the use of a hollow hypodermic needle to inject substances such as saline solution , botox or corticosteroids to the same point.
The founder of Integrative Systemic Dry Needling (ISDN), Yun-Tao Ma, has spearheaded the "dry needling" movement in the United States. Ma states, "Although ISDN originated in traditional Chinese methods, it has developed from the ancient empirical approach to become modern medical art rooted in evidence-based thinking and practice." [ 15 ] Ma also states that, "Dry needling technique is a modern Western medical modality that is not related to traditional Chinese acupuncture in any way. Dry needling has its own theoretical concepts, terminology, needling technique, and clinical application." [ 16 ]
The American Academy of Orthopedic Manual Physical Therapists states:
Dry needling is a neurophysiological evidence-based treatment technique that requires effective manual assessment of the neuromuscular system. Physical therapists are well trained to utilize dry needling with manual physical therapy interventions. Research supports that dry needling improves pain control, reduces muscle tension, normalizes biochemical and electrical dysfunction of motor end plates, and facilitates an accelerated return to active rehabilitation.
Dry needling for the treatment of myofascial (muscular) trigger points is based on theories similar, but not exclusive, to traditional acupuncture; both acupuncture and dry needling target the trigger points, which are a direct and palpable source of patient pain. [ 1 ] A high degree of correspondence is reported between myofascial trigger point dry needling and western medical acupuncture.
Unlike traditional Chinese acupuncture, which is based on concepts like Qi (energy flow) and meridians, Western medical acupuncture does not adhere to these traditional principles. Instead, it focuses on evidence-based medicine and is typically practiced by healthcare professionals trained in conventional Western medicine. The primary goals are pain relief, inflammation reduction, and promoting healing by stimulating nerves, muscles, and connective tissue.
Acupuncture and dry needling are similar in the underlying phenomenon and neural processes between trigger and acupuncture points. There is a high degree of correspondence between published locations of trigger points and classical acupuncture points for the relief of pain. [ 17 ] Dry needling, and its treatment techniques and desired effects, would be most directly comparable to the use of 'a-shi' points in acupuncture. [ 18 ] However, dry needling theory only begins to describe the complex sensation referral patterns that have been documented as "channels" or "meridians" in Chinese Medicine. What further distinguishes dry needling from traditional acupuncture is that it does not use the full range of traditional theories of Chinese Medicine, which is used to treat not only pain, but also other non-musculoskeletal issues that often cause pain. The distinction between trigger points and acupuncture points for the relief of pain is blurred.
The technique for dry needling depends on which tissue is being targeted and the overall objective of the treatment. For example, one of the most common treatment objectives for dry needling, myofascial trigger points (TrPs), differs physiologically from treatments for scar tissue, connective tissue problems, and other medical issues. [ 4 ]
In the treatment of trigger points for persons with myofascial pain syndrome , dry needling is an invasive procedure in which a filiform needle is inserted into the skin and muscle directly at a myofascial trigger point. A myofascial trigger point consists of multiple, hyperirritable contraction knots related to the production and maintenance of the pain cycle; essentially, myofascial trigger points will generate much local pain upon stimulation or irritation. [ 4 ] Deep dry needling for treating trigger points was first introduced by the Czechian neurologist Karel Lewit in 1979. [ 19 ] Lewit had noticed that the success of injections into trigger points in relieving pain was apparently unconnected to the analgesic used. [ 6 ]
Dry needling can be divided into categories in terms of depth of penetration: deep and superficial dry needling. [ 4 ] Deep dry needling will inactivate myofascial trigger points by provoking a local twitch response (LTR), which is an involuntary spinal cord reflex in which the muscle fibers in the taut band of muscle contract. The LTR indicates the proper placement of the needle in a trigger point. Dry needling that elicits LTRs improves treatment outcomes, [ 7 ] and may work by activating endogenous opioids . [ 5 ] The activation of the endogenous opioids is for an analgesic effect using the gate control theory of pain. [ 8 ] In addition, deep dry may also decrease pain, increase range of motion, and minimize myofascial trigger point irritability. [ 4 ] In regards to the factor of pain reduction, relief occurs at four central levels: local pain, spinal pain through nerves, brain stem pain, and higher brain center pain.
The relief of myofascial trigger points has been more highly researched than the relief of connective tissues, muscle fascia, muscle tension, and scar tissue; however, the American Physical Therapy Association claims that there potentially may be some benefits of dry needling on these ailments according to some available evidence. [ 4 ] The APTA also disclaims that dry needling should not be used as a standalone procedure, but should be used in conjunction with other treatment methods, including manual soft tissue mobilization, neuromuscular re-education, functional retraining, and therapeutic exercises. [ 4 ] Once the needle is inserted, one can manually or electrically stimulate the filiform needle depending for the desired effect of treatment.
There is currently no standardized form of dry needling. There is a general scarcity of extensive research in the field. Many studies published about dry needling are not randomized, contain small sample sizes, and have high dropout rates. A review recommended the usage of dry needling, compared to sham or placebo, for decreasing pain immediately after treatment and at 4 weeks in patients with upper quarter myofascial pain syndrome. However, the authors caution that "the limited number of studies performed to date, combined with methodological flaws in many of the studies, prompts caution in interpreting the results of the meta-analysis performed". [ 17 ] Similarly, a second review of dry needling found insufficient high-quality evidence for the use of direct dry needling for short and long-term pain and disability reduction in patients with musculoskeletal pain syndromes. The same review reported that robust evidence validating the clinical diagnostic criteria for trigger point identification or diagnosis is lacking and that high-quality studies demonstrate that manual examination for the identification and localization of a trigger point is neither valid nor reliable between examiners. [ 18 ]
Three more recent reviews reached similar conclusions: little evidence supporting the use of trigger point dry needling to treat upper shoulder pain and dysfunction, [ 5 ] evidence not robust enough to draw a clear conclusion about safety and efficacy, [ 6 ] and that dry needling for the treatment of myofascial pain syndrome in the lower back appeared to be a useful addition to standard therapies, but stated clear recommendations could not be made because the published studies were small and of low quality. [ 7 ] However, a retrospective analysis of 2,910 dry needling interventions as reported by Mabry, et al. identified no reported safety events when dry needling was performed by physical therapists. [ 20 ]
Dry needling is considered invasive. Invasive treatments are associated with infections and cutaneous infections , which can be avoided, however, by using good aseptic (sterile) technique. [ 10 ] Nonetheless, the procedure is increasing in popularity despite the unanswered questions regarding its overall effectiveness and safety. Mild adverse events following dry needling are commonly bleeding, bruising, and pain. Severe adverse effects include pneumothorax , injury to the central nervous system and spine, and blood-borne infection transmission. [ 15 ] The American Medical Association made a press release in 2016 that said physical therapists and other non-physicians practicing dry needling should – at a minimum – have standards that are similar to the ones for training, certification, and continuing education that exist for acupuncture. AMA board member Russell W. H. Kridel, MD: "Lax regulation and nonexistent standards surround this invasive practice. For patients' safety, practitioners should meet standards required for licensed acupuncturists and physicians." [ 21 ]
Additional adverse effects of dry needling include cardiac tamponade and hematoma . During a recent study, a self-reported survey of almost 230,000 people, 8.6% (19726 patients) reported experiencing at least one adverse effect. 2.2% (4,963 patients) reported an adverse effect that required further treatment. However, since this study was based on the patient's self-reporting rather than actual incidence, the collective findings cited above are probably lower than the actual incidence. [ 22 ] Because dry needling sometimes involves blood and other bodily fluids, there are sometimes risk of transmission of multiple forms of hepatitis as well as HIV . [ 23 ]
The debated distinction between dry needling and acupuncture has become a controversy because it relates to an issue of scope of practice of various professions. Acupuncturists claim that dry needling is a form of acupuncture that does not fall in the scope of physical therapists, chiropractors, or the majority of other healthcare professionals; whereas those healthcare professionals claim dry needling is not acupuncture, but rather a procedure that is rooted in biomedical modern sciences. [ 1 ] Becoming a certified acupuncturist requires hundreds of hours spent in educational programs, national-level exams, and good professional standing. On the other hand, to be certified in dry needling requires continued education or a certification program that is not yet regulated with strict standards; in addition, there is a general lack of policymakers, evaluation systems, or healthcare standards governing the technique of dry needling. [ 1 ]
Many physical therapists and chiropractors have asserted that they are not practicing acupuncture when dry needling; [ 24 ] however, much of dry needling research has been done concerning acupuncture. [ 10 ] They assert that much of the basic physiological and biomechanical knowledge that dry needling utilizes is taught as part of their core physical therapy and chiropractic education and that the specific dry needling skills are supplemental to that knowledge and not exclusive to acupuncture. Many acupuncturists have argued that dry needling appears to be an acupuncture technique requiring minimal training that has been re-branded under a new name (dry needling). Whether dry needling is considered to be acupuncture depends on the definition of acupuncture, and it is argued that trigger points do not correspond to acupuncture points or meridians. [ 25 ] They correspond by definition to the ad hoc category of 'a-shi' acupoints. [ 26 ] It is important to note that this category of points is not necessarily distinct from other formal categories of acupoints. In 1983, Janet Travell described trigger point locations as 92% in correspondence with known acupuncture points. In 2006, a journal article concluded that the two point systems are in over 90% agreement. [ 27 ] In 2009, Dorsher and Fleckenstein conclude that the strong (up to 91%) consistency of the distributions of trigger point regions' referred pain patterns to acupuncture meridians provides evidence that trigger points most likely represent the same physiological phenomenon as acupuncture points in the treatment of pain disorders. [ 28 ]
A comparison of Western trigger points to traditional acupuncture points corroborates the 92% correspondence. [ 29 ] In 2011, The Council of Colleges of Acupuncture and Oriental Medicine published a position paper describing dry needling as an acupuncture technique. [ 30 ]
According to a qualitative review, dry needling combined with acupuncture was more effective in alleviating pain and achieved a higher response rate than dry needling alone. However, there is no clear research on whether dry needling is a better treatment choice over laser, physical therapy, or other combined treatments. [ 31 ]
The North Carolina Acupuncture Licensing Board has published a position statement asserting that dry needling is acupuncture and thus is covered by the North Carolina Acupuncture Licensing law, and is not within the present scope of practice of Physical Therapists. [ 32 ] The Attorney General was asked for an opinion by the North Carolina Acupuncture Licensing Board which he gave in 2011: "In our opinion, the Board of Physical Therapy Examiners may determine that dry needling is within the scope of practice of physical therapy if it conducts rulemaking under the Administrative Procedure Act and adopts rules that relate dry needling to the statutory definition of practice of physical therapy." However, the North Carolina Rules Review Committee of the legislative branch found that the North Carolina Physical Therapy Board had no statutory authority for the proposed rule. The Physical Therapy board subsequently decided that they had the right to declare dry needling within scope anyway "The Board believes physical therapists can continue to perform dry needling so long as they possess the requisite education and training required by N.C.G.S. § 90–270.24(4), but there are no regulations to set the specific requirements for engaging in dry needling." [ citation needed ]
In January 2014, the Oregon Court of Appeals ruled that the Oregon Board of Chiropractic Examiners did not have the statutory authority to include dry needling in the scope of practice for chiropractors in that state. The ruling did not address whether chiropractors have the medical expertise to use dry needling or whether the training they were given was adequate. [ 33 ] Pending further discussion of training requirements, the Oregon Physical Therapist Licensing Board has advised all Oregon physical therapists against practicing dry needling. They have not changed their ruling that dry needling is within the scope of practice for Oregon Physical Therapists. [ 34 ]
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Dual consciousness (also known as dual mind or divided consciousness ) is a hypothesis in neuroscience . It is proposed that it is possible that a person may develop two separate conscious entities within their one brain after undergoing a corpus callosotomy . The idea first began circulating in the neuroscience community after some split-brain patients exhibited alien hand syndrome (AHS), which led some scientists to believe that there must be two separate consciousnesses within the brain's left and right hemispheres in competition with one another once the corpus callosum is severed. [ 1 ]
The idea of dual consciousness has caused controversy in the neuroscience community. No conclusive evidence of the proposed phenomenon has been discovered.
During the first half of the 20th century, some neurosurgeons concluded that the best option of treating severe epilepsy was by severing the patient's corpus callosum. The corpus callosum is the primary communication mechanism between the brain's two cerebral hemispheres. For example, communication across the corpus callosum allows information from both the left and right visual fields to be interpreted by the brain in a way that makes sense to comprehend the person's actual experience (e.g., visual inputs from both eyes are interpreted by the brain to make sense of the experience that you are looking at a computer that is directly in front of you). The procedure of surgically removing the corpus callosum is called a corpus callosotomy . Patients who have undergone a corpus callosotomy are colloquially referred to as " split-brain patients". This is because their brain's left and right hemispheres are no longer connected by the corpus callosum. [ citation needed ]
Split-brain patients have been subjects for numerous psychological experiments that sought to discover what occurs in the brain after the primary interhemispheric pathways have been disrupted. Notable researchers in the field include Roger Sperry , one of the first to publish ideas involving a dual consciousness; and his famous graduate student, Michael Gazzaniga . Their results found a pattern among patients: severing the entire corpus callosum stops the interhemispheric transfer of perceptual, sensory, motor, and other forms of information. For most cases, corpus callosotomies did not in any way affect patients' real-world functioning; however, those psychology experiments have demonstrated some differences between split-brain patients and other subjects. [ citation needed ]
The first successful corpus callosotomies on humans were performed in the 1930s. [ 2 ] The purpose of the procedure was to alleviate the effects of epilepsy when other forms of treatment (medications) had failed to stop the violent convulsions associated with the disorder. [ 3 ] Epileptic seizures occur because of abnormal electrical discharges that spread across areas of the brain. [ 4 ] William Van Wagenen proposed the idea of severing the corpus callosum to eliminate transcortical electrical signals across the brain's hemispheres. [ 5 ] If this could be achieved, then the seizures should be reduced or even eliminated. [ citation needed ]
The general procedure of a corpus callosotomy is as follows. The patient is put under anesthesia. Once the patient is in deep sleep, a craniotomy is performed. This procedure removes a section of the skull, leaving the brain exposed and accessible to the surgeon. The dura mater is pulled back so the deeper areas of the brain, including the corpus callosum, can be seen. Specialized instruments are placed into the brain that allows safe severing of the corpus. Initially, a partial callosotomy is performed, which only severs the front two-thirds of the callosum. [ 6 ] Though the corpus callosum loses a majority of its functioning during a partial callosotomy, it does not completely lose its capabilities; because the back section of the callosum is preserved, visual information is still sent across both hemispheres. If the operation does not succeed in reducing the seizures, a complete callosotomy is needed to reduce the severity of the seizures. [ citation needed ]
A similar type of procedure, known as a commissurotomy , involves severing a number of interhemispheric tracts (such as the anterior commissure , the hippocampal commissure and the massa intermedia of the thalamus ) in addition to the corpus callosum. [ 7 ]
After surgery, the split-brain patients are often given extensive neuropsychological assessments. One finding among split-brain patients is that many of them feel normal after the surgery and do not feel that their brains are "split". [ 8 ] The corpus callosotomy and commissurotomy have been successful in reducing, and in some cases, eliminating epileptic seizures. This aligns with Van Wagenen's theory. [ citation needed ]
Alien hand syndrome , sometimes used synonymously with anarchic hand [ 9 ] is a neurological disorder in which the afflicted person's hand appears to act on its own. Alien hand syndrome has been documented in some split-brain patients.
The first instance of alien hand syndrome was reported in 1908 by Kurt Goldstein . [ 10 ] This incident occurred to a woman in her 50s whose left hand grabbed her throat without her making the effort to do so. She was able to remove her hand, but it took a great deal of effort to do so. Upon her death, an autopsy was performed which concluded that the event may have been caused by several strokes in her right hemisphere and corpus callosum. In the 1940s, reports surfaced of patients who had undergone corpus callosotomies that were experiencing uncontrollable hand movements following surgery. In these instances, the actions of one’s left hand conflicted with the actions of one’s right hand. The initial diagnosis for these experiences was "diagnostic dyspraxia".
There are three main types of alien hand syndrome. [ 11 ] The first is the frontal variant, which is characterized by the nondominant hand grabbing items and manipulating objects. The second is the callosal variant, which is the most common and is characterized by the uncontrollable and conflicting movement of a right-handed patient’s left hand. Callosal alien hand syndrome often occurs alongside other symptoms of callosal damage such as alexia , the diminished or absent ability to comprehend written language, and visual anomia, the inability to name objects seen in the right vision field. [ 12 ] The third type is the posterior variant, which is characterized by the affected hand rising in the air and making non-purposeful movements. [ 13 ]
The classic sign of alien hand syndrome is that the affected person cannot control one of their hands. For example, if a split-brain patient with alien hand syndrome is asked to pick up a glass with their right hand, as the right hand moves over to the glass, the left hand will interfere with the action, thwarting the right hand's task. The interference from the left hand is completely out of the control of the patient and is not being done "on purpose". Affected patients at times cannot control the movements of their hands. Another example included patients unbuttoning a shirt with one hand, and the other hand simultaneously re-buttoning the shirt (although some reported feeling normal after their surgery). [ 14 ] [ 15 ] Switching one's attention from one task to another can also lessen the amount of control that they can allocate to their affected hand. [ 11 ]
When scientists first started observing the alien hand syndrome in split-brain patients, they began to question the nature of consciousness and began to theorize that perhaps when the corpus callosum is cut, consciousness is also split into two separate entities. This development added to the general appeal of split-brain research. [ citation needed ]
In 1978, Michael Gazzaniga and Joseph DeLoux [ 16 ] [ 17 ] discovered a unique phenomenon among split-brain patients who were asked to perform a simultaneous concept task. The patient was shown two pictures: of a house in the winter time and of a chicken's claw. The pictures were positioned so they would exclusively be seen in only one visual field of the brain: the winter house was positioned so it would only be seen in the patient's left visual field (LVF), which corresponds to the brain's right hemisphere, and the chicken's claw was placed so it would only be seen in the patient's right visual field (RVF), which corresponds to the brain's left hemisphere.
A series of pictures was placed in front of the patients. Gazzaniga and LeDoux then asked the patient to choose a picture with his right hand and a picture with his left hand. The paradigm was set up so the choices would be obvious for the patients. A snow shovel is used for shoveling the snowy driveway of the winter house and a chicken's head correlates to the chicken's claw. The other pictures do not in any way correlate with the two original pictures. In the study, a patient chose the snow shovel with his left hand (corresponding to his brain's right hemisphere) and his right hand chose the chicken's head (corresponding to the brain's left hemisphere). When the patient was asked why he had chosen the pictures he had chosen, the answer he gave was "The chicken claw goes with the chicken head, and you need a snow shovel to clean out the chicken shed."
Both the winter house and the shovel were being projected to the patient from his LVF, so his right hemisphere received and processed the information; this input is completely independent from what is going on in the RVF, which involves the chicken's claw and head (the information being processed in the left hemisphere). The human brain's left hemisphere is primarily responsible for interpreting the meaning of the sensory input it receives from both fields; however, the patient's left hemisphere had no knowledge of the winter house. Because of this, the left hemisphere had to invent a logical reason for why the shovel was chosen. Since the only objects it had to work with are the chicken's claw and head, the left hemisphere interprets the meaning of choosing the shovel as "it is an object necessary to help the chicken, which lives in a shed, therefore, the shovel is used to clean the chicken’s shed". Gazzaniga famously coined the term left-brain interpreter [ 18 ] to explain this phenomenon.
The Gazzaniga–LeDoux studies were based on previous studies done by Sperry and Gazzaniga. [ 19 ] Sperry's experiment included a subject being seated at a table, with a shield blocking the visions from the subject's hands, including the objects on the table and the examiner seated across. The shield was also used as a viewing screen. On the shield, the examiner can select to present the visual material to both hemispheres or to selective hemispheres by means of having the viewing screen. The patient is briefly exposed to the stimuli on the viewing screen. The stimuli shown to the left eye goes to the right hemisphere, and the visual material shown to the right eye will be projected to the left hemisphere. During the experiment, when the stimulus was shown to the left side of the screen, the patient indicated he did not see anything. Patients have shown the inability to describe in writing or in speech the stimuli that was shown briefly to the left side. The speaking hemisphere, which in most people is the left hemisphere, would not have awareness of stimulus being shown to the right hemisphere (left visual field), except the left hand was able to point to the correct object. Based on his observations and data, Sperry concluded each hemisphere possessed its own consciousness. [ citation needed ]
Antti Revonsuo explained a procedure that was similar in nature to the Sperry–Gazzaniga design. Split-brain patients were shown a picture with two objects: a flower and a rabbit. The flower is exclusively shown in the right visual field, which is interpreted by the left hemisphere; and the rabbit is exclusively shown in the left visual field, which is interpreted by the right hemisphere. The left brain sees the flower while the right brain is simultaneously viewing the rabbit. When the patients were asked what they saw, they said they only saw the flower and did not see the rabbit. The flower is in the right visual field and the left hemisphere can only see the flower. The left hemisphere dominates the interpretation of the stimulus and since it cannot see the rabbit (only being represented in the right hemisphere), patients do not believe they saw a rabbit. They can, however, still point to the rabbit with their left hand. Revonsuo stated that it seemed that one consciousness saw the flower and another consciousness saw the rabbit independently from one another. [ 15 ]
Rhawn Joseph observed two patients who had both undergone a complete corpus callosotomy. Joseph observed that the right hemisphere of one of the patients is able to gather, comprehend, and express information. The right hemisphere was able to direct activity to the patient's left arm and leg. The execution of the left arm and leg's action as was inhibited by the left hemisphere. Joseph found that the patient's left leg would attempt to move forward as if to walk straight but the right leg would either refuse to move or begin to walk in the opposite direction. After observing the struggles of the execution of activities involving the left and right arms and legs, Joseph was led to believe that the two hemispheres each possessed their own consciousness. [ 20 ]
Joseph also noted that the patient had other specific instances of conflict between the right and left hemispheres including, the left hand (right hemisphere) carrying out actions contrary to the left hemisphere's motives, such as the left hand turning off the television immediately after the right hand turned it on. Joseph found that the patient's left leg would only allow the patient to return home when the patient was going for a walk and would reject continuing to go for that walk.
In the laboratory, a patient was given two different fabrics: a wire screen in his left hand and a piece of sandpaper in his right hand. The patient received two different fabrics out of his view so that neither eye nor hemisphere visually saw what his hands were given. When the patient was indicating what fabric was in the left hand, he was able to correctly indicate and point with the left hand to the wire screen after it had been set on a table. As he pointed with his left hand, however, the right hand tried to stop the left hand and make the left hand point to the fabric that the right hand was holding. The left hand continued to point at the correct fabric, even though the right hand tried to forcefully move the left hand. During the struggle, the patient also verbalized feelings of animosity by saying, "That’s wrong!" and "I hate this hand." Joseph concluded that the left hemisphere did not understand at all why the left hand (right hemisphere) would point to a different material. [ 20 ]
The most powerful arguments against the dual consciousness theory are:
Gonzalo Munevar has proposed an alternative explanation to demonstrate that these strange behaviors are spawned from areas in the brain and not by a dual consciousness. [ 1 ] Two cortical areas in particular, the supplementary motor area (SMA) and the premotor cortex (PMC), are crucial in the planning of executing motor tasks to external stimuli presented in the person's perceptual field. [ 22 ] For example, a person may pick up a glass of water with their right hand and put it up to their lips for a drink. The person may have picked up the glass with their right hand, but well before this action takes place, the PMC and SMA consider a variety of different possibilities of how this action could be performed. They could have picked it up with their left hand, their mouth, or their foot. They could have done it quickly or slowly. Many possibilities are entertained, but few are actually executed. These actions are sent from the PMC to the Motor Cortex for execution. The rest are inhibited by the SMA and are not performed. [ 23 ]
The processes of the SMA and PMC are done unconsciously. The SMA and PMC consider the many alternative actions many milliseconds before the chosen action takes place. [ 23 ] The person is never consciously aware of these alternative possibilities the brain has considered before they pick it up with the right hand; they just do it. The action of picking up the glass with the right hand is also performed unconsciously. It may be preferable to use their right hand because they are right-handed , and doing so is therefore more comfortable; alternatively, the glass may be placed to their right, and the possibility that expends the least amount of energy is using the right hand to pick it up.
Another important fact about the PMC is that its activation is bilateral. When it is activated, it is activated in both hemispheres of the brain. Gazzaniga observed and wrote about this phenomenon. [ 23 ] When the corpus callosum is severed, many interhemispheric interactions are disrupted. Many areas of the brain become compromised, including the SMA. If the SMA has trouble regulating and inhibiting the actions of the PMC, it is possible that conflicting sets of actions may be sent to the MC and performed (accounting for both hands reaching for the glass, even if only one hand is intended to grab it). It would make the appearance that there is a dual consciousness competing for dominance over the other for control of the brain, but it is not the case.
The disappearance of alien hand syndrome in some split-brain patients is not evidence of one consciousness "defeating" the other and taking complete control of the brain. [ 23 ] It is likely that the plasticity of the brain may be the cause for alleviating the disorder. Eventually the split patient's brain may find adaptive routes to compensate for the lost interhemispheric communication, such as alternative pathways involving subcortical structures that perform subcortical interhemispheric inhibition to regain a sense of normalcy between the two hemispheres.
Michael Gazzaniga, while working on the model of dual consciousness, came to the conclusion that simple dual consciousness (i.e. right-brain/left-brain model of the mind) is an oversimplification, and the brain is organized into hundreds or even thousands of modular-processing systems. [ 24 ] [ 25 ]
The theory of a division of consciousness was touched upon by Carl Jung in 1935 when he stated, "The so-called unity of consciousness is an illusion ... we like to think that we are one but we are not." [ 26 ]
Similar models which hypothesize that mind is formed from many smaller agents (i.e. the brain is made up of a constellation of independent or semi-independent agents) were also described by:
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In the mental health field, a dual relationship is a situation where multiple roles exist between a therapist , or other mental health practitioner, and a client. [ 1 ] Dual relationships are also referred to as multiple relationships , and these two terms are used interchangeably in the research literature. [ 1 ] [ 2 ] The American Psychological Association (APA) Ethical Principles of Psychologists and Code of Conduct (also referred to as the APA ethics code [ 3 ] ) is a resource that outlines ethical standards and principles to which practitioners are expected to adhere. Standard 3.05 of the APA ethics code outlines the definition of multiple relationships. Dual or multiple relationships occur when:
In addition, the standard provides a description of when to avoid multiple relationships (e.g., when the relationship causes harm to the client or impairs the psychologist's competence) and when these relationships are not considered unethical (e.g., when the relationship does not exploit the client or impair competence). [ 4 ] [ 5 ] [ 6 ]
Several "helping" fields which are not strictly psychological in nature, but which still involve a therapeutic counseling environment, also have stringent policies involving dual relationships and the avoidance of such relationships. For example, the National Association of Social Workers [NASW], which regulates 132,000 social workers across the world, names multiple types of dual relationships. [ 7 ] This includes sexual, financial, personal or religious relationships which could become exploitative due to the differences in power between the worker and the client. Social workers are advised by the NASW to communicate with their clients when such a relationship arises or could arise, and are advised to take steps to avoid dual relationships wherever possible. The NASW recognizes, however, that dual relationships can be unavoidable in some types of communities, such as in rural communities or military installations.
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Dubai School of Dental Medicine (DCDM), founded in 2013, is a dental medical college located in Dubai , United Arab Emirates . The dental college is accredited by the Ministry of Higher Education, [ 1 ] offering both undergraduate and post-graduate programs. [ 2 ]
The college is a newly established home-grown dental institution launched to support the United Arab Emirates (UAE) community with dental care services and education. [ 3 ] [ 4 ]
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Ductal papilloma is a group of rare and benign papillary salivary gland tumors arising from the duct system: [ 1 ] [ 2 ]
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Ductopenia refers to a reduction in the number of ducts in an organ , in particular the absence of bile ducts of the expected size in the portal tract of the liver. [ 1 ] It is the histological hallmark of vanishing bile duct syndrome (typically <0.5 bile ducts per portal triad ). The most common cause of ductopenia is primary biliary cholangitis .
Other causes of ductopenia include failing liver transplant , Hodgkin's lymphoma , graft-versus-host disease (GVHD), sarcoid, cytomegalovirus infection, HIV , and medication toxicity , such as phenothiazines .
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The Duke Activity Status Index ( DASI ) is an assessment tool used to evaluate the functional capacity of patients with cardiovascular disease (CVD), such as coronary artery disease , myocardial infarction , and heart failure . [ 1 ]
In clinical practice , DASI can be used to assess the effects of medical treatments and cardiac rehabilitation as well. [ 2 ] Positive responses are summed up to get a total score, which ranges from 0 to 58.2. Higher scores would indicate a higher functional capacity. [ citation needed ]
The instrument is copyrighted by one of its authors, Mark Hlatky. [ 3 ] [ 4 ]
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Duke E. Cameron is an American cardiac surgeon . Formerly Chief of Cardiac Surgery at Johns Hopkins University School of Medicine; the James T. Dresher Sr. Professor of Surgery; Director of Pediatric Cardiac Surgery; and Director of The Dana and Albert "Cubby" Broccoli Center for Aortic Diseases , at the Johns Hopkins Hospital , he returned to Hopkins in 2023. His clinical interests include:
He is the editor, along with Stephen C. Yang, of Current Therapy in Thoracic and Cardiovascular Surgery.
In January 2008, Cameron reported a very large surgical series, the 30-year history of surgical treatment in 372 cases of Marfan syndrome at Johns Hopkins Hospital.
He graduated from Harvard College and Yale School of Medicine . [ 1 ]
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Duke Treadmill Score is a tool for predicting the risk of ischemia or infarction in the heart muscle . [ 1 ] The score is a function of data from an exercise test : [ citation needed ] [ 1 ]
Angina index is zero if no pain occurs during the exercise, one if the pain is limited to the exercise period but the patient can continue the exercise ( typical angina ), and two if a pain is a reason to stop the exercise test. [ 2 ] [ 3 ]
Duke treadmill scores typically range from –25 (highest risk) to +15 (lowest risk). One-year mortality and five-year survival rates respectively for the results of the Duke treadmill score have been reported as follows: [ 4 ] [ 5 ] [ 6 ]
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Duodenal-Jejunal Bypass Liner , or Gastric Bypass Stent , [ 1 ] Common brand names include EndoBarrier , is an implantable medical device in the form of a thin flexible 60 cm-long tube that creates a physical barrier between ingested food and the duodenum / proximal jejunum . The duodenal-jejunal bypass liner prevents the interaction of food with enzymes and hormones in the proximal intestine to treat type 2 diabetes and obesity . The duodenal-jejunal bypass liner is delivered endoscopically and has been tested on the morbidly obese (those with a body mass index [BMI] greater than 40) as well as obese patients with a BMI less than 40, particularly those with difficult-to-manage type 2 diabetes. Despite a handful of serious adverse events such as gastrointestinal bleeding, abdominal pain, and device migration — all resolved with device removal — initial clinical trials have produced promising results in the treatment's ability to improve weight loss and glucose homeostasis outcomes. [ 2 ] [ 3 ]
The device is connected at one end to the beginning of the duodenum (first portion of the small intestine from the stomach) and at the other the mid-jejunum (the secondary stage of the small intestine). A nitinol anchor secures the bag at the duodenum, ensuring the liner doesn't migrate and that the chyme (the semifluid mass of partially digested food that exits the stomach) completely enters into the liner. This prevents the partially digested food from entering the first and initial part of the secondary stage of the small intestine, mimicking the effects of the biliopancreatic portion of Roux en-Y gastric bypass (RYGB) surgery. This reduces the amount of calories absorbed and causes bile and pancreatic fluids to be redistributed later in the mid-jejunum for reduced breakdown and absorption of the chyme. [ 2 ] [ 3 ] [ 4 ]
Initial clinical research by Rubino et al. in 2006 produced two hypotheses for why duodenal-jejunal bypass is effective in improving glucose homeostasis. Their "hindgut hypothesis" claims that by expediting the delivery of chyme to the distal intestine , the secretion of the gut hormone GLP-1 and glucose-dependent insulin is more effectively promoted, improving glucose metabolism. The "foregut hypothesis," on the other hand, states that by bypassing the duodenum and proximal jejunum (the initial parts of the small intestine), the inhibiting hormone GIP is secreted less, resulting in improved glucose tolerance. [ 5 ] [ 6 ] As of 2015 [update] , those hypotheses continue to be tested, with Xiong et al. finding elements of both being involved. [ 7 ]
A specialized study of the product noted that the rate of adverse events could reach 84.4% of the 1,056 cases counted, with a moderate adverse event rate of 20.5% and a serious adverse event rate of 3.7%. [ 8 ]
Common adverse event, other than those related to surgery, were mainly implant rejections (e.g., abdominal pain, vomiting), gastrointestinal bleeding , anchor displacement, ulceration , and perforation , as well as liner-related adverse events (e.g., obstruction, ectopia) and inflammatory conditions such as pancreatitis , cholecystitis , and cholangitis .
Severe adverse events includes perforation of the esophagus , gastrointestinal hemorrhage , anchor tissue overgrowth, perforation of the duodenal bulb, hepatic abscess and acute pancreatitis, the majority (85%) of serious adverse events were directly or indirectly related to anchor.
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Politics
Economy
The Duplessis Orphans (French: les Orphelins de Duplessis ) were a population of Canadian children [ 1 ] wrongly certified as mentally ill by the provincial government of Quebec and confined to psychiatric institutions in the 1940s and 1950s. Many of these children were deliberately miscertified in order to acquire additional subsidies from the federal government. They are named for Maurice Duplessis , who served as Premier of Quebec for five non-consecutive terms between 1936 and 1959. The controversies associated with Duplessis, and particularly the corruption and abuse concerning the Duplessis orphans, have led to the popular historic conception of his term as Premier as La Grande Noirceur ("The Great Darkness") by its critics.
The Duplessis Orphans have accused both the government of Quebec and the Roman Catholic Church of wrongdoing. The Catholic Church has denied involvement in the scandal, and disputes the claims of those seeking financial compensation for harm done. [ 2 ]
It is believed to be the largest case of child abuse in Canadian history outside of the Canadian Indian residential school system . [ 3 ] [ 4 ]
During the 1940s and 1950s, limited social services were available to residents of Quebec . Before the Quiet Revolution of the 1960s, [ 5 ] most of the social services available were provided through the Roman Catholic Church . Among their charges were people considered to be socially vulnerable: those living in poverty, alcoholics or other individuals deemed unable to retain work, unwed mothers, and orphans . [ 6 ]
The Catholic Church urged [ 7 ] many mothers to admit children to orphanages despite not having been formally orphaned due to their "bastard" status (being born to unwed mothers ). Some of these orphanages were operated by Roman Catholic religious institutions, due to a lack of secular investment in social services; they encouraged unwed mothers to leave their children there, so that they might be raised in the Roman Catholic church. Maternity homes for unwed mothers, too, then prevalent, often encouraged the giving up of these "bastard" children. [ 8 ] [ 9 ]
The Loi sur les Asiles d'aliénés (Lunatic Asylum Act) of 1909 governed mental institution admissions until 1950. The law stated the mentally ill could be committed for three reasons: to care for them, to help them, or as a measure to maintain social order in public and private life. However, the act did not define what a disruption of social order was, leaving the decision to admit patients up to psychiatrists. [ 10 ]
The provincial government of Union Nationale Premier Maurice Duplessis received subsidies from the federal government for building hospitals, but received substantially fewer subsidies to support orphanages. Government contributions were only $1.25 a day for orphans, but $2.75 a day for psychiatric patients. This disparity in funding provided a strong financial incentive for reclassification. Under Duplessis, the provincial government was responsible for a significant number of healthy older children being deliberately classified as mentally ill [ 11 ] [ 12 ] [ 13 ] and sent to psychiatric hospitals, based on diagnoses made for fiscal reasons. [ 14 ] Duplessis also signed an order-in-council which changed the classification of orphanages into hospitals in order to provide them with federal subsidies. [ 15 ]
A commission in the early 1960s investigating mental institutions after Duplessis' death revealed one-third of the 22,000 patients classified as "mentally ill" were classified as such for the province's financial benefit, and not due to any real psychiatric deficit. [ 5 ] Following the publication of the Bédard report in 1962, the province ceased retaining the institutional notion of "asylum". When many of the orphans reached adulthood, in light of these institutional changes, they were permitted to leave the facilities. [ 10 ]
Years later, long after these institutions were closed, survivors of the asylums began to speak out about child abuse which they endured at the hands of some staff and medical personnel. [ 16 ] [ 17 ] Many who have spoken publicly about their experiences claim that they had been abused physically and sexually , and were subjected to lobotomies , electroshock and straitjackets . [ 14 ]
In a psychiatric study completed by one of the involved hospitals, middle-aged Duplessis Orphans reported more physical and mental impairments than the control group . In addition, the orphans were less likely to be married or to have a healthy social life. 80% reported they had suffered a traumatic experience between the ages of 7 and 18. Over 50% said they had undergone physical, mental, or sexual abuse. About 78% reported difficulty functioning socially or emotionally in their adult life. [ 18 ]
By the 1990s, about 3,000 survivors and a large group of supporters formed the Duplessis Orphans Committee, seeking damages from the Quebec provincial government. In March 1999, the provincial government made an offer of approximately CAD$ 15,000 as full compensation to each of the victims. The offer was rejected and the provincial government was harshly criticized, with Quebec's ombudsman at the time, Daniel Jacoby, saying that the government's handling of the affair trivialized the abuse alleged by the victims. [ 19 ] In 2001, the claimants received an increased offer from the provincial government for a flat payment of $10,000 per person, plus an additional $1,000 for each year of wrongful confinement to a mental institution. The offer amounted to approximately $25,000 per orphan, [ 20 ] but did not include any compensation for alleged victims of sexual or other abuse.
After the offer was accepted by representatives of the Duplessis Orphans Committee, the result was bitterly contested by other members upon learning that under the terms of the settlement , the committee's lawyer, president, and former public relations official would receive six- to seven-figure payments, in comparison with the paltry amount given to the actual victims. The committee subsequently voted to replace both the president and the public relations official. [ 21 ] Critics of the judgment pointed out that three of the bureaucrats running the government's compensation program were being paid over $1,000 per day for work, [ 22 ] whereas the orphans themselves received the same amount of money for an entire year of their confinement.
Seven religious communities were involved in operating some of the facilities: the Sisters of Providence , the Sisters of Mercy , the Grey Nuns of Montreal , the Sisters of Charity of Quebec, the Little Franciscans of Mary , the Brothers of Notre-Dame-de-la-Misericorde, and the Brothers of Charity . [ 5 ] When the settlement with the provincial government was reached, the orphans agreed to drop any further legal action against the Catholic Church. [ 14 ] This offended some survivors; in 2006, one of the Orphans, Martin Lécuyer, stated, "It's important for me, that the Church, the priests, that they recognize they were responsible for the sexual abuse, and the aggression. It's not for the government to set that peace... It's an insult, and it's the biggest proof that the government is an accomplice of the Church." [ 23 ] : 376
In 1999, researchers Léo-Paul Lauzon and Martin Poirier issued a report arguing that both the Quebec provincial government and the Catholic Church made substantial profits by falsely certifying thousands of Quebec orphans as mentally ill during Duplessis' premiership. The authors made a conservative estimate that religious groups received $70 million in subsidies (measured in 1999 dollars) by claiming the children as "mentally deficient", while the government saved $37 million simply by having one of its orphanages redesignated from an educational institution to a psychiatric hospital. A representative of a religious order involved with the orphanages accused the authors of making "false assertions". [ 24 ] In 2010, it was estimated that approximately 300–400 of the original Duplessis orphans were still alive. [ 25 ]
On March 4, 1999, after a criminal investigation where 240 Duplessis orphans alleged 321 criminal accusations against those in charge of the hospitals, former Quebec Premier Lucien Bouchard declared a public apology to the orphans, but "without blaming or imputing legal responsibility to anyone." [ 26 ]
In 2004, some Duplessis orphans asked the Quebec government to unearth an abandoned cemetery in the east end of Montreal , which they believed to have held the remains of orphans who may have been the subject of human experimentation . According to testimony by individuals who were at the Cité de St-Jean-de-Dieu insane asylum, the orphans in the asylum's care were routinely used as non-consensual experimental subjects, and many died as a consequence. The group wanted the government to exhume the bodies so that autopsies may be performed. [ 27 ] In November 2010, the Duplessis orphans made their case before the United Nations Human Rights Council . [ 28 ] In 2021, preliminary ground-penetrating radar analyses on grounds around former Canadian Indian residential schools allegedly indicated the presence of unmarked graves that could include the remains of Indigenous children that were also mainly administered by Christian churches. This has spurred further calls for the Quebec government and the Catholic Church to excavate former psychiatric hospital sites where the orphans were committed, with a class action lawsuit launched in 2018 denouncing the earlier settlement as "an insult" and not a "true apology" by the government and religious organizations. [ 26 ]
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Duroziez's disease is a congenital variant of mitral stenosis . It was described in 1877 by Paul Louis Duroziez . [ 1 ]
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The Dutch hypothesis provides one of several biologically plausible explanations for the pathogenesis of chronic obstructive pulmonary disease (COPD) , a progressive disease known to be aetiologically linked to environmental insults such as tobacco smoke . [ 1 ]
The Dutch hypothesis was originally proposed by Dick Orie and his team in 1961 at the University of Groningen . [ 2 ] [ 3 ] According to Orie, "Bronchitis and Asthma may be found in one patient at the same age but as a rule there is a fluent development from bronchitis in youth to a more asthmatic picture in adults, which in turn develops into bronchitis of elderly patients." [ 4 ] This supposition was later named the Dutch hypothesis by a colleague, Professor C. Fletcher. [ 2 ] Specifically, clinical characteristics such as allergy and bronchial hyperresponsiveness that are commonly observed in individuals afflicted with asthma were viewed as likely determinants of the life-threatening disease, COPD (in the Netherlands, the term chronic non-specific lung disease was adopted as an umbrella term for asthma and COPD). [ citation needed ]
More recent molecular biology research suggests that the pathogenesis of asthma and COPD may share overlapping pathways involving innate biological susceptibility, coupled with environmental factors which can trigger the different diseases. Genetic association studies that have uncovered the same polymorphisms in people with asthma and COPD provide support for the notion that the two conditions share some biological characteristics; implicated genes include ADAM33 , CCL5 and IL17F . [ 5 ]
Although clinically debated, [ 6 ] [ 7 ] the Dutch hypothesis remains one of four main plausible explanations which could help explain the complex pathogenesis of COPD, others being the protease -antiprotease hypothesis (involving alpha 1-antitrypsin overexpression and consequent alpha-1 proteinase deficiency), the British hypothesis (regarding a putative aetiological role of acute bronchial infections), and the autoimmunity hypothesis. [ 1 ]
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Duvelisib , sold under the brand name Copiktra , is a medication used to treat chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL), and follicular lymphoma after other treatments have failed. [ 5 ] It is taken by mouth. [ 5 ] It is a PI3 kinase inhibitor . [ 6 ]
Common side effects include diarrhea, low white blood cells , rash, feeling tired, fever, and muscle pains. [ 5 ] Other serious side effects include inflammation of the lungs and infections. [ 5 ] It is a dual inhibitor of PI3Kδ and PI3Kγ . [ 7 ]
Duvelisib is indicated to treat adults with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) who have received at least two prior therapies that did not work or stopped working. [ 1 ] [ 5 ] [ 6 ] CLL is a type of cancer that begins in the white blood cells, and SLL is a type of cancer that begins mostly in the lymph nodes. [ 6 ]
Duvelisib may cause infections, diarrhea, inflammation of the intestines and lungs, skin reactions, and high liver enzyme levels in the blood. [ 6 ]
Patients taking duvelisib may have a higher risk of death. [ 6 ]
Duvelisib is a Phosphoinositide 3-kinase inhibitor , specifically of the delta and gamma isoforms of PI3K. [ 8 ] This class of compounds works by preventing PI3K from playing its role in transducing signals from outside of cells into various intracellular pathways involved in cell cycle regulation, apoptosis, DNA repair, senescence, angiogenesis and cell metabolism, including the PI3K/AKT/mTOR pathway . [ 8 ]
Duvelisib, also known as IPI-145, was discovered by Intellikine, [ 9 ] a company founded in September 2007 based on biochemistry research from the lab of Kevan Shokat at the University of California San Francisco . [ 10 ]
In mid-June 2016, Infinity announced results of Phase II clinical trial of duvelisib. [ 8 ]
In November 2016, Infinity exclusively licensed the worldwide rights to duvelisib to Verastem Oncology for little money compared to earlier deals; the deal included no upfront payment, a $6 million milestone for success in a Phase 3 trial in chronic lymphocytic leukemia, a $22 million payment for an FDA approval, and royalties. [ 11 ]
Duvelisib received orphan drug designation in the United States for the treatment of peripheral T-cell lymphoma (PTCL) in 2019, [ 12 ] [ 13 ] the treatment of chronic lymphocytic leukemia and small lymphocytic lymphoma in 2013, [ 14 ] and the treatment of follicular lymphoma in 2013. [ 15 ]
In September 2020, duvelisib was sold by Verastem to Secura Bio, Inc. for $70 million and additional payments based on milestones and royalties. [ 16 ]
The US Food and Drug Administration (FDA) required the drug manufacturer, Secura Bio, to submit the final 5-year survival results from the clinical trial, called DUO trial, a phase III, randomized, open-label trial. [ 6 ] It was conducted in 319 participants with CLL or SLL who received a previous therapy that did not work or stopped working. [ 6 ] These final results showed a possible increased risk of death with duvelisib compared to the monoclonal antibody ofatumumab. [ 6 ] The rate of serious side effects, dose modifications, and deaths resulting from these side effects were also higher among participants who received duvelisib. [ 6 ] The serious side effects included infections, diarrhea, inflammation of the intestine and lungs, skin reactions, and elevated liver enzyme levels in the blood. [ 6 ] These safety findings were similar for other medicines in the same PI3 kinase inhibitor class. [ 6 ]
In April 2018, Verastem filed a New Drug Application (NDA) for duvelisib for the treatment of relapsed or refractory chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and accelerated approval for relapsed or refractory follicular lymphoma (FL). The FDA approved the application in September 2018. [ 17 ] [ 18 ] In April 2022, the FDA withdrew the approval of duvelisib for relapsed or refractory follicular lymphoma on request of its then owner, Secura Bio. [ 19 ]
Duvelisib is intended to be used in people who have received at least two prior systemic therapies, and carries a black box warning due to the risk of fatal/serious toxicities: infections, diarrhea or colitis, cutaneous reactions and pneumonitis. [ 20 ]
On 25 March 2021, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Copiktra, intended for the treatment of adults with relapsed or refractory chronic lymphocytic leukaemia (CLL) and refractory follicular lymphoma (FL). [ 21 ] The applicant for this medicinal product is Verastem Europe GmbH. [ 21 ] Duvelisib was approved for medical use in the European Union in May 2021. [ 3 ]
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In the military, dwell time is the amount of time that service members spend in their home station between deployments to war zones. It is used to calculate the deploy-to-dwell ratio. Dwell time is designed to allow service members a mental and physical break from combat and to give them time with their families. It is an important component of long term military readiness. [ 1 ]
From the early days of the Global War on Terrorism until 2011, dwell time for American service members was reduced to a maximum of 12 months for most service members, [ 2 ] increasing the deploy-to-dwell ratio to over 1:1 (15 months vs 12 months). "Dwell time at home stations became nothing more than getting ready for the next deployment." [ 3 ] In October, 2011, the United States Department of Defense extended dwell time for U.S. soldiers to 24 months for every year deployed to a war zone, [ 4 ] [ 5 ] decreasing the deploy-to-dwell ratio to 1:2.
A 2012 study of over 65,000 service members found that longer periods at home between deployments reduced the incidence of post traumatic stress disorder . [ 6 ] Another study found that longer dwell times were associated with a reduced risk of suicide. [ 7 ]
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Dynamic psychiatry is based on the study of emotional processes , their origins, and the mental mechanisms underlying them. It is in direct contrast with descriptive psychiatry , which is based on the study of observable symptoms and behavioral phenomena rather than underlying psychodynamic processes. Most modern psychiatrists believe that it is most helpful to combine the two approaches in a biopsychosocial model . [ 1 ]
Schopenhauer is an ancestor of modern dynamic psychiatry. [ 2 ] [ 3 ]
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Dyscopia consists of the Latin root copia , [ 1 ] which means abundance or plenty (see cornucopia ), and the Greek prefix dys- , which means "bad", "abnormal", "difficult" or "impaired". [ 2 ]
This word has assumed two meanings, both of which are essentially a play on words based on the phonic similarity of the words "copy" and "cope" with copia . [ 1 ]
In the field of neurology , dyscopia is used to describe a type of developmental coordination disorder related to dyslexia and dysgraphia (inability to read or write). Specifically, it is taken to mean difficulty with coping . Sometimes a similar word, " acopia ", is mistaken to mean the same, [ 3 ] although this is not a medical term and has no basis in Latin.
The term "dyscopia" has also made its way into general medical parlance as a tongue-in-cheek shorthand notation for patients who, after being examined and found to have no specific medical condition, are deemed to be not coping with certain aspects of their lives, and are presumed to be seeking treatment as a form of comfort from the medical profession . [ 4 ] More recently, and controversially, the term has been used in this context as a diagnosis for admission to hospital.
The words have also been used in medical notes as a cryptic indication that certain members of a seriously ill patient's family are not coping with the situation and should be afforded some extra consideration for their feelings when the case is being discussed.
In neurology, the word "dyscopia" is used to describe a condition which is common as one of the sequelae of cerebral commisurotomy , a neurosurgical procedure in which the left and right hemispheres of the brain are separated by severing the corpus callosum . This procedure has been shown to reduce the frequency and severity of seizures in extreme cases of epilepsy . [ 5 ]
An affected individual will exhibit difficulty with copying simple line drawings. This is often accompanied to lesser or greater degree by difficulty with writing and other fine motor skills. [ 6 ]
Terms such as "social admission", "atypical presentation", and even the derogatory terms " bed blocker " or "crumblie" [ 7 ] [ 8 ] have been used in medical notes synonymously with dyscopia or acopia as a reason for hospital admission.
The use of the term has become sufficiently commonplace in medical notes that a recent publication of a psychiatric dictionary even cites it as an actual diagnosis. [ 9 ]
Patients who are likely to be labelled with one of these terms are sometimes frail and elderly or people with long-term disabilities. Their failure to cope is often a result of inadequate social support coupled with a deterioration of functional capability which is not clearly linked to an obvious or specific medical or psychiatric pathology.
Sometimes, however, despite the fact that terms such as acopia and social admission can be considered tongue-in-cheek by those adhering to the strictest of medical and psychiatric terminology, they can frequently describe a range of "symptoms", such as extreme lability and emotionality when demands are not met and the unwillingness of a minority of patients that might be encountered in psychiatry, to function and make ends meet, despite the fact that such patients might be lucid and able-bodied.
A possible controversy associated with using dyscopia and acopia as diagnoses could arise when wrongfully applied to those who have genuine problems with mobility; genuine medical conditions may be overlooked. Investigation of symptoms is a legitimate reason for admission, and if medical staff are too swift to dismiss concerns by use of such informal labels, genuine symptoms may not be taken seriously and investigated. This may lead to treatable conditions being overlooked, and in turn, result in compromised quality of life and unnecessary suffering.
Dyscopia (and likewise acopia), in this context, is not generally used by the medical community for fear of insulting the patient and bringing the caregiver's professional standing into question. [ 7 ] [ 8 ]
Acopia has been adopted as the name of a company based in Crawley, UK, presumably referring the correct Latin root of the word copia meaning abundance.
The words also appear to be gaining traction in common usage as colloquialisms [ 10 ] meaning emotional lability over trivial events or circumstances. This may well assist in demystifying the term and discouraging its usage in medical circles.
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In medicine , both ancient and modern, a dyscrasia is any of various disorders. The word has ancient Greek roots meaning "bad mixture". [ 1 ] The concept of dyscrasia was developed by the Greek physician Galen (129–216 AD), who elaborated a model of health and disease as a structure of elements, qualities, humors, organs, and temperaments (based on earlier humorism ). Health was understood in this perspective to be a condition of harmony or balance among these basic components, called eucrasia . Disease was interpreted as the disproportion of bodily fluids or four humours : phlegm, blood, yellow bile, and black bile. The imbalance was called dyscrasia . In modern medicine, the term is still occasionally used in medical context for an unspecified disorder of the blood, such as a plasma cell dyscrasia .
To the Greeks, it meant an imbalance of the four humors : blood , black bile , yellow bile , and water ( phlegm ). These humors were believed to exist in the body, and any change in the balance among the four of them was the direct cause of all disease .
This is similar to the concepts of bodily humors in the Tibetan medical tradition and the Indian Ayurvedic system, which both relate health and disease to the equality (Skt. samatā ) or inequality (Skt. viṣamatā ) of the quantities of three (or four) bodily humors, generally translated as wind, bile, and phlegm (and blood).
The term is still occasionally used in medical contexts for an unspecified disorder of the blood. Specifically, it is defined in current medicine as a morbid general state resulting from the presence of abnormal material in the blood, usually applied to diseases affecting blood cells or platelets. Evidence of dyscrasia can be present with a WBC (white blood cell) count of over 1,000,000. [ 2 ]
" Plasma cell dyscrasia " is sometimes considered synonymous with paraproteinemia or monoclonal gammopathy . [ 3 ]
H2 receptor antagonists , such as famotidine and nizatidine , in use for treatment of peptic ulcers , are known for causing blood dyscrasia – leading to bone marrow failure in 1 out of 50,000 patients. [ citation needed ]
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Dysdiadochokinesia ( DDK ) is the medical term for an impaired ability to perform rapid, alternating movements (i.e., diadochokinesia ). Complete inability is called adiadochokinesia. The term is from Greek δυς dys "bad", διάδοχος diadochos "working in turn", κίνησις kinesis "movement". [ 2 ]
Abnormalities in diadochokinesia can be seen in the upper extremity, lower extremity and in speech. The deficits become visible in the rate of alternation, the completeness of the sequence, and in the variation in amplitude involving both motor coordination and sequencing. [ 3 ] [ 4 ] Average rate can be used as a measure of performance when testing for dysdiadochokinesia. [ 5 ]
Dysdiadochokinesia is demonstrated clinically by asking the patient to tap the palm of one hand with the fingers of the other, then rapidly turn over the fingers and tap the palm with the back of them, repeatedly. This movement is known as a pronation / supination test of the upper extremity. A simpler method using this same concept is to ask the patient to demonstrate the movement of trying a doorknob or screwing in a light bulb. When testing for this condition in legs, ask the patient to tap your hand as quickly as possible with the ball of each foot in turn. Movements tend to be slow or awkward. The feet normally perform less well than the hands. [ 6 ] When testing for dysdiadochokinesia with speech the patient is asked to repeat syllables such as /pə/, /tə/, and /kə/; variation, excess loudness, and irregular articular breakdown are signs of dysdiadochokinesia. [ 5 ]
Dysdiadochokinesia is a feature of cerebellar ataxia and may be the result of lesions to either the cerebellar hemispheres or the frontal lobe (of the cerebrum ), it can also be a combination of both. [ 3 ] It is thought to be caused by the inability to switch on and switch off antagonising muscle groups in a coordinated fashion due to hypotonia , secondary to the central lesion. [ 7 ]
Dysdiadochokinesia is also seen in Friedreich's ataxia and multiple sclerosis , as a cerebellar symptom (including ataxia, intention tremor and dysarthria ). It is also a feature of ataxic dysarthria. Dysdiadochokinesia often presents in motor speech disorders ( dysarthria ), therefore testing for dysdiadochokinesia can be used for a differential diagnosis. [ 5 ]
Dysdiadochokinesia has been linked to a mutation in SLC18A2 , which encodes vesicular monoamine transporter 2 (VMAT2). [ 8 ]
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Dysesthesia is an unpleasant, abnormal sense of touch. Its etymology comes from the Greek word "dys," meaning "bad," and "aesthesis," which means "sensation" (abnormal sensation). It often presents as pain [ 1 ] but may also present as an inappropriate, but not discomforting, sensation. It is caused by lesions of the nervous system , peripheral or central, and it involves sensations, whether spontaneous or evoked, such as burning, wetness, itching, electric shock, and pins and needles . [ 1 ] Dysesthesia can include sensations in any bodily tissue, including most often the mouth, scalp, skin, or legs. [ 1 ]
It is sometimes described as feeling like acid under the skin. Burning dysesthesia might accurately reflect an acidotic state in the synapses and perineural space. Some ion channels will open to a low pH , and the acid sensing ion channel has been shown to open at body temperature, in a model of nerve injury pain. Inappropriate, spontaneous firing in pain receptors has also been implicated as a cause of dysesthesia. [ citation needed ]
People with dysesthesia can become incapacitated with pain, despite no apparent damage to the skin or other tissue. [ citation needed ]
Dysesthesia can generally be described as a class of neurological disorders. It can be further classified depending on where it manifests in the body, and by the type of sensation that it provokes. [ citation needed ]
Cutaneous dysesthesia is characterized by discomfort or pain from touch to the skin by normal stimuli, including clothing. The unpleasantness can range from a mild tingling to blunt, incapacitating pain. [ citation needed ]
Scalp dysesthesia is characterized by pain or burning sensations on or under the surface of the cranial skin. Scalp dysesthesia may also present as excessive itching of the scalp. [ citation needed ]
Occlusal dysesthesia, or "phantom bite," is characterized by the feeling that the bite is "out of place" (occlusal dystopia) despite any apparent damage or instability to dental or oromaxillofacial structures or tissue. Phantom bite often presents in patients that have undergone otherwise routine dental procedures. Short of compassionate counseling, evidence for effective treatment regimes is lacking.
Chronic anxiety is often associated with dysesthesia due to extreme stress. [ 2 ] Patients with this anxiety may experience numbness or tingling in the face. In one study, those patients that were examined psychologically had symptoms of anxiety , depression , obsessive-compulsive personality disorder , or somatic symptom disorder . [ 3 ]
Although dysesthesia is similar to phantom limb syndrome, they should not be confused. In phantom limb, the sensation is present in an amputated or absent limb, while dysesthesia refers to discomfort or pain in a tissue that has not been removed or amputated. The dysesthetic tissue may also not be part of a limb, but part of the body, such as the abdomen. The majority of individuals with both phantom limb and dysesthesia experience painful sensations. [ citation needed ]
Phantom pain refers to dysesthetic feelings in individuals who are paralyzed or who were born without limbs. It is caused by the improper innervation of the missing limbs by the nerves that would normally innervate the limb. Dysesthesia is caused by damage to the nerves themselves, rather than by an innervation of absent tissue. [ citation needed ]
Dysesthesia should not be confused with anesthesia or hypoesthesia , which refer to a loss of sensation, or paresthesia which refers to a distorted sensation. Dysesthesia is distinct in that it can, but not necessarily, refer to spontaneous sensations in the absence of stimuli. In the case of an evoked dysesthetic sensation, such as by the touch of clothing, the sensation is characterized not simply by an exaggeration of the feeling, but rather by a completely inappropriate sensation such as burning.
Daily oral muscle physical therapy, or the administration of antidepressants have been reported as effective therapy for occlusal dysesthesia patients. [ 3 ] Tooth grinding, and the replacement or removal of all dental work should be avoided in patients with occlusal dysesthesia, [ 3 ] despite the frequent requests for further surgery often made by these patients.
Antidepressants are also often prescribed for scalp dysesthesia .
Prakash et al. found that many patients with burning mouth syndrome (BMS), one variant of occlusal dysesthesia, also report painful sensations in other parts of the body. Many of the patients with BMS met the classification of restless leg syndrome (RLS). About half of these patients also had a family history of RLS. These results suggest that some BMS symptoms may be caused by the same pathway as RLS in some patients, indicating that dopaminergic drugs regularly used to treat RLS may be effective in treating BMS as well.
There are a number of hypotheses regarding the basis of occlusal dysesthesia. Some researchers believe the disorder is a psychological one, while others believe it to be a psychosomatic disorder. [ 3 ] Joseph Marbach hypothesized that the symptoms were rooted in psychiatric disorders. Marbach suggested that occlusal dysesthesia would occur in patients with underlying psychological problems (such as schizophrenia) after having undergone dental treatment. More recently, two studies have found that occlusal dysesthesia is associated with somatoform disorders in which the patients obsess over the oral sensations.
Similarly, Marbach later proposed that occlusal dysesthesia may be caused by the brain “talking to itself,” causing abnormal oral sensations in the absence of external stimuli. According to this model, the symptoms of dysesthesia are catalyzed by dental “amputation,” for example the extraction of a tooth, whereby the brain loses the ability to distinguish between its memory of the bite and the actual, new bite. The patient, unable to recognize his or her own bite, becomes especially attentive to these perceived oral discrepancies. Finally and most recently, Greene and Gelb suggested that instead of having a psychological root, dysesthesia may be caused by a false signal being sent from the peripheral nervous system to the central nervous system. However, the reviewers note that no method exists for determining sensor nerve thresholds, and so sensory perception in the mouth is often measured by interdental thickness discrimination (ITD), or the ability to differentiate between the sizes of objects (thin blocks) placed between teeth. In one study, occlusal dysesthesia patients showed greater ability to differentiate these thicknesses than control, healthy individuals, but these differences were not statistically significant.
[ 14 ]
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Dysgraphia is a neurological disorder [ 2 ] and learning disability that concerns impairments in written expression, which affects the ability to write, primarily handwriting , but also coherence. It is a specific learning disability (SLD) as well as a transcription disability, meaning that it is a writing disorder associated with impaired handwriting, orthographic coding and finger sequencing (the movement of muscles required to write). [ 3 ] It often overlaps with other learning disabilities and neurodevelopmental disorders such as speech impairment , attention deficit hyperactivity disorder (ADHD) or developmental coordination disorder (DCD). [ 4 ]
In the Diagnostic and Statistical Manual of Mental Disorders ( DSM-5 ), dysgraphia is characterized as a neurodevelopmental disorder [ 5 ] under the umbrella category of specific learning disorder. [ 6 ] Dysgraphia is when one's writing skills are below those expected given a person's age measured through intelligence and age-appropriate education. The DSM is unclear in whether writing refers only to the motor skills involved in writing, or if it also includes orthographic skills and spelling. [ 4 ]
Dysgraphia should be distinguished from agraphia (sometimes called acquired dysgraphia) , which is an acquired loss of the ability to write resulting from brain injury , progressive illness, or a stroke . [ 7 ]
The word dysgraphia comes from the Greek words dys meaning "impaired" and γραφία graphía meaning "writing by hand". [ 3 ]
There are at least two stages in the act of writing: the linguistic stage and the motor-expressive- praxic stage. The linguistic stage involves the encoding of auditory and visual information into symbols for letters and written words. This is mediated through the angular gyrus , which provides the linguistic rules which guide writing. The motor stage is where the finger movements to write words or graphemes are articulated. This stage is mediated by Exner's writing area of the frontal lobe . [ 8 ]
The condition can cause individuals to struggle with feedback and anticipating and exercising control over rhythm and timing throughout the writing process. [ 9 ]
People with dysgraphia often write on some level and may experience difficulty with other activities requiring reciprocal movement of their fingers [ 9 ] and other fine motor skills , such as; tying shoes, fastening buttons or playing certain musical instruments. However, dysgraphia does not affect all fine motor skills. People with dysgraphia often have unusual difficulty with handwriting and spelling, [ 3 ] which in turn can cause writing fatigue. [ 4 ] Unlike people without transcription disabilities, they tend to fail to preserve the size and shape of the letters they produce if they cannot look at what they are writing. They may lack basic grammar and spelling skills (for example, having difficulties with the letters p, q, b, and d), and often will write the wrong word when trying to formulate their thoughts on paper. The disorder generally emerges when the child is first introduced to writing. [ 3 ] There is accumulating evidence that, in many cases, individuals with SLDs and DCD do not outgrow their disorders. [ 10 ] Accordingly, it has been found that adults, teenagers, and children alike are all subject to dysgraphia. [ 11 ] Studies have shown that higher education students with developmental dysgraphia still experience significant difficulty with hand writing, fine motor skills and motor-related daily functions when compared to their peers without neurodevelopmental disorders . [ 12 ]
Dysgraphia is nearly always accompanied by other learning disabilities and/or neurodevelopmental disorders such as dyslexia , attention deficit hyperactivity disorder , or oral and written language learning disability (OWL LD) [ 3 ] [ 13 ] and this can impact the type of dysgraphia a person has. Tourette syndrome , ASD and dyspraxia are also common diagnoses among dysgraphic individuals. [ 14 ] [ 15 ] [ 16 ] Developmental dysgraphia was originally described as being a disorder that occurs solely in dyslexic individuals. Dysgraphia was not studied as a separate entity until mid-20th century when researchers discovered there were different types that occur without dyslexia. [ 17 ] Dyslexics and dysgraphics experience similar synchronization difficulties and issues with spelling. However, dyslexia does not seem to impair physical writing ability or dramatically impact fine motor skills and dysgraphia does not impact reading comprehension . [ 4 ] Methods for evaluating, managing and remedying dysgraphia are still evolving, [ 17 ] but there are three principal subtypes of dysgraphia that are recognized.
There are several features that distinguish dyslexic-dysgraphia (sometimes called linguistic dysgraphia ) from the other types. People with dyslexic-dysgraphia typically have poor oral and written spelling that is typically phonemic in nature. Their spontaneously written work is often illegible, has extra or deleted syllables or letters, and contains unnecessary capitalization or large spaces in the middle of words which can make each individual word unrecognizable. They may also insert symbols that do not resemble any letter of the alphabet. Writing production generally requires long periods of contemplation and correction. [ 18 ]
Dyslexic-dysgraphic individuals have fairly good copied work, and their ability to draw is also preserved. Their finger tapping speed (a method for identifying fine motor problems) is normal, indicating that the deficit does not likely stem from cerebellar damage. [ 17 ] Impaired verbal executive functioning has also been related to this form of the disorder. [ 16 ]
One study found that boys with ADHD and dysgraphia struggle primarily with motor planning rather than have a linguistic impairment but the prevalence of linguistic/dyslexic-dysgraphia compared to other subtypes is uncertain. [ 4 ]
Motor dysgraphia (sometimes called peripheral dysgraphia ) [ 16 ] is due to deficient fine motor skills , poor dexterity, poor muscle tone or unspecified motor clumsiness. Motor dysgraphia impairs both motor patterns and motor memory. [ 9 ] Letter formation may be acceptable in very short samples of writing, but this requires extreme effort and an unreasonable amount of time to accomplish, and it cannot be sustained for a significant length of time, as it can cause arthritis -like tensing of the hand. Overall, their written work is poor to illegible even if copied by sight from another document, and drawing is impaired. Oral spelling for these individuals is normal, and their finger tapping speed is below normal. This shows that there are problems within the fine motor skills of these individuals. People with developmental coordination disorder may be dysgraphic and motor-dysgraphia may serve as a marker of dyspraxia. [ 19 ] Motor-dysgraphics struggle with proper finger grip and writing is often slanted due to holding a pen or pencil incorrectly. [ 3 ] [ 9 ] Average writing speed is slower than that of non-dysgrapic individuals, but this seems to improve with age. Motor skill deficits appears to be a common cause of dysgraphia; a study using digital tablets to measure various components of dysgraphic children's writing found that 78% of children with the disorder present kinematic difficulties, while 58% of them display issues with exerting pressure. [ 20 ]
A person with spatial dysgraphia has an impairment in the understanding of space. This impaired spatial perception causes illegible spontaneously written work, illegible copied work, abnormal spacing between letters and majorly impaired drawing abilities. They have normal oral spelling and normal finger tapping speed, suggesting that this subtype is not fine motor based. [ 16 ]
In 2010, the Dyscravia or voicing substitution dysgraphia subtype was proposed. [ 21 ] The subtype presents with differentiated voicing substitution, where individuals make mistakes when transferring from phonemes to graphemes (ie. "goat" would be mistakenly written as "coat"). Dyscravia does not appear to result from impairments in auditory processing or in speech production . It can occur with a completely intact graphemic buffer, phonological output lexicon , phonological output buffer, and allographic stage – the function that processes the voicing feature for writing may be selectively impaired without deficits in other functions of the conversion route. Dyscravia may or may not be accompanied by a parallel reading disability . [ 21 ]
In a 2012 study 19 of 90 patients, with primary progressive aphasia were found to meet diagnostic criteria for dyscravia, which is percentage-wise higher than in a normative population; 20% where as in a general population it is estimated at about 10%. [ 19 ] [ 22 ]
Other subtypes and informal classification systems have been proposed by researchers; this includes but is not limited to phonological dysgraphia, [ 23 ] deep dysgraphia and surface dysgraphia. [ 17 ] [ 15 ]
The symptoms to dysgraphia are often overlooked or attributed to the student being lazy, unmotivated, careless or anxious. The condition may also be dismissed as simply being an expression of attention deficiency or having delayed visual-motor processing. In order to be diagnosed with dysgraphia, one must have a cluster, but not necessarily all, of the following symptoms: [ 3 ] [ 9 ] [ 4 ]
The symptoms of dysgraphia can change as one ages. Dysgraphia may cause students distress often due to the fact that no one can read their writing, and they are aware that they are not performing to the same level as their peers. Emotional problems that may occur alongside dysgraphia include impaired self-esteem , lowered self-efficacy , reduced motivation, poorer social functioning, heightened anxiety , and depression . [ 3 ] [ 13 ] [ 9 ] [ 16 ] They may put in extra efforts in order to have the same achievements as their peers, but often get frustrated because they feel that their hard work does not pay off. [ 13 ] Dysgraphia is a hard disorder to detect as it does not affect specific ages, gender, or intelligence. [ 13 ] The main concern in trying to detect dysgraphia is that people hide their disability behind their verbal fluency/comprehension and strong syntax coding as a means to mask the handwriting impairments caused by the disorder. [ 13 ] Having dysgraphia is not related to a lack of cognitive ability , [ 3 ] and it is not uncommon in intellectually gifted individuals, but due to dysgraphia their intellectual abilities are often not identified. [ 13 ]
There are some common problems not related to dysgraphia but often associated with dysgraphia, the most common of which is stress. Developing an aversion to writing is another common issue. Often children (and adults) with dysgraphia will become extremely frustrated with the task of writing specially on plain paper (and spelling); younger children may cry, pout, or refuse to complete written assignments. This frustration can cause the individuals a great deal of stress and can lead to stress-related illnesses. This can be a result of any symptom of dysgraphia. [ 9 ] [ 11 ] [ 13 ]
The underlying causes of the disorder are not fully understood, [ 15 ] but dysgraphia is known to have genetic causes. [ 3 ] More specifically, it is a working memory problem [ 13 ] caused by specific neurodevelopmental dysfunction. [ 9 ] In dysgraphia, individuals fail to develop normal connections among different brain regions needed for writing. [ 13 ] People with dysgraphia have difficulty in automatically remembering and mastering the sequence of motor movements required to write letters or numbers. [ 3 ] Dysgraphia is also in part due to underlying problems in orthographic coding, the orthographic loop, and graphomotor output (the movements that result in writing) by one's hands, fingers and executive functions involved in letter writing. [ 3 ] The orthographic loop is when written words are stored in the mind's eye, connected through sequential finger movement for motor output through the hand with feedback from the eye. [ 13 ]
Family history of specific learning disabilities may play a role. Children with developmental dysphasia , developmental dysgraphia and developmental dyslexia may be more likely to have family members with one of these conditions. [ 15 ] Genetic studies suggest that verbal executive function tasks, orthographic skills, and spelling ability may have a genetic basis. Genes on chromosomes 6 and 15 may play some role with SLDs as they have linked to poorer reading, poorer spelling and lower phonemic awareness. [ 16 ]
Unlike specific learning disabilities and neurodevelopmental disorders that have been more extensively studied, there is no gold standard for diagnosing dysgraphia. This is likely due to writing systems often differing substantially between countries and languages and there being considerable heterogeneity among medical professionals who are charged with diagnosing dysgraphia. Consequently, there are several tests that are used to diagnose dysgraphia like Ajuriaguerra scale, BHK for children or teenagers, the Minnesota Handwriting Assessment, ETCH, SCRIPT, DASH and HHE scale. [ 25 ] [ 26 ]
With devices like drawing tablets , it is now possible to measure the position, tilt, and pressure in real time. From these features, it is possible to compute automatic features like speed and shaking and train a classifier to diagnose automatically children with atypical writing. [ 25 ] The features extracted have different importances in the classification through development and allow to characterize different subtypes of dysgraphia that could have different origins, outcomes and could require different remediation strategies. [ 27 ]
It is not uncommon for dysgraphic individuals to be intellectually gifted, possess a rich vocabulary and have strong comprehension of language when speaking or reading, though their disorder is often not detected or treated; which may also be in part to developmental dyslexia receiving far more academic and medical attention than developmental dysgraphia. [ 28 ] In addition, gifted children with transcription disabilities seldom receive programming for their intellectual talents due to their difficulties in completing written assignments. [ 3 ]
Treatment for dysgraphia varies and may include treatment for motor disorders to help control writing movements. Helping dysgraphic students overcome writing avoidance and accept the purpose and necessity of writing may be needed. [ 9 ] The use of occupational therapy can be effective in the school setting, and teachers should be well informed about dysgraphia to aid in carry-over of the occupational therapist's interventions. One common form of therapy is the use of Thera-putty, which helps develop dexterity. Treatments may address impaired memory or other neurological problems. Some physicians recommend that individuals with dysgraphia use computers to avoid the problems of handwriting. Speech-to-text programs have also been suggested as a potential treatments for dysgraphia. Speech-recognition technologies are used in two ways: dictation and computer control. As a dictation tool, spoken words are translated into written text; the student speaks the words into a microphone and the words are typed. The computer-control tool allows students to control the computer and software applications by speaking commands. If students are going to use speech-recognition software, they need to use consistent, clear speech. The use of computers also allows patients to experiment with different ergonomic keyboards. Today, there are many alternative keyboards for consideration. There are keyboards with enlarged and/or alphabetically arranged letters; there are key boards that are ergonomically designed; and there are mini keyboards for students who have a limited range of motion. Dysgraphia can sometimes be partially overcome with appropriate and conscious effort and training. [ 3 ]
It has been estimated that up to 10% of children in the world are affected by disabilities like dysgraphia, dyslexia, dyscalculia and dyspraxia. [ 19 ] [ 29 ]
There is no special education category for students with dysgraphia; [ 3 ] in the United States, The National Center for Learning Disabilities suggests that children with dysgraphia be handled in a case-by-case manner with an Individualized Education Program , or provided individual accommodation to provide alternative ways of submitting work and modify tasks to avoid the area of weakness. (It can often be difficult for students to have general accommodations for any student that might have dysgraphia as "Careful planning should precede all technology purchases, as many technologies are costly and school budgets are limited. In considering adoption of any of the technology recommended") [ United States-centric ] [ 11 ] Students with dysgraphia often cannot complete written assignments that are legible, appropriate in length and content, or within given time. [ 3 ] It is suggested that students with dysgraphia receive specialized instructions that are appropriate for them. Children will mostly benefit from explicit and comprehensive instructions, help translating across multiple levels of language, and review and revision of assignments or writing methods. [ 13 ] Direct, explicit instruction on letter formation and guided practice will help students achieve automatic handwriting performance before they use letters to write words, phrases, and sentences. [ 3 ] Some older children may benefit from the use of a personal computer or a laptop in class so that they do not have to deal with the frustration of falling behind their peers. [ 13 ] Predictive text technology has been suggested as something that could greatly help students with dysgraphia. [ 30 ]
It is also suggested by Berninger that teachers with dysgraphic students decide if their focus will be on manuscript writing (printing) or keyboarding . In either case, it is beneficial that students are taught how to read cursive writing as it is used daily in classrooms by some teachers. [ 3 ] It may also be beneficial for the teacher to come up with other methods of assessing a child's knowledge other than written tests; an example would be oral testing. This causes less frustration for the child as they are able to get their knowledge across to the teacher without worrying about how to write their thoughts. [ 11 ] Dysgraphic students may benefit from special accommodation by their teachers when being required to write. Accommodations that may be helpful include but are not limited to; offering larger pencils or pencils with special grips, supplying paper with raised lines to provide tactile feedback, allowing extra time for classwork assignments, scaling down large written assignments and breaking down long written assignments into multiple shorter assignments. [ 16 ]
The number of students with dysgraphia may increase from 4 percent of students in primary grades, due to the overall difficulty of handwriting, and up to 20 percent in middle school because written compositions become more complex. With this in mind, there are no exact numbers of how many individuals have dysgraphia due to its difficulty to diagnose [ 3 ] and exact prevalence depends on the definition of dysgraphia. There are slight gender differences in association with written disabilities; overall it is found that males are more likely to be impaired with handwriting, composing, spelling, and orthographic abilities than females. [ 13 ] [ 16 ]
The Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) does not use the term dysgraphia but uses the phrase "an impairment in written expression" under the category of "specific learning disorder". This is the term used by most doctors and psychologists. To qualify for special education services, a child must have an issue named or described in the Individuals with Disabilities Education Act (IDEA). [ United States-centric ] While IDEA does not use the term "dysgraphia", it describes it under the category of "specific learning disability". [ United States-centric ] This includes issues with understanding or using language (spoken or written) that make it difficult to listen, think, speak, read, write, spell or to do mathematical calculations. [ citation needed ]
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Dyskinesia refers to a category of movement disorders that are characterized by involuntary muscle movements, [ 1 ] including movements similar to tics or chorea and diminished voluntary movements. [ 2 ] Dyskinesia can be anything from a slight tremor of the hands to an uncontrollable movement of the upper body or lower extremities. Discoordination can also occur internally especially with the respiratory muscles and it often goes unrecognized. [ 3 ] Dyskinesia is a symptom of several medical disorders that are distinguished by their underlying causes.
Acute dystonia is a sustained muscle contraction that sometimes appears soon after administration of antipsychotic medications. [ 4 ] Any muscle in the body may be affected, including the jaw, tongue, throat, arms, or legs. When the throat muscles are involved, this type of dystonia is called an acute laryngospasm and is a medical emergency because it can impair breathing. [ 4 ] Older antipsychotics such as haloperidol or fluphenazine are more likely to cause acute dystonia than newer agents. Giving high doses of antipsychotics by injection also increases the risk of developing acute dystonia. [ 4 ]
Methamphetamine , other amphetamines and dopaminergic stimulants including cocaine and pemoline can produce choreoathetoid dyskinesias; the prevalence, time-frame and prognosis are not well established. Amphetamines also cause a dramatic increase in choreoathetoid symptoms in patients with underlying chorea such as Sydenham's , Huntington's , and lupus . [ 5 ] Long-term use of amphetamines may increase the risk of Parkinson's disease (PD) : in one retrospective study with over 40,000 participants it was concluded that amphetamine abusers generally had a 200% higher chance of developing PD versus those with no history of abuse; the risk was much higher in women, almost 400%. [ 6 ] There remains some controversy as of 2017. [ 7 ] [ relevant? ]
Levodopa-induced dyskinesia (LID) is evident in patients with Parkinson's disease who have been on levodopa ( L ‑DOPA) for prolonged periods of time. LID commonly first appears in the foot, on the most affected side of the body. There are three main types that can be classified on the basis of their course and clinical presentation following an oral dose of L ‑DOPA: [ 8 ] [ 9 ]
Late-onset dyskinesia, also known as tardive dyskinesia , occurs after long-term treatment with an antipsychotic drug such as haloperidol (Haldol) or amoxapine (Asendin). The symptoms include tremors and writhing movements of the body and limbs, and abnormal movements in the face, mouth, and tongue – including involuntary lip smacking, repetitive pouting of the lips, and tongue protrusions. [ 11 ]
Rabbit syndrome is another type of chronic dyskinesia, while orofacial dyskinesia may be related to persistent replication of herpes simplex virus type 1 . [ 12 ]
Two other types, primary ciliary dyskinesia and biliary dyskinesia , are caused by specific kinds of ineffective movement of the body, and are not movement disorders .
Antidyskinetic drugs can be used to treat dyskinesia. [ 13 ] [ 14 ] [ 15 ] Certain anticonvulsants can be used as antidyskinetic agents, among drugs acting at other targets . [ 13 ] [ 15 ] Amantadine is approved for treatment of levodopa-induced dyskinesia . [ 16 ] Dopamine-depleting agents like tetrabenazine , deutetrabenazine , and valbenazine are used to treat tardive dyskinesia . [ 17 ]
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Dyslalia is an antiquated term for the incapacity to produce speech phonetically correctly, without neurological disorders or hearing disorders . Under the ICD-10, Dyslalia is currently coded under F80.0 (Phonological disorder). See speech disorders for information on current classifications and etiologies of phonetically based speech sound disorders.
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Dysmorphopsia , in a broad sense, is a condition in which a person is unable to correctly perceive objects. It is a visual distortion , used to denote a variant of metamorphopsia in which lines appear wavy. [ 1 ] These illusions may be restricted to certain visuals areas, or may affect the entire visual field. [ 2 ]
It has been associated with meningioma tumors [ 3 ] and bilateral lateral occipital cortical damage, e.g. after carbon monoxide poisoning or drug abuse . [ 4 ]
The term dysmorphopsia comes from the Greek words dus (bad), morphè (form) and opsis (seeing). [ 1 ]
This article about a medical condition affecting the nervous system is a stub . You can help Wikipedia by expanding it .
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In medicine , dysthanasia occurs when a person who is dying has their biological life extended through technological means without regard to the person's quality of life . [ 1 ] The term dysthanasia means "bad death" (from the Greek language : δυσ, dus ; "bad", "difficult" + θάνατος, thanatos ; "death") [ 2 ] and is considered by some to be a common fault of modern medicine . [ 3 ] Technologies such as an implantable cardioverter defibrillator , [ 4 ] artificial ventilation , ventricular assist devices , and extracorporeal membrane oxygenation can extend the dying process. In some cases, cardiopulmonary resuscitation can be considered a form of dysthanasia. [ 5 ] [ 6 ]
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Dystrophy is the degeneration of tissue , due to disease or malnutrition , most likely due to heredity .
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An e-patient is a health consumer who participates fully in their own medical care , primarily by gathering information about medical conditions that impact them and their families, using the Internet and other digital tools. [ 1 ] The term encompasses those who seek guidance for their own ailments, and the friends and family members who research on their behalf. E-patients report two effects of their health research: "better health information and services, and different, but not always better, relationships with their doctors." [ 2 ]
E-patients are active in their care and demonstrate the power of the participatory medicine or Health 2.0 / Medicine 2.0. [ 3 ] model of care. The "e" can stand for " electronic " but has also been used to refer to other terms, such as "equipped", "enabled", "empowered" and "expert". [ 4 ] [ 5 ]
The current state of knowledge on the impact of e-patients on the healthcare system and the quality of care received indicates:
A 2011 study of European e-patients found that they tended to be "inquisitive and autonomous" and that they noted that the number of e-patients in Europe appeared to be rising. [ 13 ] A 2012 study found that e-patients uploading videos about their health experienced a loss of privacy, but also positive benefits from social support . [ 14 ] A later 2017 study utilizing social network analysis found that when e-patients are included in health care conferences, they increase information flow, expand propagation, and deepen engagement in the conversation of tweets when compared to both physicians and researchers while only making up 1.4% of the stakeholder mix. [ 15 ]
According to Maho Isono, PhD, at the International University of Health and Welfare in Ōtawara , Japan, the term closest to e-patient in Japanese is tojisha-kenkyu , where " kenkyu means study, investigation and research" and " tojisha refers to interested persons, disabled persons themselves or patients themselves." [ 16 ]
Inspired by the seminal work on e-patients by Tom Ferguson and the e-Patients Scholars Working Group, [ 17 ] Swedish patient and engineer Sara Riggare [ sv ] coined a new Swedish word, " spetspatient ", meaning "lead user patient" or "lead patient", in February 2016.
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The E.B. Wilson Medal is the American Society for Cell Biology 's highest honor for science and is presented at the Annual Meeting of the Society for significant and far-reaching contributions to cell biology over the course of a career. It is named after Edmund Beecher Wilson . [ 1 ]
Source : ASCB
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Edward Francis Bani Forster , FRSA , FWACP , was a Gambian physician and academic based in Ghana . He was the first Gambian psychiatrist, and a professor of Psychiatry at the University of Ghana . He served as the president of the West African College of Physicians from 1983 to 1984.
Forster was a foundation member of the Medical Research Council of Psychiatry, and a foundation fellow of the West African College of Physicians. He was a fellow of the Royal Society of Arts , [ 1 ] a member of the Association for the Advancement of Psychotherapy , USA, a member of the Royal College of Psychiatry , and a member of the Association of Psychiatrists of Africa. [ 2 ]
Forster was born on 16 December 1917 in Banjul , Gambia . He had his early education at the St. Mary's Primary School in Banjul, Gambia from 1923 to 1932. In 1932, he was enrolled at Church Missionary Society Grammar School in Freetown , Sierra Leone , for his secondary education and graduated in 1937. [ 2 ] That year he entered Trinity College, Dublin , Ireland , [ 3 ] [ 4 ] where he obtained his Licentiate of Medicine in 1943, and his Diploma in Psychological Medicine in 1950. [ 5 ] [ 6 ] [ 7 ] He subsequently qualified as a member of the Royal College of Physicians , and a member of the British Medical Association . [ 7 ]
Forster began his career as a house surgeon at the Birmingham Accident Hospital , in the West Midlands of England, in 1943. In 1944, he joined Warlingham Park Mental Hospital as a house physician. [ 2 ] That same year, he was appointed assistant medical officer at the Central Mental Hospital in Hatton. [ 2 ] He worked there for about two years, after which he was made a general practitioner in Birmingham , England. Forster returned to Gambia in 1946 and served under the colonial medical services until 1951. [ 7 ] [ 8 ] He joined the Ministry of Health in Accra , [ 9 ] Ghana where he worked as a consultant in Psychiatry and later, doctor in charge of the Accra Mental Hospital. [ 10 ] [ 11 ] [ 12 ] He served in this capacity until 1970 when he gained employment at the University of Ghana . [ 2 ]
After serving for about 19 years as the doctor in charge of the Accra Mental Hospital, Forster was appointed associate professor of Psychiatry at the University of Ghana Medical School . In 1972, he was elevated to the status of a professor and head of the Psychiatry Department of the University of Ghana Medical School. [ 2 ] [ 6 ] [ 12 ] [ 13 ] He was president of the West African College of Physicians from 1983 to 1984.
Forster was a recipient of the Grand Medal of Ghana in 1973. [ 2 ]
Forster was the son of Hannah Forster; the first Gambian female politician, and the brother of Catherine Collier; the first Gambian Radiographer . [ 14 ] He married Essi Matilda Forster ( née Christian, who was the first female Gold Coast native to become a lawyer) on 17 December 1944. [ 12 ] Together, they had three children: one daughter and two sons. [ 2 ] Forster's hobbies were walking, and reading. [ 2 ]
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The E. Mead Johnson Award , given by the Society for Pediatric Research , was established in 1939 to honor clinical and laboratory research achievements in pediatrics . The awards are funded by Mead Johnson Nutritionals , a subsidiary of Reckitt Benckiser and are named after Edward Mead Johnson , a co-founder of the originating company Johnson & Johnson . [ 1 ] Two researchers sometimes share a prize.
Source: [ 2 ]
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The ELVIS Procedure is a hybrid endoscopic and laparoscopic operation for evaluation of the colon . ELVIS stands for e ndoscopic/ l aparoscopic vis ualisation. This procedure is utilized for patients in whom a standard colonoscopy was unable to be completed. This is also found in the surgical literature as a "laparoscopic-assisted endoscopy" and has been described since 1992. [ 1 ]
This typically is associated with anatomic issues such as a redundant sigmoid colon or a transverse colon which prevents complete advancement of the colonoscope to the cecum . During an ELVIS procedure one proceduralist attempts a standard colonoscopy in the operating room with the patient under anesthesia. At the same time, a surgeon introduces laparoscopic ports into the patient's abdomen . Typically one or two ports are necessary. Through one port a laparoscope is introduced (usually through a 12 mm port in the umbilicus) and another port is used for introduction of a laparoscopic instrument, such as a grasper. As the colonoscopy is being performed the laparoscopic instruments are utilized to position the colon as needed to assist with advancement of the colonoscope. This is accomplished by placing counter pressure where the scope is turning or holding the colon in a way to reduce angulation.
The benefit is that a more aggressive technique may be employed to resect a colonic mass or polyp : An injury such as a perforation would be visualized and a repair could be attempted laparoscopically immediately.
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The ESC Congress is the annual congress of the European Society of Cardiology (ESC), the largest medical congress in Europe. It gathers over 30,000 active participants (mainly cardiologists) and takes place every year in August/September in a different European city. [ citation needed ]
The first ESC Congress was held in 1950 and from then on every 4 years [ 1 ] until 1988, when it became an annual event.
After the 2017 ESC Congress, Barcelona became the city with most congresses since 1988(6), followed by Stockholm (5) and then by Amsterdam and Vienna and Munich (4 times each as of 2018).
Some congresses (1994, 2006 and 2019) were organised jointly with the World Heart Federation [ 2 ] under the name of "World Congress of Cardiology".
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ESKAPE is an acronym comprising the scientific names of six highly virulent and antibiotic resistant bacterial pathogens including: Enterococcus faecium , Staphylococcus aureus , Klebsiella pneumoniae , Acinetobacter baumannii , Pseudomonas aeruginosa , and Enterobacter spp. [ 1 ] The acronym is sometimes extended to ESKAPEE to include Escherichia coli . [ 2 ] This group of Gram-positive and Gram-negative bacteria can evade or 'escape' commonly used antibiotics due to their increasing multi-drug resistance (MDR). [ 1 ] As a result, throughout the world, they are the major cause of life-threatening nosocomial or hospital-acquired infections in immunocompromised and critically ill patients who are most at risk. [ 3 ] P. aeruginosa and S. aureus are some of the most ubiquitous pathogens in biofilms found in healthcare. [ 4 ] P. aeruginosa is a Gram-negative, rod-shaped bacterium, commonly found in the gut flora, soil, and water that can be spread directly or indirectly to patients in healthcare settings. [ 5 ] [ 6 ] The pathogen can also be spread in other locations through contamination, including surfaces, equipment, and hands. The opportunistic pathogen can cause hospitalized patients to have infections in the lungs (as pneumonia), blood, urinary tract, and in other body regions after surgery. [ 6 ] S. aureus is a Gram-positive, cocci-shaped bacterium, residing in the environment and on the skin and nose of many healthy individuals. [ 7 ] The bacterium can cause skin and bone infections, pneumonia, and other types of potentially serious infections if it enters the body. S. aureus has also gained resistance to many antibiotic treatments, making healing difficult. [ 7 ] Because of natural and unnatural selective pressures and factors, antibiotic resistance in bacteria usually emerges through genetic mutation or acquires antibiotic-resistant genes (ARGs) through horizontal gene transfer - a genetic exchange process by which antibiotic resistance can spread. [ 8 ]
One of the main reasons for the rise in the selection for antibiotic resistance (ABR) and MDR which led to the emergence of the ESKAPE bacteria is from the rash overuse of antibiotics not only in healthcare, but also in the animal, and agricultural sector. [ 9 ] Other key factors include misuse and inadequate adherence to treatment guidelines. [ 10 ] Due to these factors, fewer and fewer antibiotic treatments are effective in eradicating ABR and MDR bacterial infections, while at the same time there are now no new antibiotics being created due to lack of funding. [ 10 ] These ESKAPE pathogens, along with other antibiotic-resistant bacteria, are an interweaved global health threat and are being addressed from a more holistic and One Health perspective. [ 6 ] [ 9 ]
From a global perspective, the emergence of multidrug-resistant (MDR) bacteria is responsible for about 15.5% of hospital acquired infection cases and there are currently about 0.7 million deaths from drug-resistant disease. [ 1 ] [ 11 ] Specifically, the opportunistic nosocomial ESKAPE pathogens correspond with the highest risk of mortality which has the majority of its isolates being MDR. [ 12 ] Two pathogens within the ESKAPE group, Carbapenem-resistant Acinetobacter and Carbapenem-resistant Enterobacteriaceae are currently in the top five of the antibiotic resistant bacteria on the CDC's 2019 urgent threat list, and the other 4 pathogens making up the group are on the serious threat list. [ 6 ] In addition, the World Health Organization (WHO) created a global priority pathogen list (PPL) of ABR bacteria with the goal to prioritize research and create new effective antibiotic treatments. [ 13 ] The global PPL classifies pathogens into 3 categories, critical, high, and medium, and has 4 of the pathogens from the ESKAPE group in the critical priority list and the other 2 pathogens that make up the group in the high priority list. [ 13 ]
ESKAPE pathogens are differentiated from other pathogens due to their increased resistance to commonly used antibiotics such as penicillin , vancomycin , carbapenems , and more. This increased resistance, combined with the clinical significance of these bacteria in the medical field, results in a necessity to understand their mechanisms of resistance and combat them with novel antibiotics. Common mechanisms for resistance include the production of enzymes that attack the structure of antibiotics (for example, β-lactamases inactivating β-lactam antibiotics), modification of the target site that the antibiotic targets so that it can no longer bind properly, efflux pumps, and biofilm production. [ 5 ] Efflux pumps are a feature of the membrane of Gram-negative bacteria that allows them to constantly pump out foreign material, including antibiotics, so that the inside of the cell never contains a high enough concentration of the drug to have an effect. [ 5 ] Biofilms are a mixture of diverse microbial communities and polymers that protect the bacteria from antibiotic treatment by acting as a physical barrier. [ 5 ]
Due to their heightened resistance to frequently used antibiotics, these pathogens pose an additional threat to the safety of the general population, particularly those who frequently interact with hospital environments, as they most commonly contribute to hospital-acquired infections (HAI) . The increased antimicrobial resistance profile of these pathogens varies, however they arise from similar causes. One common cause of antibiotic resistance is due to incorrect dosing. When a sub-therapeutic dose is prescribed, or a patient chooses to use less of their prescribed antibiotic, bacteria are given the opportunity to adapt to the treatment. At lower doses, or when a course of antibiotics is not completed, certain strains of the bacteria develop drug-resistant strains through the process of natural selection. [ 14 ] This is due to the random genetic mutations that are constantly occurring in many forms of living organisms, bacteria and humans included. Natural selection supports the persistence of strains of bacteria that have developed a certain mutation that allows them to survive. Some strains are also able to participate in inter-strain horizontal gene transfer , allowing them to pass resistance genes from one pathogen to another. [ 14 ] This can be particularly problematic in nosocomial infections, where bacteria are constantly exposed to antibiotics and those benefiting from resistance as a result of random genetic mutations can share this resistance with bacteria in the area that have not yet developed this resistance on their own.
Enterococcus faecium is a Gram-positive sphereically shaped ( coccus ) bacteria that tends to occur in pairs or chains, most commonly involved in HAI in immunocompromised patients. It often exhibits a resistance to β-lactam antibiotics including penicillin and other last resort antibiotics. [ 14 ] There has also been a rise in vancomycin resistant enterococci (VRE) strains, including an increase in E. faecium resistance to vancomycin, particularly vancomycin-A. [ 14 ] These vancomycin-resistant strains display a profound ability to develop and share their resistance through horizontal gene transfer, as well as code for virulence factors that control phenotypes. These virulence phenotypes range from thicker biofilms to allowing them to grow in a variety of environments including medical devices such as urinary catheters and prosthetic heart valves within the body. [ 15 ] The thicker biofilms act as a “mechanical and biochemical shield” that protects the bacteria from the antibiotics and are the most effective protective mechanism that bacteria have against treatment. [ 5 ]
Staphylococcus aureus is a Gram-positive round-shaped ( coccus ) bacteria that is commonly found as a part of the human skin microbiota and is typically not harmful in humans with non-compromised immune systems in these environments. However, S. aureus has the ability to cause infections when it enters parts of the body that it does not typically inhabit, such as wounds. Similar to E. faecium , S. aureus can also cause infections on implanted medical devices and form biofilms that make treatment with antibiotics more difficult. [ 14 ] Additionally, approximately 25% of S. aureus strains secrete the TSST-1 exotoxin responsible for causing toxic shock syndrome . [ 14 ] Methicillin-resistant S. aureus , or MRSA , includes strains distinct from other strains of S. aureus in the fact that they have developed resistance to β-lactam antibiotics . Some also express an exotoxin that has been known to cause “necrotic hemorrhagic pneumonia” in those with an infection. [ 14 ] Vancomycin and similar antibiotics are typically the first choices for treatment of MRSA infections, however from this vancomycin-resistant S. aureus , or VRSA (VISA for those with intermediate resistance) strains have emerged. [ 14 ]
Klebsiella pneumoniae is a Gram-negative rod-shaped ( bacillus ) bacteria that is particularly adept to accepting resistance genes in horizontal gene transfer. It is commonly also resistant to phagocyte treatment due to its thick biofilm with strong adhesion to neighboring cells. [ 14 ] Certain strains have also developed β-lactamases that allow them to be resistant many of the commonly used antibiotics, including carbapenems , which has led to the creation of carbapenem-resistant K. pneumoniae (CRKP), for which there are very few antibiotics in development that can treat infection. [ 14 ]
Acinetobacter baumannii is most common in hospitals, which has allowed for the development of resistance to all known antimicrobials. The Gram-negative short-rod-shaped ( coccobacillus ) A. baumannii thrives in a number of unaccommodating environments due to its tolerance to a variety of temperatures, pHs , nutrient levels, as well as dry environments. [ 14 ] The Gram-negative aspects of the membrane surface of A. baumannii, including the efflux pump and outer membrane, affords it a wider range of antibiotic resistance. [ 14 ] Additionally, some problematic A. baumannii strains are able to acquire families of efflux pumps from other species, and are commonly first to develop new β-lactamases to improve β-lactam resistance. [ 14 ]
The Gram-negative, rod-shaped ( bacillus ) bacterium Pseudomonas aeurginosa is ubiquitous hydrocarbon degrader that is able to survive in extreme environments as well as in soil and many more common environments. Because of this versatility, it survives quite well in the lungs of patients with late-stage cystic fibrosis (CF). [ 14 ] It also benefits from the same previously mentioned Gram-negative resistance factors as A. baumannii. Mutants of P. aeruginosa with upregulated efflux pumps also exist that make finding an effective antibiotic or detergent incredibly difficult. [ 14 ] There are also some multi-drug resistant (MDR) strains of P. aeruginosa that express β-lactamases as well as upregulated efflux pumps which can make treatment particularly difficult. [ 14 ]
Enterobacter encompasses a family of Gram-negative , rod-shaped ( bacillus ) species of bacteria. Some strains cause urinary tract (UTI) and blood infections and are resistant to multiple drug therapies, which therefore puts the human population in critical need for the development of novel and effective antibiotic treatments. [ 16 ] Colistin and tigecycline are two of the only antibiotics currently used for treatment, and there are seemingly no other viable antibiotics in development. [ 14 ] In some Enterobacter species, a 5–300-fold increase in minimum inhibitory concentration was observed when exposed to several gradually increasing concentrations of benzalkonium chloride (BAC) . [ 17 ] Other Gram-negative bacteria (including Enterobacter , but also Acinetobacter, Pseudomonas, Klebsiella species, and more) also displayed a similar ability to adapt to the disinfectant BAC. [ 17 ]
The ESKAPE pathogens and ABR bacteria in general are an interconnected global health threat and a clear ' One Health ' problem, meaning they can spread between and impact the environment, animal, and human sectors. [ 18 ] As one of the largest global health challenges, combatting the highly resistant and opportunistic ESKAPE pathogens necessitates a One Health approach. [ 12 ] One Health is a transdisciplinary approach that involves addressing health outcomes from a multifaceted and interdisciplinary perspective for humans, animals, and the environmental on a local, national, and global level. [ 9 ] Using this framework and mindset is crucial to combat and prevent the spread and development of the ESKAPE pathogens (including the ABR in general) while addressing its importantly related socioeconomic factors, such as inadequate sanitation. [ 9 ] New treatment alternatives for infections caused by ESKAPE are under current scientific research. [ 19 ]
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Eagle syndrome (also termed stylohyoid syndrome , [ 1 ] styloid syndrome , [ 2 ] stylalgia , [ 3 ] styloid-stylohyoid syndrome , [ 2 ] or styloid–carotid artery syndrome ) [ 4 ] is an uncommon condition commonly characterized but not limited to sudden, sharp nerve-like pain in the jaw bone and joint , back of the throat , and base of the tongue, triggered by swallowing, moving the jaw, or turning the neck. [ 1 ] First described by American otorhinolaryngologist Watt Weems Eagle in 1937, [ 5 ] the condition is caused by an elongated or misshapen styloid process (the slender, pointed piece of bone just below the ear) and/or calcification of the stylohyoid ligament , either of which interferes with the functioning of neighboring regions in the body, such as the glossopharyngeal nerve . [ 5 ]
Possible symptoms include:
Classic Eagle syndrome is present on only one side; however, it may rarely be present on both sides. [ 6 ]
In vascular Eagle syndrome, the elongated styloid process comes in contact with the internal carotid artery below the skull. In these cases, turning the head can cause compression of the artery or a tear inside the blood vessel , which restricts blood flow and can potentially lead to a transient ischemic attack or stroke . [ 6 ] Sometimes, compression of the internal jugular vein can also occur and might lead to increased intracranial pressure . [ 8 ] [ 9 ] [ 10 ]
Eagle syndrome occurs due to elongation of the styloid process or calcification of the stylohyoid ligament, potentially compressing the nearby carotid artery or glossopharyngeal nerve. [ 5 ] However, the cause of the elongation hasn't been known clearly. It could occur spontaneously or could arise since birth. Usually normal stylohyoid process is 2.5–3 cm in length, if the length is longer than 3 cm, it is classified as an elongated stylohyoid process. [ 11 ] There are reports of eagles syndrome been elicited after wisdom tooth removal. [ 12 ]
Diagnosis is suspected when a patient presents with the symptoms of the classic form of "Eagle syndrome" e.g. unilateral neck pain, sore throat or tinnitus. Sometimes the tip of the styloid process is palpable in the back of the throat. The diagnosis of the vascular type is more difficult and requires an expert opinion. One should have a high level of suspicion when neurological symptoms occur upon head rotation. Symptoms tend to be worsened on bimanual palpation of the styloid through the tonsillar bed. They may be relieved by infiltration of lidocaine into the tonsillar bed. Because of the proximity of several large vascular structures in this area this procedure should not be considered to be risk free.
Imaging is important and is diagnostic. Visualizing the styloid process on a CT scan with 3D reconstruction is the suggested imaging technique. [ 13 ] The enlarged styloid may be visible on an orthopantogram or a lateral soft tissue X ray of the neck.
Treatment for Eagle Syndrome varies by case severity. Conservative methods typically include physiotherapy, long-acting anesthetics, and anti-inflammatory drugs. [ 14 ] More specifically NSAIDs , anticonvulsants , and antidepressants . NSAIDs are beneficial for inflammatory symptoms, while other medications target nerve-related pain.
Studies have shown that consistent physical therapy can significantly reduce pain and improve quality of life for patients with Eagle Syndrome. [ 14 ] Physical therapy aims to reduce overall pain by relaxing muscles around the calcified styloid ligament. Techniques may include manual therapy , stretching exercises, and specific movements to alleviate tension and improve muscle function.
A partial styloidectomy is the preferred approach. Repair of a damaged carotid artery is essential in order to prevent further neurological complications. [ citation needed ] Regrowth of the stylohyoid process and relapse being a common occurrence is debatable. [ 7 ] Medical management may include the use of pain and anti-inflammatory medications, antidepressants , and/or corticosteroids . The overall success rate for treatment (medical or surgical) is about 80%. [ 15 ]
Approximately 4% of the general population have an elongated styloid process, and of these about 4% give rise to the symptoms of Eagle syndrome. [ 5 ] Therefore, the incidence of stylohyoid syndrome may be about 0.16%. [ 5 ] More recent studies have reported the incidence of styloid elongation to be as high as 54%. [ 16 ]
Patients with this syndrome tend to be between 30 and 50 years of age but it has been recorded in teenagers and in patients > 75 years old. It is more common in women, with a male:female ratio ~ 1:2. [ citation needed ]
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The ear canal ( external acoustic meatus , external auditory meatus , EAM ) is a pathway running from the outer ear to the middle ear . The adult human ear canal extends from the auricle to the eardrum and is about 2.5 centimetres (1 in) in length and 0.7 centimetres (0.3 in) in diameter.
The human ear canal is divided into two parts. The elastic cartilage part forms the outer third of the canal; its anterior and lower wall are cartilaginous, whereas its superior and back wall are fibrous. The cartilage is the continuation of the cartilage framework of auricle. The cartilaginous portion of the ear canal contains small hairs and specialized sweat glands, called apocrine glands, which produce cerumen ( ear wax ). The bony part forms the inner two thirds. The bony part is much shorter in children and is only a ring ( annulus tympanicus ) in the newborn. The layer of epithelium encompassing the bony portion of the ear canal is much thinner and therefore, more sensitive in comparison to the cartilaginous portion.
Size and shape of the canal vary among individuals. The canal is approximately 2.5 centimetres (1 in) long and 0.7 centimetres (0.28 in) in diameter. [ 2 ] It has a sigmoid form and runs from behind and above downward and forward. On the cross-section, it is of oval shape. These are important factors to consider when fitting earplugs .
Due to its relative exposure to the outside world, the ear canal is susceptible to diseases and other disorders. Some disorders include:
Earwax, also known as cerumen, is a yellowish, waxy substance secreted in the ear canals. It plays an important role in the human ear canal, assisting in cleaning and lubrication, and also provides some protection from bacteria , fungi , and insects . Excess or impacted cerumen can press against the eardrum and/or occlude the external auditory canal and impair hearing, causing conductive hearing loss . If left untreated, cerumen impaction can also increase the risk of developing an infection within the ear canal.
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Earl Emanuel Shepard (September 1908 – May 1991) was an American orthodontist who is known for his contributions in the field of orthodontics. [ 1 ] He was director of the American Board of Orthodontics for 10 years. American Association of Orthodontics has an award named after Shepard which is given every year to orthodontists who have shown distinguished service in the field of orthodontics. [ 2 ]
He was born in Marine, Illinois , on September 3, 1908. He graduated from Washington University School of Dental Medicine in their first class. [ 3 ] He then established his private practice in Edwardsville, Illinois . In 1941, he established an orthodontic practice with Leo B. Lundugan from 1938 to 1941. He then was enlisted into army in 1941, where he was a captain and then a major and a colonel. During World War II in 1942, he was director of the dental services in the 40th Station Hospital in Mostaganem , Algeria. After he served three years in the war, he was award the Bronze Star and an Army Commendation. He then returned to teaching at Washington University in the Department of Orthodontics for next 60 years. He became a professor and then the chairman of orthodontic department from 1953 to 1975. He co-wrote a textbook with James E. McCoy called Applied Orthodontics . He also wrote a book on his hometown called Marine, Illinois – An Historical Review.
He died on May 18, 1991, due to a cerebral hemorrhage . He was married to Wilma A. Shwartz.
This dentistry article is a stub . You can help Wikipedia by expanding it .
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Earl Howard Wood (January 1, 1912 – March 18, 2009) was an American cardiopulmonary physiologist who helped invent the G-suit , brought heart catheterization into a clinical reality and introduced dynamic volumetric computed tomography for the study of the heart and lungs. [ 2 ] [ 3 ] [ 4 ] [ 5 ]
Shortly after receiving an M.D. and PhD in physiology from the University of Minnesota medical school under the mentorship of Professor Maurice B. Visscher , MD, [ 6 ] Wood became a key member of a team, working in a laboratory at the Mayo Clinic , tasked with helping military pilots and flight crew survive and function in high G-force environments. Based upon extensive physiologic testing via use of the human centrifuge installed at the Mayo Clinic, it was determined that blackout and then unconsciousness was caused by reduction of blood flow to the eyes first and then the brain. [ 7 ] The solutions the team arrived at were the M-1 breath hold maneuver [ 8 ] [ 9 ] and the G-suit . [ 10 ] [ 11 ] The M-1 maneuver consisted of a strained exhalation effort against a closed glottis designed to increase left ventricular pressure. (Although the references given are dated 1946-7, the work was performed much before then. In, [ 7 ] see the acknowledgments section [ 7 ] : 342 explaining the closed nature of the research with restrictions placed on publication during the war. During the war effort the Mayo Clinic laboratory was operating with government Confidential secrecy.) The G suit was a garment, produced by the David Clark Company , which has air bladders situated at the calves, thighs, and abdomen of the wearer. The bladders inflate as the G-force acting on the aircraft increase, constricting the wearer's arteries, hence increasing blood pressure and blood flow to the brain.
The G-suit was a superior solution to another alternative (a water-filled suit) being tested at the time, which was considered impractically heavy and cumbersome. The water-filled, pulsatile pressure suits were developed to effect venous return. However, Wood and colleagues' detailed physiologic measurements demonstrated that what was required was augmentation of arterial pressure.
Wood himself regularly tested the flight suits, taking many turns in a human centrifuge and plane dubbed the "G-wiz". He calculated that during more than a thousand rides, he had lost consciousness for an aggregate of at least fifteen minutes (without any observed lasting damage). Wood was awarded a Presidential Certificate of Merit by Harry Truman in 1947.
The G-suit was adopted in the 1940s. The current models are based on the pattern Wood and his colleagues designed. Following World War II, Wood was recruited to participate in what was known as " Operation Paperclip " [ 12 ] The goal was to keep the top German scientists away from Russia and working for the United States.
In 1962, Wood was the tenth scientist to be named "Career Investigator," of the American Heart Association. [ 13 ] These funds allowed Wood considerable flexibility in regards to the directions of his research.
After his work on the G-Suit, Wood worked on techniques for measuring cardiac blood flow. He was granted a patent for the ear oximeter, an optical instrument that measures blood oxygen levels without taking blood by examining the variation of light absorption as a function of oxygen saturation of hemoglobin. Integral to the work leading to the development of the G suit was the perfection of vascular catheterization methods needed to understand the distribution of blood pressure and flow. Shortly after the end of World War II, open-heart surgery emerged with the Mayo contribution [ 14 ] to the development of the heart-lung bypass machine initially developed by Gibbons [ 15 ] and perfected by Wood and colleagues. [ 14 ] [ 16 ] Wood's work at the Mayo Clinic lead to the development of many technologies [ 5 ] allowing for the assessment of the heart and lungs including dye dilution methods serving to characterize cardiac output, [ 17 ] methods for the assessment of central blood volume, [ 18 ] the calculation of pulmonary vascular resistance (known as the "Wood Unit" and calculated by subtracting pulmonary capillary wedge pressure from the mean pulmonary arterial pressure and dividing by the cardiac output), [ 19 ] [ 20 ] [ 21 ] analog subtraction angiography, and eventually the Dynamic Spatial Reconstructor (DSR), a predecessor to modern high speed volumetric computed tomography (CT) allowing for the evaluation of the beating heart and breathing lungs. The DSR comprised 14 X-ray tubes and a hemicylindrical fluorescent screen imaged by 14 associated television cameras. [ 22 ] [ 23 ]
In all, Wood is noted for his contributions (together with members of the Biodynamics Research Unit (BRU), under his direction, within the physiology and biophysics department at the Mayo Clinic ) in the following areas:
Wood's publication list, with more than 700 entries, is a testament to the number of fellows who trained under him and who became prominent researchers in their own right.
Earl Wood was born to Inez Goff and William Clark Wood in Mankato, Minnesota on January 1, 1912 and started life on a subsistence farm. [ 4 ] William Wood, in addition to farming, was a real estate businessman. Earl Wood earned a B.A. in Mathematics and Chemistry from Macalester College in 1934, and his MD degree and a PhD degree in physiology from the University of Minnesota. Earl was one of 5 brothers (Earl, Chester, Delbert, Harland and Abe) and a sister, Louise.
All of Earl Wood's siblings grew up to be highly accomplished. [ 13 ] Louise A. Wood was awarded the Medal of Freedom by President Truman for her services as overseas director of the American Red Cross during World War II. and became the executive director of the Girl Scouts of the USA from 1961 to 1972. Harland G. Wood was the first director of the department of biochemistry at the school of medicine and dean of sciences, Case Western Reserve University. As a biochemist, he was notable for proving in 1935 that animals, humans and bacteria utilized carbon dioxide [ 54 ] and received the National Medal of Science. Chester was a teacher and a university administrator; Delbert was, in succession, a lawyer, a Federal Bureau of Investigation agent, and a railway executive; Abe was an internist and founder of a Colorado-based medical clinic. Not surprisingly, in 1950, Earl Wood's mother, Inez, was awarded the title of "Minnesota Mother of the Year." [ 13 ] Earl and his wife, Ada, had a daughter, Phoebe and three sons, Mark, Guy and E. Andrew.
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Early intervention in psychosis is a clinical approach to those experiencing symptoms of psychosis for the first time. It forms part of a new prevention paradigm for psychiatry [ 1 ] [ 2 ] and is leading to reform of mental health services , [ 3 ] especially in the United Kingdom [ 4 ] [ 5 ] and Australia.
This approach centers on the early detection and treatment of early symptoms of psychosis during the formative years of the psychotic condition. The first three to five years are believed by some to be a critical period. [ 6 ] The aim is to reduce the usual delays to treatment for those in their first episode of psychosis. The provision of optimal treatments in these early years is thought to prevent relapses and reduce the long-term impact of the condition. It is considered a secondary prevention strategy.
The duration of untreated psychosis (DUP) has been shown as an indicator of prognosis , with a longer DUP associated with more long-term disability. [ 7 ]
There are a number of functional components of the early psychosis model, [ 8 ] [ 9 ] [ 10 ] and they can be structured as different sub-teams within early psychosis services. The emerging pattern of sub-teams are currently:
Multidisciplinary clinical teams providing an intensive case management approach for the first three to five years. The approach is similar to assertive community treatment , but with an increased focus on the engagement and treatment of this previously untreated population and the provision of evidence based, optimal interventions for clients in their first episode of psychosis. For example, the use of low-dose antipsychotic medication is promoted ("start low, go slow"), with a need for monitoring of side effects and an intensive and deliberate period of psycho-education for patients and families that are new to the mental health system. In addition, research showed that family intervention for psychosis (FIp) reduced relapse rates, hospitalization duration, and psychotic symptoms along with increasing functionality in first-episode psychosis (FEP) up to 24 months. [ 11 ] Interventions to prevent a further episodes of psychosis (a "relapse") and strategies that encourage a return to normal vocation and social activity are a priority. There is a concept of phase specific treatment for acute, early recovery and late recovery periods in the first episode of psychosis. [ 12 ]
Interventions aimed at avoiding late detection and engagement of those in the course of their psychotic conditions. [ 13 ] Key tasks include being aware of early signs of psychosis and improving pathways into treatment. [ 14 ] Teams provide information and education to the general public and assist GPs with recognition and response to those with suspected signs, for example: EPPIC's [ 15 ] Youth Access Team (YAT) [ 16 ] ( Melbourne ); OPUS [ 17 ] ( Denmark ); TIPS [ 18 ] ( Norway ); REDIRECT [ 19 ] ( Birmingham ); LEO CAT ( London ) [ 20 ] "; STEP's Population Health approach to early detection. [ 21 ] [ 22 ]
The development and implementation of quantitative tools for early detection of at-risk individuals is an active research area. This includes development of risk calculators [ 23 ] and methods for large-scale population screening. [ 24 ]
Prodrome or at risk mental state clinics are specialist services for those with subclinical symptoms of psychosis or other indicators of risk of transition to psychosis. The Pace Clinic [ 25 ] in Melbourne, Australia, is considered one of the origins of this strategy, [ 26 ] but a number of other services and research centers have since developed. [ 27 ] [ 28 ] These services are able to reliably identify those at high risk of developing psychosis [ 29 ] and are beginning to publish encouraging outcomes from randomised controlled trials that reduce the chances of becoming psychotic, [ 30 ] including evidence that psychological therapy [ 31 ] and high doses of fish oil [ 32 ] have a role in the prevention of psychosis. However, a meta-analysis of five trials found that while these interventions reduced risk of psychosis after 1 year (11% conversion to psychosis in intervention groups compared to 32% in control groups), these gains were not maintained over 2–3 years of follow-up. [ 33 ] These findings indicate that interventions delay psychosis, but do not reduce the long-term risk. There has also been debate about the ethics of using antipsychotic medication to reduce the risk of developing psychosis, because of the potential harms involved with these medications. [ 34 ]
In 2015, the European Psychiatric Association issued guidance recommending the use of the Cognitive Disturbances scale (COGDIS), a subscale of the basic symptoms scale , to assess psychosis risk; a meta-analysis conducted for the guidance found that while rates of conversion to psychosis were similar to those who meet Ultra High Risk (UHR) criteria up to 2 years after assessment, they were significantly higher after 2 years for those patients who met the COGDIS criteria. [ 35 ] The COGDIS criteria measure subjective symptoms, and include such symptoms as thought interference , where irrelevant and emotionally unimportant thought contents interfere with the main line of thinking; thought block , where the current train of thought halts; thought pressure , where thoughts unrelated to a common topic appear uncontrollably; referential ideation that is immediately corrected; and other characteristic disturbances of attention and the use or understanding of language.
Early intervention in psychosis is a preventive approach for psychosis that has evolved as contemporary recovery views of psychosis and schizophrenia have gained acceptance. It subscribes to a "post Kraepelin" concept of schizophrenia, challenging the assumptions originally promoted by Emil Kraepelin in the 19th century, that schizophrenia (" dementia praecox ") was a condition with a progressing and deteriorating course. The work of Post, whose kindling model, together with Fava and Kellner, who first adapted staging models to mental health, provided an intellectual foundation. Psychosis is now formulated within a diathesis–stress model , allowing a more hopeful view of prognosis, and expects full recovery for those with early emerging psychotic symptoms. It is more aligned with psychosis as continuum (such as with the concept of schizotypy ) with multiple contributing factors, rather than schizophrenia as simply a neurobiological disease .
Within this changing view of psychosis and schizophrenia, the model has developed from a divergence of several different ideas, and from a number of sites, beginning with the closure of psychiatric institutions signaling a move toward community based care. [ 36 ] In 1986, the Northwick Park study [ 37 ] discovered an association between delays to treatment and disability, questioning the service provision for those with their first episode of schizophrenia. In the 1990s, evidence began to emerge that cognitive behavioural therapy was an effective treatment for delusions and hallucinations . [ 38 ] [ 39 ] [ 40 ] The next step came with the development of the EPPIC early detection service in Melbourne , Australia in 1996 [ 15 ] and the prodrome clinic led by Alison Yung. This service was an inspiration to other services, such as the West Midlands IRIS group, including the carer charity Rethink Mental Illness ; the TIPS early detection randomised control trial in Norway ; [ 18 ] and the Danish OPUS trial . [ 17 ] In 2001, the United Kingdom Department of Health called the development of early psychosis teams "a priority". [ 41 ] The International Early Psychosis Association , founded in 1998, issued an international consensus declaration together with the World Health Organization in 2004. [ 42 ] [ 43 ] Clinical practice guidelines have been written by consensus. [ 9 ]
There is evidence that providing access to specialized early intervention services results in benefits to patients during treatment. Such services lead to higher satisfaction among patients, and patients who have access to specialized early intervention services are more likely to stay in treatment, according to a 2020 Cochrane review . The same review also found that early intervention improved long-term global functioning outcomes; however, the evidence for this conclusion was of a lower quality, and all studies included in the review had been conducted in high-income countries, so it is not clear how these result will translate to lower-income countries. It is also unclear whether the benefits derived from early intervention persist once the patient is transferred to non-specialized treatment. [ 44 ]
One argument in favor of creating early intervention services is that they not only improve clinical outcomes for individual patients, but also cost less than standard services to operate, for example by reducing in-patient costs. [ 45 ] [ 46 ] A systematic review conducted in 2019 concluded that there is evidence to support this claim; however, many of the available studies on the cost-effectiveness of these services have methodological flaws, and it is unclear whether their results will translate to lower-income countries. [ 47 ] Another review conducted in 2020 likewise found low-certainty evidence that early intervention reduces the risk of subsequent in-patient hospitalization. [ 44 ]
The United Kingdom has made significant service reform with their adoption of early psychosis teams following the first service in Birmingham set up by Professor Max Birchwood in 1994 and used as a blueprint for national roll-out, with early psychosis now considered as an integral part of comprehensive community mental health services. The Mental Health Policy Implementation Guide outlines service specifications and forms the basis of a newly developed fidelity tool. [ 41 ] [ 48 ] There is a requirement for services to reduce the duration of untreated psychosis, as this has been shown to be associated with better long-term outcomes. The implementation guideline recommends:
In Australia the EPPIC initiative provides early intervention services. [ 49 ] In the Australian government's 2011 budget, $222.4 million was provided to fund 12 new EPPIC centres in collaboration with the states and territories. [ 50 ] However, there have been criticisms of the evidence base for this expansion and of the claimed cost savings. [ 51 ] [ 52 ] [ 53 ]
On August 19, 2011, Patrick McGorry , South Australian Social Inclusion Commissioner David Cappo AO and Frank Quinlan, CEO of the Mental Health Council of Australia, addressed a meeting of the Council of Australian Governments (COAG), chaired by Prime Minister Julia Gillard , on the future direction of mental health policy and the need for priority funding for early intervention. [ 54 ] The invitation, an initiative of South Australian Premier Mike Rann , followed the release of Cappo's "Stepping Up" report, supported by the Rann Government, which recommended a major overhaul of mental health in South Australia, including stepped levels of care and early intervention. [ 55 ]
New Zealand has operated significant early psychosis teams for more than 20 years, following the inclusion of early psychosis in a mental health policy document in 1997. [ 56 ] There is a national early psychosis professional group, New Zealand Early Intervention for Psychosis Society (NZEIPS), [ 57 ] organising a biannual training event, advocating for evidenced based service reform and supporting production of local resources.
Early psychosis programmes have continued to develop from the original TIPS services in Norway . [ 18 ] [ needs update ]
In Denmark , an early intervention programme called OPUS was introduced as a randomized trial between 1998 and 2000. [ 17 ] The trial was considered successful and OPUS was subsequently made the standard treatment programme for people aged 18–35. Later analysis of the effects of the programme conducted in 2021 showed that it had not only maintained its effects from the first trial, but that it had in fact been even more effective following its nationwide adoption as the standard treatment. [ 58 ] [ 59 ]
Canada has extensive coverage across most provinces, including established clinical services and comprehensive academic research in British Columbia ( Vancouver ), Alberta (EPT in Calgary ), Quebec (PEPP-Montreal), and Ontario (PEPP, FEPP).
In the United States, the Early Assessment Support Alliance (EASA) is implementing early psychosis intervention throughout the state of Oregon. [ 60 ]
In the United States, the implementation of coordinated specialty care (CSC), as a recovery-oriented treatment program for people with first episode psychosis (FEP), has become a US health policy priority. [ 61 ] CSC promotes shared decision making and uses a team of specialists who work with the client to create a personal treatment plan. The specialists offer psychotherapy, medication management geared to individuals with FEP, family education and support, case management, and work or education support, depending on the individual's needs and preferences. The client and the team work together to make treatment decisions, involving family members as much as possible. The goal is to link the individual with a CSC team as soon as possible after psychotic symptoms begin [ 62 ] because a longer period of unchecked and untreated illness might be associated with poorer outcomes. [ 63 ] [ 64 ] [ 65 ] [ 66 ]
The first meeting of the Asian Network of Early Psychosis (ANEP) was held in 2004. There are now established services in Singapore , [ 67 ] Hong Kong [ 68 ] and South Korea [ 69 ]
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Early pregnancy loss is a medical term that when referring to humans can variously be used to mean:
Pregnancy loss, in many cases, occurs for unknown reasons, often involving random chromosome issues during conception. Miscarriage is not caused by everyday activities like working, exercising, or having sex. Even falls or blows are rarely to blame. Research on the effects of alcohol, tobacco, and caffeine on miscarriage is inconclusive, so it's not something you could have prevented. It's crucial not to blame yourself for a miscarriage, as it's not the result of anything you did or didn't do. [ 2 ]
The most prevalent indication of pregnancy loss is vaginal bleeding. In the later stages of pregnancy, a woman experiencing a stillbirth may cease to sense fetal movements. However, it's important to note that each type of pregnancy loss presents distinct symptoms, so it's essential to consult your healthcare provider for a proper diagnosis. [ 3 ]
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Early prostate cancer antigen-2 ( EPCA-2 ) is a protein of which blood levels are elevated in prostate cancer . It appears to provide more accuracy in identifying early prostate cancer than the standard prostate cancer marker, PSA .
"EPCA-2" is not the name of a gene. EPCA-2 gets its name because it is the second prostate cancer marker identified by the research team. This earlier marker was previously known as "EPCA", [ 1 ] [ 2 ] but is now called "EPCA-1".
Leman, Getzenberg and colleagues describe, in the April 2007 issue of Urology, the performance characteristic of EPCA-2, a novel nuclear protein marker for prostate cancer cells. This paper has since been retracted by the publisher. [ 3 ] [ 4 ]
A study was initiated which suggested that the EPCA-2 protein serum assay exhibits favorable performance characteristics which are potentially superior to serum PSA. However more studies are necessary to see if this test will retain its sensitivity when used in a screening population. [ citation needed ]
In September 2008 the industry sponsor of EPCA-2, Onconome sued Dr Robert Getzenberg, JHU, and the University of Pittsburgh, his previous institution, claiming that Getzenberg misrepresented and falsified data related to EPCA-2 after Onconome sponsored 13 million dollars of research over five years in Getzenberg's labs at University of Pittsburgh and Johns Hopkins for a blood test for prostate cancer. Onconome claimed that the test was "essentially as reliable as flipping a coin". Robert H. Getzenberg (Ph.D-JHU 1992), first developed EPCA-2 as a graduate student with Professor Donald Coffey at Johns Hopkins and later as a faculty member at University of Pittsburgh. Getzenberg, former professor of Urology and Director of Research of the James Buchanan Brady Urological Institute, left Johns Hopkins University School of Medicine in 2013 for undisclosed reasons. [ 5 ] [ 6 ]
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The Early versus Late Intervention Trial with Estradiol ( ELITE ) was a large randomized controlled trial that assessed the timing hypothesis that menopausal hormone therapy in early but not late menopause would improve cardiovascular outcomes. [ 1 ] [ 2 ]
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An earmold (also spelled; ear mold , ear mould or earmould ) is a device worn inserted into the ear for sound conduction or hearing protection . Earmolds are anatomically shaped and can be produced in different sizes for general use or specially cast from particular ear forms. [ 1 ] Some users specify how hard or soft they want their mold to be, an audiologist can also suggest this. As a conductor, it improves sound transmission to eardrums . This is an essential feature to diminish feedback paths in hearing aids and assure better intelligibility in noisy-environment communication. The main goal in wearing earmolds is to attain better user comfort and efficiency. Earmolds (and their tubes) often turn yellow and stiff with age, and thus need replacement on a regular basis. [ 2 ] Traditionally, the job of making earmolds is very time-consuming and skillful; each one is made individually in a molding process. However, new digital ear laser scanners can accelerate this process. [ 3 ]
The texture of the earmold can have low, medium, or high viscosity . The lower type of viscosity will be soft while the higher viscosity is firm. It is thought that a higher viscosity will lead to a better impression of the ear canal while the lower viscosity may not fill in the ear canal as well. The type of viscosity to use is dependent on the person using the material and the type of viscosity they are most comfortable with. [ 4 ]
Once the viscosity is chosen the person can then choose to use a pistol or syringe for pushing the ear impression material in the ear. The syringes need the material mixed together until it is a singular color and then it can be pushed through the tube of the syringe. The plunger of the syringe will then be used to push the material into the smaller area. [ 5 ] The pistol uses pre-measured impression material and requires the person to press the trigger lever for the impression material to come out. Before the impression material is set in the external auditory canal, otoscopy needs to be performed to make sure the canal is free of cerumen or any other foreign objects. With the impression material ready to use the clinician will want to put an otoblocker into the ear canal. This will help prevent material from reaching the tympanic membrane of the middle ear . For the otoblocker to be put in appropriately the clinician will want to pull up on the top of the pinna so the otoblocker can be put past the second bend of the ear canal. [ 6 ] With the otoblocker in place the impression material can now be used to fill in the external ear canal and the spaces and crevices of the outer ear. [ 4 ]
With the impression material in place and set in the ear canal the clinician can decide what type of earmold material would benefit the patient the most. The three types of earmold materials include: acrylic, polyvinyl chloride, and silicone. Each type of material has positives and negatives about them, for instance, acrylic can help older patients with dexterity issues as the earmold is hard so insertion and removal of the earmold is easier or a silicone earmold which is soft and is extremely useful for children because of how pliable the material is. [ 4 ]
Earmolds present a variety of challenges. They can be inconsistent, time-consuming, or inaccurate. [ 7 ] [ 8 ] This is why, in the early 2000s, [ 7 ] a new idea for determining the anatomical shape of the individual's ear canal began circulating. The Navy often had issues with earmolds, for the fact that once the initial impression was taken, the impressions would have to be shipped to a manufacturer before the hearing protection could be made. [ 7 ] This made imperative personal protective equipment often time-consuming and difficult to obtain. [ 7 ] This is why the Navy then began looking for universities to create an anatomical 3D model of the ear using a scanner. The idea was that these scans could be sent electronically to manufacturers almost instantaneously. [ 7 ] Karol Hatzilias from Georgia Tech undertook inventing an ear scanner, which has since then been successfully integrated onto Naval ships. [ 7 ] This technology has slowly been working its way into clinical settings. Many different companies have come up with their own version of ear scanning.
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An earplug is a device that is inserted in the ear canal to protect the user's ears from loud noises, intrusion of water, foreign bodies, dust or excessive wind . Earplugs may be used as well to improve sleep quality or focus in noisy environments. Since they reduce the sound volume, earplugs may prevent hearing loss and tinnitus (ringing of the ears), in some cases. [ 1 ] [ 2 ]
US Occupational Safety and Health Administration requires hearing conservation programs which include the provision of hearing protection devices (HPDs). But this does not mean that OSHA considers HPDs to be effective. [ 3 ]
The first recorded mention of the use of earplugs is in the Greek tale Odyssey , wherein Odysseus 's crew is warned about the Sirens that sing from an island they will sail past. Circe , their hostess, tells them of the Sirens' bewitching song that makes men drive their boats ashore and perish. She advised Odysseus to fashion earplugs for his men from beeswax so they would not be lured to their deaths by the sirens' song.
In 1907, the German company Ohropax, which would produce mainly wax earplugs, was started by the German inventor Max Negwer. Ray and Cecilia Benner invented the first moldable pure silicone ear plug in 1962. These earplugs were valued by swimmers because of their waterproof qualities, as well as those trying to avoid harmful noise. Ray Benner, who was a Classical musician, bought McKeon Products in 1962. At that time, the company's sole product was Mack's Earplugs (named after the original owner), which was a moldable clay earplug. The Benners quickly redesigned the product to a silicone version, which would become known as Mack's Pillow Soft Earplugs. [ citation needed ]
Present-day earplug material was discovered in 1967, at National Research Corporation (NRC) in the US by Ross Gardner Jr. and his team. As part of a project on sealing joints, they developed a resin with energy absorption properties. They came to call this material "E-A-R" (Energy Absorption Resin). In 1972 the material was refined into commercial memory foam earplugs, made from either polyvinyl chloride or polyurethane. [ citation needed ]
There are mainly four types of earplug fittings for hearing protection:
NIOSH Mining Safety and Health Research recommends using the roll, pull, and hold method when using memory foam earplugs. [ 4 ] The process involves the user rolling the earplug into a thin rod, pulling back on the ear, and holding the earplug deep in the ear canal with the finger. [ 4 ] To get a complete seal, the user must wait about 20 to 30 seconds for the earplug to expand inside the canal. [ 5 ]
Earplugs are most effective when the wearer has been properly trained on use and insertion. Employers can provide this training before dispensing earplugs to their employees. Training for earplug use includes: insertion, a seal check, depth check, removal, cleaning, and replacement. When training on insertion, the objective is for the worker to understand the correct insertion strategy. Proper insertion training prevents inadequate insertion, that can result in discomfort or inadequate attenuation, which can result in hearing loss. When this step is achieved, then the seal and depth need to be checked. The ear plugs all have a desired depth and seal which need to be achieved to provide the designated attenuation for the wearer. The worker will also be trained on how to properly remove the earplugs and clean them. This allows for multiple uses and reduces the chance of infection. To further prevent infection, it is important the worker understands when they will need to replace their earplugs. Once the plugs have been worn down from repeated use, they will no longer seal correctly or provide the proper attenuation level, and the device will need to be replaced. [ 6 ]
Noise attenuation can be verified using real-ear attenuation at threshold (REAT) or microphone in the real ear (MIRE) methods. [ 7 ] The difference in thresholds with and without the hearing protection in place determines the amount of attenuation (REAT). [ 8 ] Two microphones measure the sound pressure (of test signals, or noise in the workplace during a shift) outside the HPD and inside, and the difference shows the noise attenuation (MIRE).
Earplugs and other hearing protection devices can be tested to ensure that they fit properly and are successfully limiting sound exposure, which is called fit-testing . There are a number of different fit-testing systems, also known as field attenuation estimation systems (FAES). These use large headphones or specialized (surrogate) earplugs to transmit the test sounds and measure the attenuation provided by the hearing protector. These systems include the NIOSH HPD Well-Fit, Honeywell Howard Leight VeriPRO, 3MEARFit and many others. [ 7 ]
TWA 90 dB(A),
exchange rate 5 dB
TWA 85 dB(A),
exchange rate 3 dB
TWA 80 dB(A),
exchange rate 3 dB
(for an 8-hour shift)
(Exchange rate)
These numerical values do not fully reflect the real situation. For example, the OSHA standard [ 9 ] sets the Action Level 85 dBA, and the PEL 90 dBA. But in practice, the Compliance Safety and Health Officer must record the excess of these values with a margin, in order to take into account the potential measurement error. And, in fact, instead of PEL 90 dBA, it turns out 92 dBA, and instead of AL 85 dBA - 87 dBA. [ 19 ]
The diameter of the ear canals can be from 3 to 14 mm. They can be round, elliptical, and even slit-like. The ear canals may be straight, but more often curved to varying degrees. The shape and size of the right and left ear canals for the same worker can vary significantly. [ 20 ] Installing the earplugs neatly and tightly (without gaps) can be a difficult task.
Since the fitting of the earplugs greatly affects their noise attenuation, [ 7 ] various designs of these personal protective equipment have been developed.
Basic foam style earplug protection is often worn by industrial workers who work within hearing distance of loud machinery for long periods of time, and is used by the British Ministry of Defence (MoD) for soldiers to use when firing weapons. Earplugs are rated for their ability to reduce noise; see § Rating .
Most disposable earplugs are elastic ones made of memory foam , that is typically rolled into a tightly compressed cylinder (without creases) by the user's fingers and then inserted in the ear canal. Once released, the earplug expands until it seals the canal, blocking the sound vibrations that could reach the eardrum . Other disposable plugs simply push into the ear canal without being rolled first. Sometimes earplugs are connected with a cord to keep them together when not in use. Other common material bases for disposable earplugs are viscous wax or silicone .
Other devices that provide hearing protection include electronic devices worn around and/or in the ear, and are designed to cancel out the loud noise of a gunshot, while possibly amplifying quieter sounds to normal levels. While rich in features, these electronic devices are more expensive, compared to their foam counterparts.
In other activities, hobby motorcyclists and skiers may also choose to use decibel reduction earplugs, to compensate for the ongoing noise of the wind against their head or helmet.
Musicians are exposed to potentially harmful levels of sound, which can lead to hearing loss , tinnitus, and other auditory symptoms. Because of this, musicians may choose to use earplugs.
Musician's earplugs (also called Hi-Fi or Lossless earplugs [ citation needed ] ) are designed to attenuate sounds evenly across all frequencies (pitches) which helps maintain the ear's natural frequency response and thus minimizes the effect on the user's perception of timbre (frequency spectrum, f.ex. bass and treble levels). These are commonly used by musicians and technicians, both in the studio and in concert, to avoid overexposure to high volume levels. Musician's earplugs generally achieve a more natural frequency response by incorporating a small diaphragm or membrane together with acoustic channels and damping materials. [ 21 ] Simpler variants with only a small hole introduce a low frequency leak, and will not achieve a flat frequency response. Examples of manufacturers of membrane-based earplugs are ACS, Etymotic and Minuendo .
Preformed earplugs, such as the ER-20 earplug are universal (non-custom) earplugs with a noise reduction rating (NRR) of about 12 dB. A selection of musician's earplugs have been reviewed by the National Acoustic Laboratories and The HEARing CRC in conjunction with Choice . [ 22 ] [ 23 ] The review results (which include attenuation measures and user ratings of comfort, fit and sound quality) are available at What Plug?. [ 24 ]
A more expensive option is the custom molded musician's earplug, which is custom-made for the individual listener. These earplugs are typically made out of silicone or vinyl materials and come with a vent and a variety of filters that can change the amount of attenuation provided. Common static filter attenuation levels are 9, 15, and 25 dB. [ 25 ] This type of plug is quite popular among audio engineers who can safely listen to loud mixes for extended periods of time. However, they can be quite costly, being intended for constant re-use unlike simple earplugs which are disposable.
Alternately, musicians may use in-ear monitors , which are essentially headphones that also serve as earplugs by attenuating surrounding sound. In order for in-ear monitors to double up as hearing protection, custom earpieces should be used. The process for having custom earpieces made is similar to that of the custom musician's earplug and, similarly, the earpiece will be made of silicone or vinyl. While using an in-ear monitor can help protect hearing, the amount of protection provided by the monitor depends on the listening level that the musician chooses. Because of this, if the musician sets the monitor to a high level, the monitor may attenuate surrounding sound while still providing a potentially harmful level of sound directly to the musician's ear and therefore no longer serve a protective function. [ 25 ]
Several earplugs on the market claim to be for musicians, but are not in fact by definition a musician's earplug. By having a thin acoustical bypass channel, they allow for a slightly better frequency response and lower attenuation than simple earplugs, but far from the level of fidelity that membrane-based earplugs provide. These types of earplugs do not provide the flat attenuation that is characteristic of a musician's plug, but may still be useful for some, due to their lower price points. [ 25 ]
Earplugs can be molded to fit an individual's ear canal. This costs more, but can improve fit for the few percent that have an ear anatomy outside the norm. [ 26 ]
Custom molded earplugs fall into two categories: Laboratory made and Formed in Place. Laboratory made requires an impression to be made by a professional of the ear canal and outer ear. The impression is sent to a laboratory to be checked and made into a hearing protector. Formed in place uses the same process to make an impression of the ear canal and outer ear and then turns that impression into the protector. Both types of custom molded earplugs are non-disposable with the laboratory made typically lasting for 3 – 5 years and the formed in place lasting for 1 – 2 years.
For the best attenuation and proper fit, the impressions for custom molds must meet a desired criteria by the manufacturer of the mold. Before an impression can be taken for the custom mold the ear canal is checked for any wax or physical abnormalities. This is important in making sure there is a proper seal with the impression material and also not to push any wax deep into the canal. The otoblock (made with foam or cotton) will be inserted deep in the canal to prevent the impression material from going too far. The impression material (either silicone or powder/liquid) will be placed into the ear canal. This will need to be fully made, making sure there are no gaps or creases in the impression. If there are, then the mold made from the impression will not adequately seal the ear canal. Once the custom mold is made, it will need to be inspected by the Audiologist for proper fit on the patient. Hearing protection should also be verified using real-ear methods to ensure proper attenuation. Real-ear attentuation at threshold (REAT) measurements test how narrowband noises of varying frequency are attenuated with and without the custom mold in place. Testing for low-frequency attenuation can help to verify the earmold fit while testing high-frequency attenuation can verify the properties of the filter used. [ 6 ] [ 21 ]
For best results they are molded in the ear while in the position that they will be used. For instance, if they are to be used for sleeping then they should be molded in the ear while lying down, as different positioning of the jaws causes significant changes to the form of the ear canal, mostly a reduction of the diameter, risking the sleep earplug to be made too large otherwise. It is also important that during the impression process that a music performer use their embouchure or move the jaw to mimic singing in order to account for ear canal changes during performance. Therefore, if the impression is not properly constructed, then it will need to be redone. [ 21 ] These changes can be felt by feeling with a finger just at the entrance to the ear canal while moving the jaws sideways, up and down or anterior and posterior .
Most molded earplugs are made from silicone but other materials may be used, including thermoplastics, [ 27 ] plastic, nylon [ 28 ] and even 3-D printed earplugs.
The noise reduction of passive earplugs varies with frequency but is largely independent of level (soft noises are reduced as much as loud noises). As a result, while loud noises are reduced in level, protecting hearing, it can be difficult to hear low level noises. Active electronic earplugs exist, where loud noises are reduced more than soft noises, and soft sounds may even be amplified, providing dynamic range compression . This is done by having a standard passive earplug, together with a microphone/speaker pair (microphone on outside, speaker on inside; formally a pair of transducers ), so sound can be transmitted without being attenuated by the earplug. When external sounds exceed an established threshold (typically 82 dBA SPL), the amplification of the electronic circuit is reduced. At very high levels, the amplification is turned off automatically and you receive the full attenuation of the earplug just as if it were turned off and seated in the ear canal. This protects hearing, but allows one to hear normally when sounds are in safe ranges – for example, have a normal conversation in a low-noise situation, but be protected from sudden loud noises, for example at a construction site or a while hunting.
Nonlinear earplugs provide similar advantages to electronic earplugs but do not require electricity. They are designed with a thin diaphragm which allows the amount of noise reduction to increase in proportion to the sound level to which the wearer is exposed. [ 29 ] This makes them useful for applications where situational awareness is required but noise protection is also necessary, such as the military or police.
Earplugs for sleeping are made to be as comfortable as possible while blocking external sounds that may prevent or disrupt sleep. Specialized earplugs for such noises as a partner's snoring may have sound-dampening enhancements that enable the user to still hear other noises, such as an alarm clock. [ 30 ]
To determine the comfort of earplugs used for sleeping, it is important to try them on while actually lying down. The pressure on the ear between the head and pillow may cause significant discomfort. Furthermore, just tilting the head back or to the side causes significant anatomical changes in the ear canal, mostly a reduction of the ear canal diameter, which may reduce comfort if the earplug is too large. Earplugs for sleeping may enhance recovery after major surgery. [ 31 ]
Some earplugs are primarily designed to keep water out of the ear canal, especially during swimming and water sports. This type of earplug may be made of wax or moldable silicone which is custom-fitted to the ear canal by the wearer.
Exostosis, or surfer's ear , is a condition which affects people who spend large amounts of time in water in cold climates. In addition, wind may increase the prevalence of the amount of exostosis seen in one ear versus the other dependent on the direction it originates from and the orientation of the individual to the wind. [ 32 ] Custom-fitted surfer's earplugs help reduce the amount of cold water and wind that is allowed to enter the external ear canal and, thus, help slow the progression of exostosis.
Another condition is otitis externa , which is an infection of the outer ear canal. This form of infection differs from those commonly occurring in children behind the eardrum, which is otitis media, or a middle ear infection. This infection's symptoms include: itchiness, redness, swelling, pain upon tugging of the pinna, or drainage. To protect from this form of infection, it is important to thoroughly dry the ears after exposing them to water with a towel. To protect the ears during exposure, the individual can use a head cap, ear plugs, or custom-fitted swim molds. [ 33 ]
A 2003 study published in Clinical Otolaryngology found that a cotton ball saturated with petroleum jelly was more effective at keeping water out of the ear, was easier to use, and was more comfortable than wax plugs, foam plugs, EarGuard, or Aquafit. [ 34 ]
Jacques-Yves Cousteau [ 35 ] warned that earplugs are harmful to divers, especially scuba divers . Scuba divers breathe compressed air or other gas mixtures at a pressure matching the water pressure. This pressure is also inside the ear, but not between the eardrum and the earplug, so the pressure behind the eardrum will often burst the eardrum. Skin divers have less pressure inside the ears, but they also have only atmospheric pressure in the outer ear canal. The PADI (Professional Association of Diving Instructors) advises in the "Open Water Diver Manual" that only vented earplugs designed for diving should be used in diving.
Earplugs are also available which help to protect ears from the pain caused by airplane cabin pressure changes. Some products contain a porous ceramic insert which reportedly aids equalization of air pressure between the middle and outer ear thereby preventing pain during landings and take-offs. Some airlines distribute regular foam earplugs as part of their amenity kits for passengers to aid their comfort during landings and takeoffs as well as to reduce exposure to the aircraft's noise during the flight. These can help passengers get to sleep during the flight if desired.
In the past, experts believed that HPDs noise attenuation in laboratories and workplaces were similar. Therefore, they developed different methods for predicting noise attenuation at the workplaces using lab data. Later, derating methods were developed. Many of these methods have been preserved in various regulatory documents and older standards.
Unfortunately, all these methods and derating do not take into account at all and are not able to take into account the strong individual variability in noise attenuation in principle, for example, plus or minus 20 decibels. [ 36 ] [ 2 ]
New standards have been developed that better correspond to the current level of science. [ 38 ] [ 39 ]
The United States Environmental Protection Agency (EPA) mandates that hearing protection is rated and labeled. To be rated, hearing protection is tested under ANSI S3.19-1974 to provide a range of attenuation values at each frequency that can then be used to calculate a Noise Reduction Rating (NRR). Under this standard a panel of ten subjects are tested three times each in a laboratory to determine the attenuation over a range of 9 frequencies.
In the European Union, hearing protectors are required to be tested according to the International Organization for Standardization (ISO) acoustical testing standard, ISO 4869 Part 1 and the Single Number Rating (SNR) or High/Middle/Low (HML) ratings are calculated according to ISO 4869 Part 2. In Brazil, hearing protectors are tested according to the American National Standards Institute ANSI S12.6-1997 and are rated using the Noise Reduction Rating Subject Fit NRR(SF). Australia and New Zealand have different standards for protector ratings yielding a quantity SLC80 (Sound Level Class for the 80th percentile). Canada implements a class system for rating the performance of protectors. Gauger and Berger have reviewed the merits of several different rating methods and developed a rating system that is the basis of a new American National Standard, ANSI S12.68-2007
The various methods have slightly different interpretations, but each method has a percentile associated with the rating. That percent of the users should be able to achieve the rated attenuation. For instance, the NRR is determined by the mean attenuation minus two standard deviations. Thus, it translates to a 98% statistic. That is, at least 98 percent of users should be able to achieve that level of attenuation. The SNR and HML are a mean minus one standard deviation statistic. Therefore, approximately 86% of the users should be able to achieve that level of protection. Similarly, the NRR (SF) is a mean minus one standard deviation and represents an 86% of users should achieve that level of protection. The difference between the ratings lies in how the protectors are tested. NRR is tested with an experimenter-fit protocol. SNR/HML are tested with an experienced subject-fit protocol. NRR (SF) is tested with a naive subject-fit protocol. According to Murphy, et al. (2004), these three protocols will yield different amounts of attenuation with the NRR being the greatest and NRR (SF) being the least.
The experimenter-fit NRR should be adjusted per the guidelines of the National Institute for Occupational Safety and Health as the required NRR ratings differ greatly from lab tests to field tests.
The NRR(SF) used in Brazil, Australia, and New Zealand does not require derating as it resembles the manner in which the typical user will wear hearing protection.
Hearing protectors sold in the US are required by the EPA to have a noise reduction rating (NRR), [ 40 ] which is an estimate of noise reduction at the ear when protectors are worn properly.
Real-ear attenuation at threshold (REAT) measurements are performed multiple times with 10 to 20 subjects to determine the NRR. Using the collected data, an average group attenuation is reported along with a standard deviation for attenuation on the hearing protector package. [ 8 ]
Due to the discrepancy between how protectors are fit in the testing laboratory and how users wear protectors in the real world, the Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH) have developed derating formulas to reduce the effective NRR.
While the NRR and the SNR (Single Number Rating) are designed to be used with C-weighted noise, which means that the lower frequencies are not de-emphasized, other ratings (NRR(SF) and NRSA) are determined for use with A-weighted noise levels, which have lower frequencies de-emphasized. NIOSH recommended and the U.S. EPA mandated [ 40 ] that 7-dB compensation between C and A weighting be applied when the NRR is used with A-weighted noise levels.
The OSHA training manual for inspectors says the adequacy of hearing protection for use in a hazardous noise environment should be derated to account for how workers typically wear protection relative to how manufacturers test the protector's attenuation in the laboratory. [ 41 ] For all types of hearing protection, OSHA's derating factor is 50%. If used with C-weighted noise, the derated NRR will become NRR/2. [ 41 ] If used with A-weighted noise, OSHA applies the 7-dB adjustment for C-A weighting first then derates the remainder. [ 41 ] For example, a protector with 33-dB attenuation would have this derating:
NIOSH has proposed a different method for derating based upon the type of protector. [ 42 ] For earmuffs , the NRR should be derated by 25%, for slow-recovery foam earplugs the derating is 50% for all other protection, the derating is 70%. NIOSH applies the C-A spectral compensation differently than OSHA. Where OSHA subtracts the 7-dB factor first and derates the result, NIOSH derates the NRR first and then compensates for the C-A difference. For example, to find the derated NRR for an earmuff by using the NIOSH derating system, the following equation would be used:
Painful discomfort occurs at approximately 120 to 125 dB(A), [ 43 ] with some references claiming 133 dB(A) for the threshold of pain. [ 44 ] Active ear muffs are available with electronic noise cancellation that can reduce direct path ear canal noise by approximately 17–33 dB, depending on the low, medium, or high frequency at which attenuation is measured. [ 45 ] Passive earplugs vary in their measured attenuation, ranging from 20 dB to 30 dB, depending on the fit of the earplugs, whether the employee can and knows how to insert the earplugs into the ear canal correctly, and whether they are used correctly [ 2 ] [ 46 ] and if low pass mechanical filters are also being used.
The Canadian standard requires the use of two passive protective measures simultaneously at noise levels above 105 dBA. But the noise reduction does not increase very much. It is recommended to estimate the attenuation by adding 5 dB to the highest attenuation of one of the two HPDs. This recommendation does not take into account individual differences at all, and may lead to error. [ 47 ]
Using both ear muffs (whether passive or active) and earplugs simultaneously results in maximum protection, but the efficacy of such combined protection relative to preventing permanent ear damage is inconclusive, with evidence indicating that a combined noise reduction ratio (NRR) of only 36 dB (C-weighted) is the maximum possible using ear muffs and earplugs simultaneously, equating to only a 36 - 7 = 29 dB(A) protection. [ 44 ] Some high-end, passive, custom-molded earplugs also have a mechanical filter inserted into the center of the earmolded plug, with a small opening facing to the outside; this design permits being able to hear range commands at a gun range, for example, while still having full rating impulse noise protection.
Such custom molded earplugs with low pass filter and mechanical valve typically have a +85 dB(A) mechanical clamp, in addition to having a lowpass filter response, thereby providing typically 30-31 dB attenuation to loud impulse noises, with only a 21 dB reduction under low noise conditions across the human voice audible frequency range (300–4000 Hz) (thereby providing low attenuation between shots being fired), to permit hearing range commands. Similar functions are also available in standardized earplugs that are not custom molded. [ 48 ] [ failed verification ]
The wide variation in recommendations [ 2 ] may be due in part to the very large inter-individual variability in results that cannot be predicted; but can be taken into account by individual measurements .
In 2007, the American National Standards Institute published a new standard for noise reduction ratings for hearing protectors, ANSI S12.68-2007. Using the real ear attenuation at threshold data collected by a laboratory test prescribed in ANSI S12.6-2008, the noise reduction statistic for A-weighted noise (NRSA) is computed using a set of 100 noises listed in the standard. [ 49 ] The noise reduction rating, rather than be computed for a single noise spectrum the NRSA incorporates variability of both subject and spectral effects. [ 49 ] ANSI S12.68 also defines a method to estimate the performance of a protector in an atypical noise environment.
Building upon work from the U.S. Air Force and the ISO 4869-2 standard, [ 50 ] the protector's attenuation as a function of the difference in C and A-weighted noise level is used to predict typical performance in that noise environment. The derating may be quite severe (10 to 15 decibels) for protectors that have significant differences between low and high frequency attenuation. For "flat" attenuation protectors, the effect of C-A is less. This new system eliminates the need for calculators, relies on graphs and databases of empirical data, and is believed to be a more accurate system for determining NRRs. [ 49 ]
Similar to a noise reduction rating (NRR) required on hearing protection devices in the United States, a personal attenuation rating (PAR) can be obtained through a hearing protection fit-testing system . [ 7 ] The PAR is subtracted from the measured noise exposure to estimate the total noise exposure an individual is receiving when wearing hearing protection. The PAR is regarded as more accurate than the NRR because it is calculated per individual and per hearing protection device, while NRR is a generalized estimate of potential sound reduction based on the protection provided to a small population of people. [ 52 ] [ 38 ]
In order to achieve significant attenuation, fit-testing and extensive personalized (one-on-one) training was found to be essential, whereas simple instructions did not lead to significant attenuation ove giving no instructions at all. [ 53 ]
Earplugs are generally safe, but some precautions may be needed against a number of possible health risks, with additional ones appearing with long-term use:
Custom shaped plugs are recommended for long-term use, since they are more comfortable and gentle to the skin and will not go too far into the ear canal.
Nevertheless, prolonged or frequently repeated use of earplugs has the following health risks, in addition to the short-term health risks:
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East Asian blepharoplasty , more commonly known as double eyelid surgery , is a cosmetic procedure that reshapes the skin around the eye to create a crease in an upper eyelid that naturally lacks one. Although 70-83% of East Asian women naturally have upper eyelid creases, it is estimated that 17-30% of Chinese and Japanese women lack this feature. [ 1 ] This surgery may be performed on ethnic East Asians , including people of Chinese , Japanese and Korean descent. The primary goal is to alter the eyelid's appearance, making the eyes appear larger and, to some tastes, more attractive due to a 'wide-eyed' and expressive appearance. [ 2 ]
The procedure was first performed in 1896 by Dr. Kotaro Mikamo in Japan, a period marked by significant Western influence following the Meiji Restoration . Mikamo's introduction of the surgery has been interpreted in different ways. Although the majority of Japanese women naturally have double eyelids, one perspective sometimes held by Westerners is that the procedure was intended to "westernize" the eyes of Japanese women, influenced by Western beauty standards that were purportedly becoming increasingly prevalent in Japan during the Meiji period. [ 3 ]
However, Mikamo recorded that the 82-83% of Japanese women actually have the double eyelid appearance, [ 1 ] making it a physiologically normative feature among the population. He described the single-eyelid look as being "monotonous and expressionless," suggesting that his motivation for the surgery was rooted in enhancing natural beauty rather than conforming to Western ideals. [ 4 ] According to this perspective, Mikamo was working within existing Japanese aesthetics and norms, aiming to accentuate a feature that was already prevalent and culturally appreciated in Japan. [ 5 ]
Asian blepharoplasty is primarily performed using two techniques: non-incisional and incisional methods.
The non-incisional method, or suture ligation, involves the strategic placement of sutures through all layers of the upper eyelid at the level of the upper tarsal margin. This technique facilitates adhesion between the subdermal tissues and the underlying levator aponeurosis , effectively creating the eyelid crease. It is less complex and has a shorter operation time, leading to a quicker recovery and fewer complications compared to more invasive methods. However, it tends to produce a static eyelid crease that does not vary with facial expressions and may diminish over time. Additionally, the underlying sutures can sometimes lead to corneal irritation.
The incisional method, known as surgical resection, entails making an incision across the upper eyelid to remove excessive tissue, including skin, subcutaneous fat , orbicularis oculi muscle , and other anatomical components. This approach not only allows for the creation of a more dynamic and permanent eyelid crease but also can address other aesthetic concerns by removing excess skin and fat. The results are more aligned with the natural anatomy of the eye, making the crease appear more natural and dynamic. However, this method is more complex, requiring a longer operation and recovery time. One significant risk is lagophthalmos, where excessive removal of lid tissue can prevent the eyelid from fully closing.
Each of these techniques offers distinct advantages and poses specific challenges, making the choice between them dependent on individual anatomical and aesthetic considerations.
Non-surgical methods for double eyelid formation involve the use of eyelid training tapes, adhesives, and crease reinforcement techniques . These approaches aim to create a fold in the upper eyelid without the need for invasive surgery.
East Asian blepharoplasty have been reported to be the most common aesthetic procedure in Taiwan , [ 6 ] South Korea and other parts of East Asia and is also frequently performed in Northeast Indian states such as Assam . The procedure has been reported to have some risk of complications, but is generally quite safe if done by an expert plastic surgeon. [ 7 ] Practitioners of East Asian blepharoplasty include plastic surgeons (facial plastic and reconstructive surgeons ), otolaryngologists , oral and maxillofacial surgeons , and ophthalmologists ( oculoplastic surgeons ). A procedure to remove the epicanthal fold (i.e., an epicanthoplasty ) is often performed in conjunction with an East Asian blepharoplasty. [ 8 ]
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The Eating Disorder Diagnostic Scale ( EDDS ) is a self-report questionnaire that assesses the presence of three eating disorders ; anorexia nervosa , bulimia nervosa and binge eating disorder . It was adapted by Stice et al. in 2000 from the validated structured psychiatric interview: The Eating Disorder Examination (EDE) and the eating disorder module of the Structured Clinical Interview for DSM-IV (SCID)16. [ 1 ]
A study was made to complete the EDDS research; the process to create and finalize the questionnaire. A group of people eating-disorders researchers take a looked at a preliminary version of the questionnaire and made a final decision of which questions to put on the final questionnaire with the 22 questions. [ 2 ] The questionnaire starts off with questions about the patient's feelings towards physical appearance, specifically weight. Then, it proceeds to questions about having episodes of eating with a loss of control and how the patient felt after overeating. The questions afterwards are about the patient's experience on fasting, making themselves vomit and using laxatives to prevent weight gain. It will then ask how much body image problems impact relationship and friendship with others. Lastly, the questionnaire asks for the patient's current weight, height, sex and age. [ 3 ]
The EDDS questionnaire is used for researchers to provide some cures for the three types of eating disorder. It is more efficient than having an interview because it is easier to get a result, from a group of participants, with the 22-item questionnaire. Having to interview each participant is a harder and more time-consuming way to get a result. This questionnaire is also useful for primary care/ clinical purposes to identify patients with eating pathology. [ 2 ]
In follow up studies of the reliability and validity of the EDDS, it was shown to be sufficiently sensitive to detect the effects of eating disorders prevention programs, response to such programs and the future onset of eating disorder pathology and depression . The EDDS shows both full and subthreshold diagnoses for anorexia nervosa, bulimia nervosa and binge eating disorder.
EDDS is a continuous eating disorder symptom composite score. [ 4 ] The PhenX Toolkit uses the EDDS for as an Eating Disorders Screener protocol. [ 5 ]
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Eating recovery refers to the full spectrum of care that acknowledges and treats the multiple etiologies of anorexia nervosa and bulimia , including the biological, psychological, social and emotional causes of the disorder, through a comprehensive, integrated treatment regimen. When successful, this regimen restores the individual to a healthy weight and arms them with the skills and resources needed to maintain a sustainable recovery. Although there are a variety of treatment options available to the eating disorders patient, the intensive and multi-faceted program followed in eating recovery is the appropriate option for individuals who require intensive support and are able to commit to treatment in an inpatient , residential or full-day hospital setting.
Eating recovery has been associated with increased likelihood of a sustained post-treatment recovery. This carefully orchestrated treatment curriculum incorporates the following tenets to help patients cultivate an understanding of disease-management skills and how to implement those lessons into their post-treatment lives.
Eating disorders are physically and emotionally destructive. Most individuals with an eating disorder require ongoing medical treatment throughout their recovery. According to the Eating Disorder Foundation, early diagnosis and intervention significantly enhance chances of recovery, while eating disorders that are not identified or treated in their early stages can become chronic, debilitating and life-threatening. [ 1 ]
For most people with eating disorders, the medical complications associated with the disease can be successfully treated with a combination of ongoing medical care and monitoring, nutritional counseling and medication. The Eating Disorder Foundation recommends people with eating disorders seek a recovery option that involves clinicians from different health disciplines, such as nursing, nutrition and mental health, a treatment philosophy consistent with the tenets of eating recovery. [ 2 ]
Medical issues associated with eating disorders. Extremely medically compromised patients who are at a very low weight will require a more intensive medical intervention. Anorexia patients with a very low body weight (BMI < 13) may need to be stabilized due to medical complications caused by starvation, including liver failure or heart problems. [ 3 ] Bulimia patients may need to manage edema , hypokalemia or esophagitis . [ 3 ]
Poor nutrition affects the brain’s chemicals and functionality. As a result, extremely low weight patients will have difficulty responding to cognitive therapy without first gaining weight. Medically supervised weight restoration is necessary before psychotherapy or many pharmaceuticals can affect the patient’s behavioral health.
Misdiagnosis of the medical complications of eating disorders is common due to the unique physiology of these patients. Eating disorders can slow a resting heart rate and lower a "normal" body temperature range. [ 3 ] For this reason, patients should seek specialized care from a doctor experienced in treating eating disorders.
During the process of eating recovery, patients integrate mindfulness into every area of their treatment. Mindfulness is a mental state, characterized by concentrated awareness of one's thoughts, actions or motivations. Being "present" in every element of treatment, including meals, therapy sessions, classes or medical treatment helps patients become more receptive to different points of view. It also helps them become less reactive to emotions, instead focusing only on activities occurring in the present moment.
Mindfulness training focused on eating, body image and body awareness can lead the way to health, and recovery by enabling individuals to consciously experience and observe their internal mental and bodily events as well as those external events that are perceived directly through the senses. In eating recovery, mindfulness helps patients calm their minds and understand their self-defeating emotions or mood-dependent behaviors and instead cultivate healthy coping skills. [ 4 ]
Mindfulness facilitates two key techniques— mentalizing and building self-awareness
Mentalization in eating recovery takes the concept of mindfulness one step further, often thought of as mindfulness of mind. Mentalization describes a person's ability to understand the mental state of themself and others based on overt behavior. Mentalization is a core challenge among people with eating disorders, and its lack can result in severe emotional fluctuations, impulsivity , and vulnerability to interpersonal and social interactions, particularly in the midst of emotional interaction. [ 5 ]
In eating recovery, patients work with their therapists to mentalize, or identify, their own emotions while understanding that others may hold differing points of view. The ability to understand emotions and see situations from more than one viewpoint reduces anxiety and minimizes the need to rely on an eating disorder as a coping mechanism. [ 1 ]
Self-awareness refers to an individual's ability to become aware of their own subconscious thinking. [ 6 ] Absence of self-awareness is frequently seen in eating disorder patients, causing them to react to situations, feelings and other stimuli emotionally rather than rationally.
By practicing mindful self-awareness, eating recovery learn to examine their thoughts, feelings, memories and bodily sensations from an objective point of view. Patients are encouraged to let go of self-centered thinking to achieve a state wherein individuals are able to observe their thoughts and understand their subconscious motivations—sexual, material, emotional, intellectual, and spiritual. This comprehension builds calmness and patience, minimizing the need to rely on an eating disorder as a coping mechanism. [ 1 ]
Motivation is the set of reasons that determines why and how individuals engage in particular behaviors. In eating recovery, the goal is to shift patients from emotion-motivated behavior to values-motivated behavior through self-directedness and the construction of values awareness. Patients learn to identify their own core values and direct themselves in behaviors that align with their value systems, while limiting behaviors that do not.
Driving self-directedness. Self-directedness is a dimension of a person's character which has to do with the ability of an individual to control, regulate, and adapt their behavior to the situation at hand in accordance with their own goals, purposes, and values. [ 7 ] An individual's inability to curtail eating disorder behaviors stems from low self-directedness. Eating recovery focuses on helping patients engage in self-directed behavior by giving their actions meaning within a values context.
Building values awareness. Self-directedness is difficult, if not impossible, without awareness of core values. Values provide the context for actions and feelings. Without awareness of values, people are often swayed by their emotional responses which may or may not serve their long-range goals and purposes. Under the sway of emotions, eating disorder behavior may become impulsive, "automatic", and mindless. [ 8 ]
In eating recovery, clinicians and therapists assist patients in identifying their core values. This approach allows patients to see the "big picture" and engage in behaviors that align with their core values while avoiding behaviors of a conflicting nature.
Chronic anxiety is a key trait of individuals with eating disorders, their lives consumed with coping with the emotions that result from anxiety. These emotion-driven moods often elicit negative coping behaviors and narrow the patient's awareness of coping options. These impulsive behaviors can drive mindless, rigid, stereotyped responses such those seen with eating disorders. [ 1 ]
In eating recovery, cognitive behavioral therapy and dialectical behavioral therapy are employed to interrupt negative cycles of behavior and replace them with positive, purposeful coping mechanisms.
Cognitive behavioral therapy' or CBT is a psychotherapeutic approach utilized in eating recovery that aims to influence dysfunctional emotions, behaviors and cognitions through a goal-oriented, systematic procedure. Cognitive-behavioral therapy is used to treat the mental and emotional elements of an eating disorder, helping patients change their attitudes about food, eating, and body image, correct poor eating habits, and prevent relapse. [ 9 ]
Dialectical behavioral therapy or DBT combines standard cognitive-behavioral techniques for emotion regulation and reality-testing with concepts of mindful awareness, distress tolerance , and acceptance in the treatment of eating disorders. Influenced by Buddhist meditative practice, DBT includes the following key elements: behaviorist theory, dialectics, cognitive therapy, and, DBT's central component, mindfulness.
According to the Eating Disorder Foundation, eating disorders are serious and complex illnesses that require the attention of trained professionals. Although those with the disease may have the desire, it is almost impossible for "self treatment" to be effective; in fact, trying to go it alone will likely result in repeated failures. Early detection and intervention has been proven to increase the chance of full recovery. It is essential for the person with the illness to get a professional assessment first, from a practitioner trained in eating recovery. [ 1 ]
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Ebb Cade (17 March 1890 – 13 April 1953) was a construction worker at Clinton Engineer Works in Oak Ridge, Tennessee , and was the first person subjected to injection with plutonium as an experiment.
Cade was born on 17 March 1890 in Macon County, Georgia , the son of Evens and Carrie Cade. Ebb Cade was married to Ida Cade. At age 63, Cade died as a result of ventricular fibrillation followed by heart failure on 13 April 1953 in Greensboro, North Carolina . [ 1 ]
On 23 March 1945 Cade was on his way to work at a construction site for the Manhattan Project when he was involved in a traffic accident at Oak Ridge, Tennessee . He was an African-American cement worker for the J.A. Jones Construction Company . Cade presented at the Oak Ridge Hospital with fractures of right patella , right radius and ulna and left femur . Dr. Hymer Friedell, deputy medical director of the Manhattan Engineer District, determined that as Cade was, as he characterized, a "well developed..well nourished" "colored male", he was suitable for "experimentation" with plutonium injection. Doctors left his fractures untreated for 20 days until after plutonium injections began on 10 April 1945. Cade received the injections at the Oak Ridge Hospital on the Clinton Engineer Works reservation without his consent or knowledge. He became known as HP-12 (Human Product-12) and was the first person to be injected with Plutonium-239 . [ 2 ] [ 3 ] In order to test the migration of plutonium through his body, subsequently 15 of Cade's teeth were extracted and bone samples taken. [ 4 ] [ 5 ]
According to one account, Cade departed suddenly from the hospital on his own initiative; one morning the nurse opened his door, and he was gone. Later it was learned that he moved out of state and died of heart failure in Greensboro. [ 6 ]
From 1945 to 1947, 18 people were part of a series of studies that involved the injection of plutonium. In Rochester, New York at Strong Memorial Hospital 11 people were injected. In Chicago, three individuals received injections at Billings Hospital of the University of Chicago . In San Francisco, California , three people were injected at the University Hospital of the University of California, San Francisco. The first person injected in California was Albert Stevens . [ 7 ] [ 8 ] [ 9 ] [ 10 ] Urine and feces samples were collected from the test subjects and forwarded to Los Alamos National Laboratory for plutonium analysis. [ 11 ] [ 12 ] The studies were utilized to formulate mathematical equations necessary to establish plutonium excretion rates. [ 13 ] [ 14 ] [ 15 ] [ 16 ]
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Ebullism is the formation of water vapour bubbles in bodily fluids due to reduced environmental pressure, usually at extreme high altitude . It occurs because a system of liquid and gas at equilibrium will see a net conversion of liquid to gas as pressure lowers; for example, liquids reach their boiling points at lower temperatures when the pressure on them is lowered. [ 1 ] The injuries and disorder caused by ebullism is also known as ebullism syndrome . [ 2 ] Ebullism will expand the volume of the tissues, but the vapour pressure of water at temperatures in which a human can survive is not sufficient to rupture skin or most other tissues encased in skin. [ 3 ] Ebullism produces predictable injuries, which may be survivable if treated soon enough, and is often accompanied by complications caused by rapid decompression, such as decompression sickness and a variety of barotrauma injuries. Persons at risk are astronauts and high altitude aviators, for whom it is an occupational hazard . [ 1 ]
Symptoms of ebullism include bubbles in the membranes of the mouth and eyes, swelling of the soft tissues with possible bruising, and bubbles in the blood. Blood circulation and breathing may be impaired or stopped by cardiac vapourlock. The brain tissue may be starved of oxygen because of blockage of arteries resulting in rapid loss of consciousness, and the lungs may swell and hemorrhage . Death results unless recompression is rapid enough to restore oxygenation and reduce the bubbles before excessive tissue damage occurs. [ 4 ] [ 3 ] Head exposure may result in freezing of the corneal surface of the eye, impairing vision. [ 5 ] Other signs and symptoms of rapid decompression injury may also be present. [ 1 ]
A decompression event leading to ebullism will cause acute anoxemia and is likely to cause other decompression injuries such as decompression sickness and possibly one or more forms of decompression barotrauma. [ 6 ]
In the atmospheric pressure present at sea level , water boils at 100 °C (212 °F). At an altitude of 63,000 feet (19,000 m), it boils at only 37 °C (99 °F), the normal body temperature of humans. This altitude is known as Armstrong's Line . [ 7 ] Ebullism occurs when unprotected humans are exposed to altitudes above the Armstrong limit where the vapor pressure of tissues is less than the ambient pressure. [ 5 ] In practice bodily fluids do not boil off continuously at this altitude because the skin and outer organs have enough strength to withstand the internal pressure, [ 8 ] so the pressure inside the tissues would increase to match vapour pressure. Nitrogen dissolved in the tissues may also accumulate in the vapour bubbles causing altitude decompression sickness . [ 5 ]
Pathophysiology of ebullism has mostly been studied in animals, including large primates, but no reasons have been found to suggest that the results should not be reasonably extrapolated to predict effects on humans. The experiments show that ebullism occurs non-uniformly at sites where conditions are most conducive to vapourisation of water and outgassing of nitrogen. Factors include temperature, hydrostatic pressure, tissue elasticity, solute concentration, and the presence of gas bubble nuclei, and which can cause vapour bubbles to form at pressures slightly above the theoretical ambient pressure of 47 millimetres of mercury (63 mbar) in some places such as the pleural cavity, where the pressure can drop below ambient, and large central veins where hydrostatic pressure is minimum and blood temperature is at a maximum. [ 6 ]
Ebullism occurs as a consequence of exposure to ambient pressures below about 47 millimetres of mercury (63 mbar). At higher pressures similar symptoms are likely to be caused by decompression sickness and some forms of barotrauma. [ 1 ]
To prevent ebullism, the tissues must be kept under sufficient pressure that vaporisation of the aqueous constituents is not possible in the range of temperature those tissues may experience. [ 1 ]
An effective strategy for preventing ebullism would include multiple redundant levels of protection against decompression, and systems allowing non-catastrophic failure with sufficient time of useful consciousness to take effective countermeasures. Several mitigating strategies have associated hazards of their own. A high concentration of oxygen in the breathing gas reduces the severity of decompression sickness complications and may increase the duration of useful consciousness, but at the same time increases fire hazard. A low initial pressure reduces decompression rate and severity in a catastrophic decompression, which reduces the risk of barotrauma but gives a lower margin of safety in a slow decompression, and can increase the risk of decompression sickness. Outside of a pressurised cabin environment, a pressure suit is the usual protective measure, and is the definitive protection in decompression to vacuum, but they are expensive, heavy, bulky, restrict mobility, cause thermal regulatory problems, and reduce comfort. [ 1 ]
Ebullism produces secondary tissue damage which, when extensive, has generally been considered fatal due to limited availability of treatment options on site. Immediate recompression to a pressure at minimum pressure for effective oxygenation is necessary for survival in whole-body exposure, along with re-oxygenation. Continued or additional pressurisation where necessary to prevent or treat decompression sickness is also indicated. [ 1 ]
High-frequency percussive ventilation is recommended by Murray et al (2013) for respiratory support as atelectasis is likely. [ 1 ]
Initial field evaluation would be
similar to trauma assessment. It may be necessary to remove a pressure suit to give access for primary and secondary surveys. Airway, breathing, and circulation are immediate priorities, followed by assessment of level of consciousness. Intubation is indicated if unconscious and deteriorating.
If a pulse cannot be distinguished, and the person is unresponsive, cardiopulmonary resuscitation should be started immediately, with advanced cardiac life support and cardiovascular monitoring as soon as possible. [ 1 ]
Little information is available on the effectiveness of conventional treatment, such as hyperbaric oxygen , or adjunctive therapies , for injuries due to ebullism. [ 5 ] Spontaneous recovery has occurred in cases where recompression was applied with minimal delay, or the damage was restricted to parts of the limbs. Other examples were fatal. [ 9 ]
The time needed for recovery will depend on the severity of injury, which is largely dependent on severity and duration of exposure. The main predictor of survival is the establishment of sufficient circulation and breathing. [ 1 ]
Ebullism risk is associated with spaceflight, particularly EVA accidents, rapid decompression of aircraft at very high altitudes, and pressure suit failure during flight and training exercises. [ 5 ]
In 1960, Joseph Kittinger experienced localised ebullism during a 31 kilometres (19 mi) ascent in a helium -supported gondola. [ 10 ] His right-hand glove failed to pressurise and his hand expanded to roughly twice its normal volume [ 11 ] [ 12 ] accompanied by disabling pain. His hand took about three hours to recover after his return to the ground.
Tissue samples from the remains of the crew of Space Shuttle STS-107 Columbia revealed evidence of ebullism. Given the level of tissue damage, the crew could not have regained consciousness even with re-pressurization. [ 9 ]
The term "space ebullism" was introduced by Captain Julian E. Ward in his paper "The True Nature of the Boiling of Body Fluids in Space", published in Aviation Medicine in October 1956. It was suggested "because the word ebullism does not connote the addition of heat to produce vapor." It comes from the Latin ebullire , meaning "to bubble out, or to boil up." [ 13 ] [ 14 ]
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Echocardiography , also known as cardiac ultrasound , is the use of ultrasound to examine the heart . It is a type of medical imaging , using standard ultrasound or Doppler ultrasound . [ 1 ] The visual image formed using this technique is called an echocardiogram , a cardiac echo , or simply an echo .
Echocardiography is routinely used in the diagnosis, management, and follow-up of patients with any suspected or known heart diseases . It is one of the most widely used diagnostic imaging modalities in cardiology. It can provide a wealth of helpful information, including the size and shape of the heart (internal chamber size quantification), pumping capacity, location and extent of any tissue damage, and assessment of valves. An echocardiogram can also give physicians other estimates of heart function, such as a calculation of the cardiac output , ejection fraction , and diastolic function (how well the heart relaxes).
Echocardiography is an important tool in assessing wall motion abnormality in patients with suspected cardiac disease. [ 2 ] It is a tool which helps in reaching an early diagnosis of myocardial infarction , showing regional wall motion abnormality. Also, it is important in treatment and follow-up in patients with heart failure , by assessing ejection fraction . [ 2 ] [ 3 ]
Echocardiography can help detect cardiomyopathies , such as hypertrophic cardiomyopathy , and dilated cardiomyopathy. The use of stress echocardiography may also help determine whether any chest pain or associated symptoms are related to heart disease.
The most important advantages of echocardiography are that it is not invasive (does not involve breaking the skin or entering body cavities) and has no known risks or side effects. [ 4 ]
Not only can an echocardiogram create ultrasound images of heart structures, but it can also produce accurate assessment of the blood flowing through the heart by Doppler echocardiography, using pulsed- or continuous-wave Doppler ultrasound. This allows assessment of both normal and abnormal blood flow through the heart. Color Doppler, as well as spectral Doppler, is used to visualize any abnormal communications between the left and right sides of the heart, as well as any leaking of blood through the valves (valvular regurgitation), and can also estimate how well the valves open (or do not open in the case of valvular stenosis). The Doppler technique can also be used for tissue motion and velocity measurement, by tissue Doppler echocardiography .
Echocardiography was also the first ultrasound subspecialty to use intravenous contrast. Echocardiography is performed by cardiac sonographers , cardiac physiologists (UK), or physicians trained in echocardiography.
Recognized as the "Father of Echocardiography", the Swedish physician Inge Edler (1911–2001), a graduate of Lund University , was the first of his profession to apply ultrasonic pulse echo imaging in diagnosing cardiac disease, which the acoustical physicist Floyd Firestone had developed to detect defects in metal castings. In fact, Edler in 1953 produced the first echocardiographs using an industrial Firestone-Sperry Ultrasonic Reflectoscope. In developing echocardiography, Edler worked with the physicist Carl Hellmuth Hertz , the son of the Nobel laureate Gustav Hertz and grandnephew of Heinrich Rudolph Hertz . [ 5 ] [ 6 ]
Health societies recommend the use of echocardiography for initial diagnosis when a change in the person's clinical status occurs and when new data from an echocardiogram would result in the physician changing the person's care. [ 7 ] Diagnostic criteria for numerous cardiac diseases are based on echocardiography studies. For example, the differentiation of mild, moderate, and severe valvular disease is based upon measured criteria. [ 8 ] Another example is the estimation of heart function by the left ventricular ejection fraction (LVEF) has vast uses including classification of heart failure and cut offs for implantation of implantable cardioverter-defibrillators . [ citation needed ]
Health societies do not recommend routine testing when the patient has no change in clinical status or when a physician is unlikely to change care for the patient based on the results of testing. [ 7 ] A common example of overuse of echocardiography when not indicated is the use of routine testing in response to a patient diagnosis of mild valvular heart disease . [ 9 ] In this case, patients are often asymptomatic for years before the onset of deterioration and the results of the echocardiogram would not result in a change in care without other change in clinical status. [ 9 ]
Echocardiography has a vast role in pediatrics , diagnosing patients with valvular heart disease and other congenital abnormalities. An emerging branch is fetal echocardiography , which involves echocardiography of an unborn fetus. [ citation needed ]
There are three primary types of echocardiography: transthoracic, transesophageal, and intracardic.
Stress testing utilizes tranthoracic echo in combination with an exercise modality (e.g., a treadmill).
Intravascular ultrasound is included below, but is as the name indicates more "ultrasound" than "echocardiography" as it is imaging the walls of a vessel rather than the heart.
A standard echocardiogram is also known as a transthoracic echocardiogram (TTE) or cardiac ultrasound, and it is used for rapid evaluation of a patient at their bedside. [ 10 ] [ 11 ] In this case, the echocardiography transducer (or probe) is placed on the chest wall (or thorax ) of the subject, and images are taken through the chest wall. This is a non-invasive, highly accurate, and quick assessment of the overall function of the heart.
TTE utilizes several "windows" to image the heart from different perspectives. Each window has advantages and disadvantages for viewing specific structures within the heart and, typically, numerous windows are utilized within the same study to fully assess the heart. Parasternal long and parasternal short axis windows are taken next to the sternum, the apical two/three/four chamber windows are taken from the apex of the heart (lower left side), and the subcostal window is taken from underneath the edge of the last rib.
TTE utilizes one- ("M mode"), two-, and three-dimensional ultrasound (time is implicit and not included) from the different windows. These can be combined with pulse wave or continuous wave Doppler to visualize the velocity of blood flow and structure movements. Images can be enhanced with "contrast" that are typically some sort of micro bubble suspension that reflect the ultrasound waves.
A transesophageal echocardiogram is an alternative way to perform an echocardiogram. A specialized probe containing an ultrasound transducer at its tip is passed into the patient's esophagus via the mouth, allowing image and Doppler evaluation from a location directly behind the heart. It is most often used when transthoracic images are suboptimal and when a clearer and more precise image is needed for assessment. This test is performed in the presence of a cardiologist, anesthesiologist, registered nurse, and ultrasound technologist. Conscious sedation and/or localized numbing medication may be used to make the patient more comfortable during the procedure.
TEE, unlike TTE, does not have discrete "windows" to view the heart. The entire esophagus and stomach can be utilized, and the probe advanced or removed along this dimension to alter the perspective on the heart. Most probes include the ability to deflect the tip of the probe in one or two dimensions to further refine the perspective of the heart. Additionally, the ultrasound crystal is often a two-dimension crystal and the ultrasound plane being used can be rotated electronically to permit an additional dimension to optimize views of the heart structures. Often, movement in all of these dimensions is needed.
TEE can be used as stand-alone procedures, or incorporated into catheter- or surgical-based procedures. For example, during a valve replacement surgery the TEE can be used to assess the valve function immediately before repair/replacement and immediately after. This permits revising the valve mid-surgery, if needed, to improve outcomes of the surgery.
A stress echocardiogram, also known as a stress echo, uses ultrasound imaging of the heart to assess the wall motion in response to physical stress. First, images of the heart are taken "at rest" to acquire a baseline of the patient's wall motion at a resting heart rate. The patient then walks on a treadmill or uses another exercise modality to increase the heart rate to his or her target heart rate, or 85% of the age-predicted maximum heart rate (220 − patient's age). Finally, images of the heart are taken "at stress" to assess wall motion at the peak heart rate. A stress echo assesses wall motion of the heart; it does not, however, create an image of the coronary arteries directly. Ischemia of one or more coronary arteries could cause a wall motion abnormality, which could indicate coronary artery disease. The gold standard test to directly create an image of the coronary arteries and directly assess for stenosis or occlusion is a cardiac catheterization. A stress echo is not invasive and is performed in the presence of a licensed medical professional, such as a cardiologist, and a cardiac sonographer.
Intracardiac echocardiography (ICE) is specialized form of echocardiography that uses catheters to insert the ultrasound probe inside the heart to view structures from within the heart.
ICE is often used as a part of the cardiac procedure of crossing the interatrial septum with a transseptal puncture to permit catheter access from the right atrium to the left atrium; alternative access to the left heart would be retrograde through the aorta and across the aortic valve into the left ventricle.
ICE has the benefit over transthoracic echocardiography in that an operator who is performing a sterile procedure can also operate the ICE catheter and it is not limited to visibility problems that can arise with transthoracic or transesophageal echo. Though, there are image quality limitations due to size constraints of the probe being limited to a catheter.
ICE is often inserted through the femoral vein and into the right atrium.
From the right atrium, visualization of the interatrial septum, all four cardiac chambers, all four valves, and the pericardial space (for an effusion) can be readily visualized.
It can also be advanced across the atrial septum into the left atrium to visualize the left atrial appendage during left atrial appendage occlusion device deployment.
Utilization of ICE imagery can be incorporated into the 3-D models built with electroanatomic mapping systems.
Intravascular ultrasound (IVUS) is a specialized form of echocardiography that uses a catheter to insert the ultrasound probe inside blood vessels. This is commonly used to measure the size of blood vessels and to measure the internal diameter of the blood vessel. For example, this can be used in a coronary angiogram to assess the narrowing of the coronary artery. If the catheter is retraced in a controlled manner, then an internal map can be generated to see the contour of the vessel and its branches.
The various modes describe how the ultrasound crystals are used to obtain information. These modes are common to all types of echocardiography.
A-scan or one dimensional ultrasound represents over half the standard ECHO exam. For example, it is how aortic stenosis valve area (or any obstruction). It is also how pressures are calculated in the heart such as right ventricle systolic pressure (RVSP). It is usually used in the form of Doppler measurements. There are two forms, pulse and continuous. Pulsed allows velocities to be calculated in a specific place, but has a limited velocity range is can be used. Continuous wave allows the velocity to be measured from zero to the fastest blood velocities a diseased heart can generate. However, it can not tell you where in the A-scan the high velocity is coming from. Continuous wave would be used to calculate aortic stenosis because you know the high velocity is coming from the stenosis region. Pulsed would be used to find a ventricular septal defect where there should be no velocity across the septum and the pulsed tells you the location.
Brightness mode is often synonymous with "2D" and is very commonly used in echocardiography.
Motion mode, though less commonly used, plays an important role in modern echocardiography. It has an advantage over 2D echocardiography due to its high temporal resolution (up to 1000 frames/sec). Examples of its use include accurate measurement of LV size, assessment for presence of cardiac tamponade, and assessment of RV function with TAPSE (tricuspid annular systolic plane excursion).
Strain rate imaging is an ultrasound method for imaging regional differences in contraction (dyssynergy) in for instance ischemic heart disease or dyssynchrony due to Bundle branch block . Strain rate imaging measures either regional systolic deformation (strain) or the rate of regional deformation (strain rate). The methods used are either tissue Doppler or Speckle tracking echocardiography .
Three-dimensional echocardiography (also known as four-dimensional echocardiography when the picture is moving) is possible using a matrix array ultrasound probe and an appropriate processing system. It enables detailed anatomical assessment of cardiac pathology, particularly valvular defects, [ 12 ] and cardiomyopathies. [ 13 ] The ability to slice the virtual heart in infinite planes in an anatomically appropriate manner and to reconstruct three-dimensional images of anatomic structures make it unique for the understanding of the congenitally malformed heart. [ 14 ] Real-time three-dimensional echocardiography can be used to guide the location of bioptomes during right ventricular endomyocardial biopsies, placement of catheter-delivered valvular devices, and in many other intraoperative assessments. [ 15 ]
Three-dimensional echocardiography technology may feature anatomical intelligence, or the use of organ-modeling technology, to automatically identify anatomy based on generic models. All generic models refer to a dataset of anatomical information that uniquely adapts to variability in patient anatomy to perform specific tasks. Built on feature recognition and segmentation algorithms, this technology can provide patient-specific three-dimensional modeling of the heart and other aspects of the anatomy, including the brain, lungs, liver, kidneys, rib cage, and vertebral column. [ 16 ]
Contrast echocardiography or contrast-enhanced ultrasound is the addition of an ultrasound contrast medium, or imaging agent, to traditional ultrasonography. The ultrasound contrast is made up of tiny microbubbles filled with a gas core and protein shell. This allows the microbubbles to circulate through the cardiovascular system and return the ultrasound waves, creating a highly reflective image. There are multiple applications in which contrast-enhanced ultrasound can be useful. The most commonly used application is in the enhancement of LV endocardial borders for assessment of global and regional systolic function. Contrast may also be used to enhance visualization of wall thickening during stress echocardiography, for the assessment of LV thrombus, or for the assessment of other masses in the heart. Contrast echocardiography has also been used to assess blood perfusion throughout myocardium in the case of coronary artery disease.
Echocardiography can at many times be subjective, meaning that the person reading the echo may have personal input that affects the interpretation of the findings, leading to so-called "inter-observer variability", where different echocardiographers might produce different reports when examining the same images. [ 17 ] [ 18 ] It necessitated the development of accreditation programs around the world. The aim of such programs is to standardize the practice of echocardiography and to ensure that practitioners have the proper training prior to practicing echocardiography which will eventually limit inter-observer variability. [ 19 ]
At the European level [ 20 ] individual and laboratory accreditation is provided by the European Association of Echocardiography (EAE). There are three subspecialties for individual accreditation: Adult Transthoracic Echocardiography ( TTE ), Adult Transesophageal Echocardiography ( TEE ) and Congenital Heart Disease Echocardiography (CHD).
In the UK, accreditation is regulated by the British Society of Echocardiography. Accredited radiographers, sonographers, or other professionals are required to pass a mandatory exam. [ 21 ]
The "Intersocietal Accreditation Commission for Echocardiography" (IAC) sets standards for echo labs across the US. Cardiologists and sonographers who wish to have their laboratory accredited by IAC must comply with these standards. The purpose of accreditation is to maintain quality and consistency across echocardiography labs in the United States. Accreditation is offered in adult and pediatric transthoracic and transesophageal echocardiography, as well as adult stress and fetal echo. Accreditation is a two-part process. Each facility will conduct a detailed self-evaluation, paying close attention to the IAC Standards and Guidelines. The facility will then complete the application and submit actual case studies to the board of directors for review. Once all requirements have been met, the lab will receive certification. IAC certification is a continual process and must be maintained by the facility: it may include audits or site visits by the IAC. There are several states in which Medicare and/or private insurance carriers require accreditation (credentials) of the laboratory and/or sonographer for reimbursement of echocardiograms.
There are two credentialing bodies in the United States for sonographers, the Cardiovascular Credentialing International (CCI), established in 1968, and the American Registry for Diagnostic Medical Sonography (ARDMS), established in 1975. Both CCI and ARDMS have earned the prestigious ANSI-ISO 17024 accreditation for certifying bodies from the International Organization for Standardization ( ISO ). [ citation needed ] Accreditation is granted through the American National Standards Institute (ANSI). Recognition of ARDMS programs in providing credentials has also earned the ARDMS accreditation with the National Commission for Certifying Agencies (NCCA). The NCCA is the accrediting arm of the National Organization for Competency Assurance (NOCA).
Under both credentialing bodies, sonographers must first document completion of prerequisite requirements, which contain both didactic and hands-on experience in the field of ultrasound. Applicants must then take a comprehensive exam demonstrating knowledge in both the physics of ultrasound and the clinical competency related to their specialty. Credentialed sonographers are then required to maintain competency in their field by obtaining a certain number of Continuing Medical Education credits, or CME's.
In 2009, New Mexico and Oregon became the first two states to require licensure of sonographers. [ citation needed ]
The American Society of Echocardiography (ASE) is a professional organization made up of physicians, sonographers, nurses, and scientists involved in the field of echocardiography. One of the most important roles that the ASE plays is providing their recommendations through the ASE Guidelines and Standards, providing resource and educational opportunities for sonographers and physicians in the field.
There have been various institutes who are working on use of Artificial intelligence in Echo but they are at a very early stage and still needs full development. [ 22 ]
The most commonly used terminology in echocardiography diagnostics are:
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Ecnoglutide (XW003) is a GLP-1 agonist being developed for the treatment of obesity and type 2 diabetes . [ 1 ] [ 2 ] [ 3 ] In preclinical trials, "Ecnoglutide showed a favorable potency, pharmacokinetic, and tolerability profile, as well as a simplified manufacturing process" compared to other GLP-1 agonists. [ 4 ]
This medical article is a stub . You can help Wikipedia by expanding it .
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Eco-friendly dentistry (also called environmentally friendly dentistry , green dentistry or sustainable dentistry ) aims at reducing the detrimental impact of dental services on the environment while still being able to adhere to the regulations and standards of the dental industries in their respective countries.
There are no official governing agencies that certify an office as meeting eco-friendly standards. Dental offices in the United States of America can be recognised as eco-friendly offices by becoming members of the Eco Dentistry Association . Within England there are audit programmes available from the National Union of Students such as the Green Impact tool. [ 1 ] People who want to be involved and discuss sustainable dentistry in a free and open forum are invited to be members at the Centre for Sustainable Healthcare. [ 2 ]
The term eco-friendly dentistry has roots originating from the environmental movement and environmentalism , which, in the Western world, is often perceived as having begun in the 1960s and 1970s. The rise of this movement is often credited to Rachel Carson , [ 3 ] conservationist and author of the book Silent Spring . Subsequently, legislation in many countries throughout the world began gaining momentum in the 1970s and continues to the present day. [ 4 ]
Eco-friendliness also has meaning in another context as a marketing term. It is used by companies to appeal to consumers of goods and services as having a low impact on the environment. [ 5 ] Market research has found that an increasing number of consumers purchase goods and services that appeal to the values of environmental philosophy. [ 6 ] The dental industry has adopted the concept of eco-friendliness both in a well-meaning, philosophical context and as a marketing term so that patients who subscribe to principles of sustainability can choose to visit these offices.
The term has been criticised as being used for " greenwashing ", which is the practice of deceptively promoting a product or service as environmentally friendly. Legislation in countries around the world have Trade Commissions and such to stop companies profiting with baseless claims on their goods and services. [ citation needed ] Individuals and bodies that work in the dental industry have also subsequently adopted the principles of sustainability and environmentalism and also as an advertisement to patients, clients and consumers. The Eco Dentistry Association is an accreditation organisation in the United States which has proposed outcomes towards becoming more sustainable.
In 2008, the Eco Dentistry Association (EDA) was co-founded by Dr. Fred Pockrass and his wife, Ina Pockrass. The EDA provides "education, standards and connection" to patients and dentists who practice green dentistry. The EDA aims to help dentists "come up with safe and reusable alternatives that lower a dentists' operating cost by replacing paper with digital media whenever possible." [ 7 ] As of February 2011, the EDA has approximately 600 members. [ 7 ] After the inception of the EDA, the dental industry in America saw more dentists and oral surgeons choosing to make their offices environmentally friendly. [ 8 ]
In 2011, The Australian Dental Association implemented a policy of sustainability to provide guidelines to assist in the environmental sustainability of dental offices in Australia. [ 9 ] In August 2017 the FDA adopted a sustainability in dentistry policy. [ 10 ]
There is a growing amount of scientific information regarding the carbon footprint of the dental industry. These include papers by Duane relating to work carried out in Scotland and more recently England. [ 11 ] [ 12 ] [ 13 ]
Recently, Public Health England published a report on the carbon footprint of NHS England dentistry. [ 14 ] The report based on 2014 data provides a number of recommendations for the dental team in England to consider. The report demonstrated the considerable contribution of staff and patient travel to the overall carbon footprint.
To be environmentally responsible, offices can incorporate the four R's of environmental responsibility. The four R's are: reduce, reuse, recycle and rethink. [ 15 ]
Having a paperless dental office reduces or eliminates the use of paper by going digital. This involves converting patient files, medical histories and other documentation to an electronic system. Going paperless not only makes information sharing easier and accessible but is a great way of keeping personal information secure. This saves money, boosts productivity and saves space as there is no need for any filing cabinets and is a great way of ensuring clinical records are more accurate. [ 15 ] Using digital radiography allows to keep all the patients' records in one spot, reduces the amount of radiation exposure and images and clinical photographs can be shared without losing the quality of the image. [ 15 ]
In many countries around the world there are strict mandatory limits on the use of mercury and the levels found in wastewater.
Mercury is traditionally used in dental restorations known as amalgam. In October 2013, Australia's Department of the Environment and Energy signed The Minamata Convention in a call for the reduction of amalgam usage by means of nine measures aiming to eventually phase out the use of amalgam. [ 16 ] Mercury can be released into the environment when amalgam is placed, finished and polished or removed from a patient mouth and can be either rinsed into sewage systems or disposed of in landfill. By complying with the Australian Dental Association (ADA) Policy 6.11 [ 17 ] and the current edition of the International Organization for Standardization ISO11143 Dentistry – Amalgam Separators, [ 18 ] reducing the amount of mercury entering the environment by means of installing amalgam separators and traps to collect and separate amalgam waste before it enters the sewage system. Amalgam that is collected from traps is then collected and recycled for reuse. [ 9 ]
With the phasing out of manual processing of radiographs and switching to digital radiography allows for offices not having to purchase developing liquids and these liquids are harmful to the environment and need to be collected to be disposed of correctly. [ 19 ] [ 17 ] [ 9 ]
• Installing a water meter to monitor water usage. • Handwashing sinks with motion-activated taps . • Collect the water bills for the last year to benchmark a water usage audit. • Place interpretive signs about water conservation in staff rooms, toilets and surgeries. • Maintain and repair taps or fittings. [ 20 ] • Use a non-water-based approach to cleaning where possible. • Retro flow controllers in key usage areas. [ 20 ] • Install 4-, 5- or 6-star water efficient appliances where appropriate.
Dental practices can recycle paper , cardboard, aluminum and plastics from plastic barriers and other water products contributing to sustainable environmentally friendly practices. Autoclave bags can be separated after opening and the paper and plastic recycled separately.
To become more eco-friendly or environmentally friendly dental practices can purchase biodegradable products therefore allowing more waste associated with the running of the practice to be recycled. Shredding of paper documents and recycling shredded paper will contribute to sustainable practices.
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Economic credentialing is a term of disapproval used by the American Medical Association (AMA). The association defines the term as "the use of economic criteria unrelated to quality of care or professional competence in determining a physician's qualifications for initial or continuing hospital medical staff membership or privileges."
Traditionally, physicians applied for hospital staff membership based on education , medical licensure and a record of quality care. Privileges are requests to perform certain procedures or use certain skills based on training and experience. For example, an obstetrician and a family practitioner might request privileges for both routine deliveries and caesarean sections . Typically an obstetrician could demonstrate enough experience and be granted those privileges. The FP might obtain both procedures or be restricted to routine deliveries only, or none at all, based on hospital policy.
As medical costs have increased and reimbursement has declined or been stagnant, both hospitals and physicians have come under increasing financial pressure. One response by physicians has been the formation of specialty hospitals or diagnostic centers with physician ownership. Some hospitals have seen this as a threat to their economic interests and have denied or revoked membership and privileges of the physician owners.
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Ecovative LLC is a materials company headquartered in Green Island, New York , that provides sustainable alternatives to plastics and polystyrene foams for packaging , building materials as well as farm harvested high performance mycelium materials and proteins to reduce animal agriculture.
Ecovative was developed from a university project of founders Eben Bayer and Gavin McIntyre. In their Inventor's Studio course at Rensselaer Polytechnic Institute taught by Burt Swersey, Eben and Gavin developed and then patented a method of growing a mushroom-based insulation, initially called Greensulate before founding Ecovative Design in 2007. [ 1 ] [ 2 ] In 2007 they were awarded $16,000 from the National Collegiate Inventors and Innovators Alliance . [ 3 ]
Since 2008, when they were awarded $700,000 first place in the Picnic Green Challenge [ 4 ] the company has developed and commercialized production of a protective packaging called EcoCradle [ 5 ] that is now used by Dell , Puma SE , and Steelcase . In 2010 they were awarded $180,000 from the National Science Foundation [ 6 ] and in 2011 the company received investment from 3M New Ventures, The DOEN Foundation , and Rensselaer Polytechnic Institute allowing them to double their current staff of 25. [ 7 ]
In spring 2012, Ecovative Design opened a new production facility and announced a partnership with Sealed Air to expand production of the packaging materials. [ 8 ] [ 9 ] In 2014 their material was used in a brick form in 'Hy-Fi', a 40-foot (12 m) tower displayed in New York by the Museum of Modern Art and they started selling "grow-it-yourself" kits. [ 10 ]
In November 2019, the company announced a $10M investment to support their new Mycelium Foundry. [ 11 ]
In February 2020, IKEA committed to using Ecovative technology for packaging, replacing polystyrene. [ 12 ]
In April 2021, Ecovative Design received a $60M investment to develop new applications for their technology and scale up manufacturing. [ 13 ]
Mushroom composite materials are a novel class of renewable bio-material grown from fungal mycelium and low-value non-food agricultural materials, like shredded hemp stalks, corn husks, soybean hulls and more, using a patented process developed by Ecovative in 2007. Ecovative's legacy technology, MycoComposite, is the basis for sustainable protective packaging, building and construction insulation, automotive and aerospace components and even surfboards.
The entire process to grow MyComposite takes 7 days. nce the mycelium has been mixed with the chosen substrate it is left to grow in a form in a dark room at ambient room temperature for about five days, during which time the fungal mycelial network binds the agricultural substrate together resulting in light, robust and organic home compostable material that can be used within many products, including building materials , thermal insulation panels and protective packaging . [ 14 ] The product is rendered inert through a baking process in a kiln that stops the mycelium from growing further once the desired outcome is achieved.
The environmental footprint of the products is minimized through the use of agricultural waste, reliance on natural and non-controlled growth environments, and home compostable final products. [ 15 ] The founders' intention is that this technology should replace polystyrene and other petroleum-based products that take many years to decompose, or release toxic forever chemicals . [ 7 ]
A renewable and compostable replacement for polystyrene packaging, [ 16 ] that was originally called 'EcoCradle. [ 17 ] The name was changed to Mushroom Packaging in 2012 and it is now grown by licensees of the technology globally. Ecovative still makes this product available under license in the United States and it is available to order through their mycelium materials website www.grow.bio.
A natural and renewable replacement for engineered wood , formed from compressed mushroom material and requiring no numerical control . [ 18 ] Architect David Benjamin of The Living, working with Ecovative and Arup , built 'Hy-Fi', a temporary 40 feet (12 m) external exhibit at the Museum of Modern Art in New York City in 2014. [ 19 ] [ 20 ] David Benjamin and Ecovative then collaborated again on an Autodesk project in 2024 for the City of Oakland to construct a 130+ unit affordable housing building in the heart of the city. Through environmental testing it was found that the mycelium composite Ecovative grew for the exterior panels made the project Carbon Negative thanks to the substrate that was chosen making the building a large carbon sink . MycoComposite panels also benefit construction projects as they are sound deadening as well.
In 2012, scientists and engineers at Ecovative partnered with the EPA to grow a pure mycelium foam with the intention of using it for a shoe sole alternative to plastic. The experimentation in the lab for this project led to the discovery of Ecovative's latest technology platform, AirMycelium.
Ecovative's AirMycelium Platform utilizes existing mushroom farming infrastructure, specifically Dutch Style Mushroom Grow Chambers, utilizing over 3 billion lbs of existing global mushroom farming infrastructure. This platform enables the production of organic oyster mushroom mycelium proteins for meatless meats, elastomeric foams and high performance textiles often referred to globally as Mushroom Leather .
MyBacon
Ecovative's flagship breakfast protein is MyBacon currently in distribution in the United States from Ecovative's spinout company MyForest Foods - established in 2020. MyBacon is available in Whole Foods, Fairway Markets, Earth Fare, Hungry Root, Fresh Direct, Good Eggs, celebrity favorite grocer Erewon and independent grocers.
Forager Foams and Hides
In 2021, Ecovative launched Forager to bring high performance mycelium textiles and mycelium foams to the fashion, automotive and aerospace industries. Working with brands like PVH Corp (the parent company of Tommy Hilfiger and Calvin Klein ), Reformation, Wolverine World Wide and ECCO Leather.
Ecovative offer a 'Grow-it-yourself' kit allowing people to create mushroom materials themselves, used to create products including lamp shades. [ 10 ] These can be ordered through their mycelium supply website www.grow.bio.
Working with the University of Aachen , Dutch designer Eric Klarenbeek used 3D printing technology to gown a chair without using plastic, metal or wood. [ 21 ]
Popular Science featured the composite insulation in its 2009 Invention Awards. [ 22 ] A season six episode of CSI: New York , also featured the insulation as lab technicians tested the materials' flame resistant properties after finding particles on a victim's clothing. [ 23 ] Packaging World magazine featured Ecovative on its July 2011 cover, suggesting that the company is poised to "be a game changer in various industries." [ 24 ] [ 25 ] The World Economic Forum also recognized Ecovative as a Technology Pioneer in 2011. [ 26 ] Additionally, the founders were featured on the PBS show, Biz Kid$ , in episode 209, "The Green Economy & You." [ 27 ]
Since 2019 Ecovative has been feature in the Histoy of the Future on PBS - Season1 Episode 2, Merlin Sheldrakes book Entangled Life, as well as the documentary Web of Life.
The development of the material and processes has been supported by the Picnic Green Challenge, the Environmental Protection Agency , National Collegiate Inventors and Innovators Alliance (NCIIA), ASME , the National Science Foundation , NYSERDA , 3M New Ventures, The DOEN Foundation, Rensselaer Polytechnic Institute and a license agreement with Sealed Air. [ 7 ] [ 28 ] In addition to an array of awards, Ecovative's materials have been extensively highlighted in Material ConneXion libraries around the world. [ 29 ]
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Ectopic enamel is an abnormality in the formation of enamel. It is tooth enamel that is found in an unusual location ( ectopia ), such as at the root of a tooth. [ 1 ] Enamel pearls are a type of ectopic enamel. [ 2 ]
This dentistry article is a stub . You can help Wikipedia by expanding it .
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An ectopic pancreas is an anatomical abnormality in which pancreatic tissue has grown outside its normal location ( ectopia ) and without vascular or other anatomical connections to the pancreas. [ 2 ] It is a disease which is congenital [ 2 ] and is also known as heterotopic, accessory, or aberrant pancreas. [ 3 ]
Often, heterotopic pancreas is asymptomatic . When present, symptoms may include abdominal pain and distension. [ 1 ] Heterotopic pancreas is commonly recognized as an incidental finding on imaging studies performed for an unrelated reason.
Ectopic pancreatic tissue may occur anywhere in the abdominal cavity, though more than 90 percent are found in the stomach ,
duodenum , or jejunum . [ 1 ] It usually appears as a smooth or umbilicated nodule. Rarely, pancreatic heterotopic tissue may be found in the colon , spleen or liver . [ 1 ]
The diagnosis of ectopic pancreas can be challenging. Confirmation of the diagnosis requires tissue sampling, via biopsy or surgical resection .
If no symptoms are present, then treatment is not necessary. When symptoms are present, treatment consists of surgical resection. [ 1 ]
The incidence of heterotopic pancreas is relatively low. [ 1 ]
This article related to pathology is a stub . You can help Wikipedia by expanding it .
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https://en.wikipedia.org/wiki/Ectopic_pancreas
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An ectopic tooth , also known as an impacted tooth , is a tooth that develops in an abnormal position ( ectopia ) and fails to erupt into its normal location in the oral cavity . [ 1 ] [ 2 ] Ectopic teeth can cause a variety of symptoms, such as pain, swelling, and infection, and they can lead to more serious complications if left untreated.
This condition can affect both deciduous teeth and permanent teeth , although it is more common in the permanent teeth. [ citation needed ]
Ectopic teeth may commonly occur within the dentate region of the jaws. Other common sites for ectopic teeth include the maxillary sinus , the nasal cavity , the mandibular condyle , and the palate . [ 3 ] The cause of ectopic teeth is not always clear, but it may be related to genetic factors or developmental abnormalities. [ 4 ]
Diagnosis of ectopic teeth typically involves a comprehensive dental examination, including X-rays and other imaging tests. Treatment options for ectopic teeth depend on the location and severity of the condition, as well as the age and overall health of the patient. In some cases, observation and monitoring may be sufficient, while in other cases, surgical intervention may be necessary to remove the ectopic tooth and prevent further complications. [ 5 ]
In addition to the physical symptoms, ectopic teeth can also have psychological and social impacts on affected individuals, particularly if the condition affects their appearance or causes them embarrassment or self-consciousness. As with any dental or medical condition, early diagnosis and treatment of ectopic teeth can help to prevent complications and improve outcomes for patients. [ 4 ]
The cause of developing an ectopic tooth is not yet exactly understood. However, they can result from trauma, infection, developmental anomalies such as cleft palate , pathologic conditions such as dentigerous cyst , iatrogenic or idiopathic factors. [ 6 ]
This dentistry article is a stub . You can help Wikipedia by expanding it .
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https://en.wikipedia.org/wiki/Ectopic_tooth
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Eczema vaccinatum is a rare severe adverse reaction to smallpox vaccination , caused by exposure to replicating live vaccinia virus.
It arises when vaccinia disseminates in people who have ever had atopic dermatitis or related eczematous disorders—or in their close contacts—because their impaired epidermal barrier permits unchecked viral spread. [ 1 ]
The condition may be fatal if severe and left untreated.
Older, replicating vaccinia vaccines like ACAM2000 or the historic Dryvax should not be given to patients with a history of eczema. Because of the danger of transmission of vaccinia , these also should not be given to people in close contact with anyone who has active eczema and who has not been vaccinated. People with other skin diseases (such as atopic dermatitis, burns , impetigo , or herpes zoster ) also have an increased risk of contracting eczema vaccinatum. Third-generation smallpox/monkeypox vaccines currently used in public health programmes do not contain live replicating vaccinia and are therefore not subject to this warning.
The incubation period from vaccinia exposure to rash averages 5–19 days. [ 2 ]
Eczema is also associated with increased complications related to other vesiculating viruses such as chickenpox ; this is called eczema herpeticum . [ citation needed ]
Experimental models show that Filaggrin deficiency—common in atopic dermatitis—facilitates systemic vaccinia spread, linking structural barrier genes to EV pathogenesis. [ 3 ]
EV is suspected when multiple vaccinia-type lesions arise outside the vaccination site in a patient with eczema or when such lesions follow close contact with a recent vaccinee. [ 4 ] Definitive confirmation relies on real-time PCR or culture to detect orthopoxvirus DNA from lesion material, differentiating EV from eczema herpeticum or bacterial impetigo. [ 5 ]
CDC surveillance criteria classify EV as a diffuse dermatological complication; confirmed cases must be reported through VAERS to facilitate a public-health response. [ 6 ]
Eczema vaccinatum is a serious medical condition that requires immediate and intensive medical care. Therapy has been supportive , such as antibiotics , fluid replacement , antipyretics and analgesics , skin healing, etc.; vaccinia immune globulin (VIG) could be very useful but supplies may be deficient as of 2006. Antiviral drugs have been examined for activity in pox viruses and cidofovir is believed to display potential in this area. [ 7 ] [ 8 ]
In March 2007, a two-year-old boy and his mother in Indiana contracted the life-threatening vaccinia infection from his father who was vaccinated against smallpox as part of the standard vaccination protocol for individuals serving in the US Armed Forces beginning in 2002. The child developed the pathognomonic rash which typifies eczema vaccinatum over 80 percent of his body surface area. The boy has a history of eczema, which is a known risk factor for vaccinia infection. [ 9 ]
Historical series place the overall case-fatality rate at 1–6 percent, rising to about 30 percent in infants under two years. [ 10 ]
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The Edinburgh College of Medicine for Women was established by The Scottish Association for the Medical Education of Women whose leading members included John Inglis , the father of Elsie Inglis . Elsie Inglis went on to become a leader in the suffrage movement and found the Scottish Women's Hospital organisation in World War I, but when the college was founded she was still a medical student. Her father, John Inglis, had been a senior civil servant in India, where he had championed the cause of education for women. On his return to Edinburgh he became a supporter of medical education for women and used his influence to help establish the college. The college was founded in 1889 at a time when women were not admitted to university medical schools in the UK, with the sole exception of London University. [ 1 ]
The college was set up as a result of a dispute within the Edinburgh School of Medicine for Women . This had been established in 1886 by Sophia Jex-Blake , who was regarded by many of her students as a strict disciplinarian. [ 2 ] When two students, Grace Cadell and her sister Martha, were dismissed in 1888 for a breach of rules, they successfully sued Jex-Blake and the school. Another student, Elsie Inglis , emerged as the leader of a group of students sympathetic to the Cadell sisters and increasingly hostile to Jex-Blake. [ 2 ] John Inglis her father had a circle of influential friends, including the Principal of the University of Edinburgh, Sir William Muir . They set up the Scottish Association for the Medical Education of Women , which soon had an impressive list of supporters and financial backers. [ 3 ] The first president was Sir Alexander Christison , who was striving to reverse the anti-female stance of his father Prof Robert Christison . [ 4 ]
The college opened in 1889. [ 3 ] The Association initially rented rooms at 30 Chambers Street [ 5 ] and in 1896 moved a few doors down to premises at Minto House, 20 Chambers Street, which had been the location of another private medical school and so was well suited to the needs of the college with lecture rooms and laboratories. [ 3 ] [ 5 ]
The college was set up in direct competition to Jex-Blake's Edinburgh School of Medicine for Women, which was to close in 1898. [ 6 ] [ 7 ] It aimed to prepare the women students for the examinations of the Triple Qualification (TQ) offered by the Scottish medical Royal Colleges. [ 6 ] Successful candidates were able to register with the General Medical Council and practice medicine in Britain, throughout much of the then British Empire and in some states of the United States of America. When the Scottish universities allowed women to graduate in medicine, many of the college's graduates were awarded the university degrees of MB, CM until 1899 or MB, ChB thereafter. [ 8 ]
In the first session the college had 18 lecturers whose lectures covered the syllabus of subjects required by the TQ. The TQ also required a series of clinical placements in a variety of specialities in approved hospitals. The main teaching hospital, the Royal Infirmary of Edinburgh , refused to allow women medical students on its wards. Jex-Blake's School of Medicine had arranged clinical teaching at a smaller teaching hospital Leith Hospital , and its wards were therefore not available to the college. The college arranged for its clinical teaching at Glasgow Royal Infirmary where two surgeons, Sir William Macewen and James Hogarth Pringle were ardent supporters of medical education for women. [ 9 ]
There was still much opposition to medical education for women and much of the success of the college resulted from the influential supporters of the Scottish Association for the Medical Education of Women. These included the Association's first president Sir Alexander Christison Bt, who ironically was the son of Sir Robert Christison who had been a leading opponent of medical education for women. Among the first Vice Presidents were Dr Robert Craig Maclagan and Sir Robert Philip the pioneer of tuberculosis treatment. [ 10 ]
In July 1892 the college had sufficient funds and sufficient influence to have two wards in the Royal Infirmary of Edinburgh opened to the women medical students of the college at a cost of £700. [ 11 ] The students were initially taught in the medical ward by Dr William Russell and Dr (later Sir) Byrom Bramwell and in the surgical ward by Mr (later Professor Sir) Joseph M Cotteril . [ 12 ]
The college closed in 1908 when its 20 Chambers Street buildings were sold. Thereafter the women students were taught in the School of Medicine of the Royal Colleges of Edinburgh until 1916. [ 6 ]
At the time of the college's foundation there was still opposition to medical education for women. By choosing to lecture at the college the lecturers were effectively making public their support for women in medicine. Most were young men several of whom would become well known in later life. [ 13 ] The first lecturers included:
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The Edinburgh Phrenological Society was founded in 1820 by George Combe , an Edinburgh lawyer, with his physician brother Andrew Combe . [ 1 ] The Edinburgh Society was the first and foremost phrenology grouping in Great Britain ; more than forty phrenological societies followed in other parts of the British Isles . The Society's influence was greatest over its first two decades and declined in the 1840s; the final meeting was recorded in 1870. [ 2 ]
The central concept of phrenology is that the brain is the organ of the mind and that human behaviour can be usefully understood in broadly neuropsychological rather than philosophical or religious terms. Phrenologists discounted supernatural explanations and stressed the modularity of mind . The Edinburgh phrenologists also acted as midwives to evolutionary theory and inspired a renewed interest in psychiatric disorder and its moral treatment . Phrenology claimed to be scientific but is now regarded as a pseudoscience as its formal procedures did not conform to the usual standards of scientific method. [ 3 ]
Edinburgh phrenologists included George and Andrew Combe; asylum doctor and reformer William A.F. Browne , father of James Crichton-Browne ; Robert Chambers , author of the 1844 proto-Darwinian book Vestiges of the Natural History of Creation ; William Ballantyne Hodgson , economist and pioneer of women's education; astronomer John Pringle Nichol ; and botanist and evolutionary thinker Hewett Cottrell Watson . Charles Darwin , a medical student in Edinburgh in 1825–7, took part in phrenological discussions at the Plinian Society and returned to Edinburgh in 1838 when formulating his concepts concerning natural selection . [ 4 ]
Phrenology emerged from the views of the medical doctor and scientific researcher Franz Joseph Gall in 18th-century Vienna. Gall suggested that facets of the mind corresponded to regions of the brain , and that it was possible to determine character traits by examining the shape of a person's skull. This "craniological" aspect was greatly extended by his one-time disciple, Johann Spurzheim , who coined the term phrenology and saw it as a means of advancing society by social reform (improving the material conditions of human life). [ 5 ] [ unreliable medical source? ]
In 1815, the Edinburgh Review published a hostile article by anatomist John Gordon, who called phrenology a "mixture of gross errors" and "extravagant absurdities". [ 6 ] In response, Spurzheim went to Edinburgh to take part in public debates and to perform brain dissections in public. Although he was received politely by the scientific and medical community there, many were troubled by the philosophical materialism implicit in phrenology. [ 7 ] George Combe, a lawyer who had previously been skeptical, became a convert to phrenology after listening to Spurzheim's commentary as he dissected a human brain. [ 8 ]
"Mental dispositions are determined by the size and constitution of the brain... and these are transmitted by hereditary descent..." George Combe The Constitution of Man in relation to External Objects (1828)
The Edinburgh Phrenological Society was founded on 22 February 1820, by the Combe brothers with the support of the Evangelical minister David Welsh . [ 9 ] The Society grew rapidly; in 1826, it had 120 members, an estimated one third of whom had a medical background. [ 10 ] The Society acquired large numbers of phrenological artefacts, such as marked porcelain heads indicating the location of cerebral organs, and endocranial casts of individuals with unusual personalities. Their museum was located on Chambers Street. [ 11 ]
Members published articles, gave lectures, and defended phrenology. Critics included philosopher Sir William Hamilton and the editor of the Edinburgh Review , Francis Jeffrey, Lord Jeffrey . [ 11 ] The hostility of other critics, including Alexander Monro tertius , anatomy professor at the University of Edinburgh Medical School , actually added to the glamour of phrenological concepts. Some anti-religionists, including the anatomist Robert Knox and the evolutionist Robert Edmond Grant , while sympathetic to its materialist implications, rejected the unscientific nature of phrenology and did not embrace its speculative and reformist aspects.
In 1823, Andrew Combe addressed the Royal Medical Society in a debate, arguing that phrenology explained the intellectual and moral abilities of mankind. [ 12 ] Both sides claimed victory after the lengthy debate, but the Medical Society refused to publish an account. [ 12 ] This prompted the Edinburgh Phrenological Society to establish its own journal in 1824: The Phrenological Journal and Miscellany , later renamed Phrenological Journal and Magazine of Moral Science . [ 13 ]
In the mid-1820s, a split emerged between the Christian phrenologists and Combe's closer associates. Matters came to a head when Combe and his supporters passed a motion banning the discussion of theology in the Society, effectively silencing their critics. In response, David Welsh and other evangelical members left the Society. [ 14 ]
In December 1826, the atheistic phrenologist William A.F. Browne caused a sensation at the university's Plinian Society with an attack on the recently republished theories of Charles Bell concerning the expression of the human emotions. Bell believed that human anatomy uniquely allowed the expression of the human moral self while Browne argued that there were no absolute distinctions between human and animal anatomy. Charles Darwin, then a 17-year-old student at the university, was there to listen. On 27 March 1827, Browne advanced phrenological theories concerning the human mind in terms of the Lamarckist evolution of the brain. This attracted the opposition of almost all members of the Plinian Society and, again, Darwin observed the ensuing outrage. [ 15 ] In his private notebooks, including the M Notebook written ten years later, Darwin commented sympathetically on the views of the phrenologists.
George Combe published The Constitution of Man in 1828. After a slow start, it became an international bestseller in the 19th century, with around 350,000 copies sold. [ 11 ] Almost a century later, psychiatrist Sir James Crichton-Browne said of the book: " The Constitution of Man on its first appearance was received in Edinburgh with an odium theologicum , analogous to that afterwards stirred up by the Vestiges of Creation and On The Origin of Species . It was denounced as an attack on faith and morals.... read today, it must be regarded as really rather more orthodox in its teaching than some of the lucubrations of the Dean of St Paul's and the Bishop of Durham". [ 16 ]
Phrenologists from the Society applied their methods to the Burke and Hare murders in Edinburgh. Over the course of ten months in 1828, Burke and Hare murdered sixteen people and sold the bodies for dissection in the private anatomy schools. Burke was executed on 28 January 1829, while Hare turned King's evidence; Burke was publicly dissected by Professor Monro the next day, and the phrenologists were permitted to examine his skull. Face masks of both men – a death-mask for Burke and a life-mask for Hare – form part of the Edinburgh phrenology collection.
Scotswoman Agnes Sillars Hamilton made a living as a "practical phrenologist", travelling throughout Britain and Ireland. Her son, Archibald Sillars Hamilton left for Australia in 1854, developed a successful phrenology practice there, and published an account of Ned Kelly 's skull. [ 17 ]
Society co-founder and president Andrew Combe had two successful publications in the early 1830s: Observations on Mental Derangement in 1831 and Physiology applied to Health and Education in 1834. [ 18 ] The latter, especially, sold well in Great Britain and the United States, with numerous editions and reprintings. [ 18 ]
The Edinburgh Phrenological Society received a financial boost by the death of a wealthy supporter in 1832. William Ramsay Henderson left a large bequest to the Edinburgh Society to promote phrenology as it saw fit. The Henderson Trust enabled the society to publish an inexpensive edition of The Constitution of Man , which went on to become one of the best-selling books of the 19th century. [ 11 ] [ 19 ] However, despite the widespread interest in phrenology in the 1820s and 1830s, the Phrenological Journal always struggled to make a profit.
"One is tempted to believe phrenologists are right about habitual exercise of the mind altering form of head, & thus these qualities become hereditary." Charles Darwin (1838) The M Notebook .
W.A.F. Browne : In 1832–1834, Browne published a paper in The Phrenological Journal in three serialised episodes On Morbid Manifestations of the Organ of Language, as connected with Insanity , relating mental disorder to a disturbance in the neurological organization of language . Browne went on to a distinguished career as an asylum doctor and his internationally influential 1837 publication What Asylums Were, Are and Ought To Be was dedicated to Andrew Combe. In 1866, after his twenty years of leadership at The Crichton asylum in Dumfries, Browne was elected President of the Medico-Psychological Association . In his later years, Browne returned to relationships of psychosis, brain injury and language in his 1872 paper Impairment of Language, The Result of Cerebral Disease , published in the West Riding Lunatic Asylum Medical Reports , edited by his son James Crichton-Browne.
Robert Chambers : Although not formally admitted to the Society, Chambers occasionally acted as George Combe's publisher and became an enthusiast for phrenological thinking. In 1844, Chambers anonymously published Vestiges of the Natural History of Creation , written as he recovered from depression at his holiday home in St Andrews . Chambers' wife, Anne Kirkwood, transcribed the manuscript for the publishers (dictated by her husband) so that they would not recognise its origins. In a strange parallel, Prince Albert read it aloud to Queen Victoria in the Summer of 1845. It became an international bestseller and a powerful public influence, situated midway between Combe's The Constitution of Man (1828) and Darwin's On the Origin of Species in 1859.
Charles Darwin : Darwin attended the University of Edinburgh Medical School and, as an active member of Plinian Society, [ 3 ] observed the 1826-1827 controversies with phrenologist William A.F. Browne. In 1838, some eleven years after his hurried departure, Darwin revisited Edinburgh and his undergraduate haunts, recording his psychological speculations in the M Notebook and teasing out the details of his theory of natural selection . At this time, Darwin was preparing for marriage with his religiously minded cousin Emma Wedgwood , and was in some emotional turmoil: on 21 September, after his return to England, he recorded a vivid and disturbing dream in which he seemed to be involved in an execution at which the corpse came to life and joked about having died as a hero. Darwin made his "gigantic blunder" concerning the parallel roads of Glen Roy while on this Scottish trip, suggesting an element of mental distraction. He published On the Origin of Species some twenty years later, in 1859; the book was translated into many languages, and became a staple scientific text and a key fixture of modern scientific culture.
William Ballantyne Hodgson : Hodgson joined the phrenology movement as a student at Edinburgh University and later supported himself as a professional lecturer on literature, education, and phrenology. He became an educational reformer, a pioneering proponent of women's education and – in 1871 – the first Professor of Political Economy (and Mercantile Law) at Edinburgh University. In later life, Hodgson lived at Bonaly Tower outside Edinburgh, and was elected President of the Educational Institute of Scotland .
Thomas Laycock : Laycock was one of George Combe's "influential disciples". [ 20 ] He was a pioneering neurophysiologist . In 1855, Laycock was appointed to the Chair of Medicine in Edinburgh University. In 1860, Laycock published his Mind and Brain , an extended essay on the neurological foundations of psychological life. Laycock was friendly with asylum reformer William A.F. Browne and was an important influence on Browne's son, Sir James Crichton-Browne.
John Pringle Nichol : Nichol was originally educated and licensed as a preacher , but the impact of phrenological thinking pushed him into education. [ 21 ] He became a celebrated lecturer and Regius Professor of Astronomy in Glasgow University, and his 1837 book The Architecture of the Heavens was a classic of popular science. In the 1840s, Nichol became addicted to prescription opiates, and he recorded his successful hydropathic rehabilitation in his autobiographical correspondence Memorials from Ben Rhydding .
Hewett Cottrell Watson : In 1836, Watson published a paper in The Phrenological Journal entitled What Is The Use of the Double Brain? in which he speculated on the differential development of the two human cerebral hemispheres . This theme of cerebral asymmetry was picked up rather casually by the London society physician Sir Henry Holland in 1840, and then much more extensively by the eccentric Brighton medical practitioner Arthur Ladbroke Wigan in his 1844 treatise A New View of Insanity: On the Duality of Mind . [ 22 ] It did not achieve scientific status until Paul Broca , encouraged by the French phrenologist/physician Jean-Baptiste Bouillaud , published his research into the speech centres of the brain in 1861. In 1868, Broca presented his findings at the Norwich meeting of the British Association for the Advancement of Science . In 1889, Henry Maudsley published a searching review of this topic entitled The Double Brain in the philosophical journal Mind . [ 23 ] Like Robert Chambers, Watson later turned his energies to the question of the transmutation of species , and, having bought the Phrenological Journal with the proceeds of a large inheritance, appointed himself as its editor in 1837. In the 1850s, Watson conducted an extensive correspondence with Charles Darwin concerning the geographical distribution of British plant species, and Darwin made generous acknowledgement of Watson's scientific assistance in On The Origin of Species (second edition). Watson was unusual amongst phrenologists in explicitly disavowing phrenological ideas in later life.
Interest in phrenology declined in Edinburgh in the 1840s. Some of the phrenologists' concerns drifted into the related fields of anthropometry , psychiatry and criminology , and also into degeneration theory as set out by Bénédict Morel , Arthur de Gobineau and Cesare Lombroso . [ 24 ] In the 1870s, the eminent social psychologist Gustav Le Bon (1841–1931) invented a cephalometer which facilitated the measurement of cranial capacity and variation. In 1885, the German medical scientist Rudolf Virchow launched a large scale craniometric investigation of the supposed racial stereotypes with decisively negative results for the proponents of racial science . Worldwide, interest in phrenology remained high throughout the nineteenth century, with George Combe's The Constitution of Man being much in demand. Combe devoted his later years to international travel, lecturing on phrenology. He was preparing the ninth edition of The Constitution of Man when he died while receiving hydrotherapy treatment at Moor Park, Farnham .
The last recorded meeting of the Society took place in 1870. [ 25 ] The Society's museum closed in 1886. [ 11 ]
"You interest me very much, Mr Holmes. I had hardly expected so dolicocephalic a skull or such well marked supra-orbital development.... A cast of your skull, sir, until the original is available, would be an ornament to any anthropological museum..." – Arthur Conan Doyle The Hound of the Baskervilles (1902).
Together with mesmerism , [ 26 ] phrenology exerted an extraordinary influence on the Victorian literary imagination in the later 19th century, especially in the fin-de-siècle aesthetic, and comparable to the later cultural influences of spiritualism and psychoanalysis . Examples of phrenology's literary legacy feature in the works of Sir Arthur Conan Doyle , George du Maurier , Bram Stoker , Robert Louis Stevenson and H. G. Wells .
On 29 February 1924, Sir James Crichton-Browne (the son of William A.F. Browne) delivered the Ramsay Henderson Bequest Lecture entitled The Story of the Brain in which he recorded a generous appreciation of the role of the Edinburgh phrenologists in the later development of neurology and neuropsychiatry . Crichton-Browne did not remark, however, on his father's having joined the Society a century earlier, almost to the day.
"While defending the fundamental principle that the brain is the organ of the mind.... the phrenologists were exposed to violent abuse, ridicule and vituperation.... it was, of course, their craniological conclusions, their dissection of the mind into a number of component faculties.... that was the main point of attack, and that, it must be allowed, readily leant itself to burlesque...." James Crichton-Browne (1924) The Story of The Brain.
The Henderson Trust was wound up in 2012. [ 27 ] Many of the society's phrenological artefacts survive today, having passed to the University of Edinburgh's Anatomical Museum [ 27 ] under the direction of Professor Matthew Kaufman , and some are now on display at the Scottish National Portrait Gallery .
The activities of the Edinburgh phrenologists have enjoyed an unusual afterlife in the history and sociology of scientific knowledge ( science studies ), as an example of a discarded cultural production.
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Personalized medicine involves medical treatments based on the characteristics of individual patients, including their medical history , family history , and genetics . Although personal genetic information is becoming increasingly important in healthcare, there is a lack of sufficient education in medical genetics among physicians and the general public. [ 1 ] [ 2 ] [ 3 ] For example, pharmacogenomics (genetic factors influencing drug response) is practiced worldwide by only a limited number of pharmacists, although most pharmacy colleges in the United States now include it in their curriculum. [ 3 ] It is also increasingly common for genetic testing to be offered directly to consumers, who subsequently seek out educational materials and bring their results to their doctors. [ 1 ] Issues involving genetic testing also invariably lead to ethical and legal concerns, such as the potential for inadvertent effects on family members, increased insurance rates, or increased psychological stress. [ 4 ] [ 5 ]
As of 2009, the primary of the care physicians did not have adequate training in genetics or genomics . [ 2 ] Although medical school curricula typically include medical genetics, fewer than half offer a standalone course, and the emphasis on practical applications is weak. [ 1 ] [ 2 ] [ 6 ]
In the United States, Stanford University was the first medical school in the United States to offer a course teaching the interpretation of genetic data. [ 7 ] Students were able to study their own genotypes , determined using commercially available genotyping platforms ( 23andMe or Navigenics ). [ 8 ] Although there was skepticism that this would improve educational outcomes, [ 8 ] a survey later showed that this had increased students’ enthusiasm for the subject. [ 9 ] A similar class is offered at Mount Sinai School of Medicine , launched in 2012, in which students have the option of analyzing their entire genome sequence instead of only their genotype. [ 10 ] [ 11 ]
In 2010, the University of California, Berkeley offered entering students a genetic test for SNPs affecting alcohol, lactose, and folate metabolism. [ 12 ] [ 13 ] The goal was “to spark discussion during orientation on how genetic testing works, the results of the students' tests and their decisions on whether or not to participate.” [ 8 ] However, criticism of the program led to an informational hearing by the California State Committee on Higher Education, and a bill was introduced by Chris Norby to prevent California state universities from genetically testing their students. [ 14 ] [ 15 ] The California Department of Public Health concluded that the program constituted clinical testing, and the university released only aggregate information instead of personal results. [ 16 ] [ 17 ]
As described in the preceding section, in some courses on personalized medicine, students have been able to study their personal genetic information. For the Stanford course, which was designed for graduate and medical students, a review was conducted in 2009-2010 by a “joint genotyping task force” including research and clinical faculty, biomedical ethicists, genetic counselors, and legal counsel. [ 4 ] [ 12 ] The recommendations adopted included: making genetic testing optional (with instructors blinded to the choice of the students), strict data confidentiality (only aggregate data was made available during discussions), incorporation of lectures discussing issues related to personal genotyping, and availability of genetic counseling to students if necessary. [ 4 ]
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According to the US Department of Education , the Educational Commission for Foreign Medical Graduates ( ECFMG ) is "the authorized credential evaluation and guidance agency for non-U.S. physicians and graduates of non-U.S. medical schools who seek to practice in the United States or apply for a U.S. medical residency program. It provides comprehensive information and resources on licensure, the U.S. Medical Licensure Examination (USMLE), residencies, and recognition." [ 1 ]
Through its program of certification , the ECFMG assesses the readiness of international medical graduates to enter residency or fellowship programs in the United States that are accredited by the Accreditation Council for Graduate Medical Education (ACGME).
ECFMG acts as the registration and score-reporting agency for the USMLE for foreign medical students/ graduates, or in short, it acts as the designated Dean's office for International Medical Graduates (IMGs) in contrast to the American Medical Graduates (AMGs).
Medical schools in Canada that award the M.D. are not assessed by ECFMG, because the Liaison Committee on Medical Education historically accredited M.D.-granting institutions in both the U.S. and Canada (today, Canada has its own accrediting body that generally follows U.S. standards). M.D. graduates of American and Canadian institutions are not considered IMGs in either country.
ECFMG was founded in 1956, in response to the increase need for the evaluation of the readiness of international medical graduates entering the physician workforce during the 1950 expansion of US healthcare system. Its initial name was Evaluation Service for Foreign Medical Graduates (ESFMG). [ 2 ] Later that year, it was renamed Educational Council for Foreign Medical Graduates. In conjunction with NBME ,
it created what became known as the ECFMG certification which included examinations and
assessments of English language proficiency. [ citation needed ] In 1974, it merged with the Commission on Foreign Medical Graduates and changed its name
to its current name Educational Commission for Foreign Medical Graduates. [ 3 ]
The main pathway for international medical graduates who wish to be licensed as a physician in the United States is to complete a U.S. residency hospital program. The general method to apply for residency programs is through the National Resident Matching Program (abbreviated NRMP, but also called "the Match"). To participate in the NRMP, an IMG is required to have an ECFMG certification [ 4 ] by the "rank order list certification deadline" time (usually in February of the year of the match). [ 5 ]
To acquire an ECFMG certification, the candidate must meet these requirements: [ 6 ]
In comparison, regular graduates from medical schools in the United States need to complete USMLE Steps 1 and 2 as well, but can participate in the NRMP while still doing their final year of medical school before acquiring their medical diplomas. [ 8 ] In effect, taking regular administrative delays into account, and with residency programs starting around July, there is a gap of at least half a year for IMGs between graduation from medical school and beginning of a residency program.
The COVID-19 global pandemic has brought some changes to the ECFMG certification process. First as AAMC suspended temporarily and later eliminated the Step 2 CS examination, [ 9 ] ECFMG moved to a pathways model for verification of clinical skills. [ 10 ] IMGs who have already taken Step 2 CS may still use it to fulfill this requirement. All other IMGs will need:
As of April 2021, ECFMG certifications obtained by fulfilling the clinical and communication skills requirements through a pathway will expire in 2022 if the applicant does not enter an ACGME-accredited training program in 2021 or 2022. If the applicant enters a training program they become permanent after one year of residency. [ 7 ]
A pilot project was started in 2012 for an electronic verification system of medical credentials from international medical schools, with participation from approximately 20 international medical schools. [ 11 ] After completion of this pilot project, ECFMG now allows all medical schools to register for free. [ 12 ]
Expected to be implemented in late 2024, a notable development is anticipated in medical education application procedures. ECFMG Status Reports will be integrated into Electronic Residency Application Service (ERAS) submissions, offering vital information for institutions assessing applicants. These reports will specifically indicate whether the candidate's medical school meets the Recognized Accreditation Policy, determined by accreditation from agencies recognized by the World Federation for Medical Education or the National Committee on Foreign Medical Education and Accreditation. This enhancement aims to streamline the evaluation of medical school credentials, enhancing transparency and efficiency in the residency application process. However, IMGs will still be able to pursue ECFMG Certification even if their medical school doesn't meet the Recognized Accreditation Policy, as long as their school meets ECFMG's current requirements. [ 13 ] The accrediting agencies that are WFME recognized are:
July 2033
International medical schools can send Medical Student Performance Evaluations (MSPEs) and medical school transcripts on behalf of their students and graduates to ECFMG through digital documents by the ECFMG Medical School Web Portal (EMSWP) [ 15 ]
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https://en.wikipedia.org/wiki/Educational_Commission_for_Foreign_Medical_Graduates
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The Edwin Grant Conklin Medal was inaugurated in 1995 by the Society for Developmental Biology in honor of the biologist Edwin Conklin . It is awarded annually to recognise a member of the society who has carried out distinguished and sustained research in developmental biology. The recipient delivers a feature lecture at the annual society meeting and is presented with a commemorative plaque. [ 1 ]
The following have won the award: [ 1 ]
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The Edwin Smith Papyrus is an ancient Egyptian medical text , named after Edwin Smith who bought it in 1862, and the oldest known surgical treatise [ 2 ] on trauma .
This document, which may have been a manual of military surgery, describes 48 cases of injuries, fractures, wounds, dislocations and tumors. [ 3 ] It dates to Dynasties 16 – 17 of the Second Intermediate Period in ancient Egypt, c. 1600 BCE. [ 4 ] : 70 The papyrus is unique among the four principal medical papyri [ 5 ] that survive today. While other papyri, such as the Ebers Papyrus and London Medical Papyrus , are medical texts based in magic , the Edwin Smith Papyrus presents a rational and scientific approach to medicine in ancient Egypt, [ 6 ] : 58 in which medicine and magic do not conflict. Magic would be more prevalent had the cases of illness been mysterious, such as internal disease. [ 7 ]
The Edwin Smith papyrus is a scroll 4.68 meters or 15.3 feet in length. The recto (front side) has 377 lines in 17 columns, while the verso (backside) has 92 lines in five columns. Aside from the fragmentary outer column of the scroll, the remainder of the papyrus is intact, although it was cut into one-column pages some time in the 20th century. [ 4 ] : 70 It is written right-to-left in hieratic , the Egyptian cursive form of hieroglyphs , in black ink with explanatory glosses in red ink . The vast majority of the papyrus is concerned with trauma and surgery, with short sections on gynaecology and cosmetics on the verso. [ 8 ] On the recto side, there are 48 cases of injury. Each case details the type of the injury, examination of the patient, diagnosis and prognosis, and treatment. [ 9 ] : 26–28 The verso side consists of eight magic spells and five prescriptions. The spells of the verso side and two incidents in Case 8 and Case 9 are the exceptions to the practical nature of this medical text. [ 4 ] : 70 Generic spells and incantations may have been used as a last resort in terminal cases. [ 7 ]
Authorship of the Edwin Smith Papyrus is debated. The majority of the papyrus was written by one scribe, with only small sections copied by a second scribe. [ 7 ] The papyrus ends abruptly in the middle of a line, without any inclusion of an author. [ 4 ] : 71 It is believed that the papyrus is an incomplete copy of an older reference manuscript from the Old Kingdom, evidenced by archaic grammar, terminology, [ 8 ] form and commentary. James Henry Breasted speculates - but emphasises that this is pure conjecture based on no evidence - that the original author might be Imhotep , an architect, high priest, and physician of the Old Kingdom, 3000–2500 BCE. [ 10 ] : 9
The rational and practical nature of the papyrus is illustrated in 48 case histories, which are listed according to each organ. [ 5 ] Presented cases are typical, not individual. [ 2 ] The papyrus begins by addressing injuries to the head, and continues with treatments for injuries to neck, arms and torso, [ 9 ] : 29 detailing injuries in descending anatomical order [ 8 ] like a modern anatomical exposition. [ 2 ] The title of each case details the nature of trauma, such as "Practices for a gaping wound in his head, which has penetrated to the bone and split the skull". [ 4 ] : 74 The objective examination process [ 11 ] included visual and olfactory clues, palpation and taking of the pulse. [ 8 ] Following the examination are the diagnosis and prognosis, where the physician judges the patient’s chances of survival and makes one of three diagnoses: "An ailment which I will treat," "An ailment with which I will contend," or "An ailment not to be treated". [ 8 ] Last, treatment options are offered. In many of the cases, explanations of trauma are included to provide further clarity. [ 4 ] : 70
Among the treatments are closing wounds with sutures (for wounds of the lip, throat, and shoulder), [ 12 ] bandaging, splints, poultices , [ 8 ] preventing and curing infection with honey, and stopping bleeding with raw meat. [ 4 ] : 72 Immobilization is advised for head and spinal cord injuries, as well as other lower body fractures. The papyrus also describes realistic anatomical , physiological and pathological observations. [ 11 ] It contains the first known descriptions of the cranial structures, the meninges , the external surface of the brain, the cerebrospinal fluid , and the intracranial pulsations. [ 2 ] : 1 The procedures of this papyrus demonstrate an Egyptian level of knowledge of medicines that surpassed that of Hippocrates , who lived 1000 years later, [ 6 ] : 59 and the documented rationale for diagnosis and treatment of spinal injuries can still be regarded as the state-of-the-art reasoning for modern clinical practice. [ 13 ] The influence of brain injuries on parts of the body is recognized, such as paralysis . The relationship between the location of a cranial injury and the side of the body affected is also recorded, while crushing injuries of vertebrae were noted to impair motor and sensory functions. [ 11 ] Due to its practical nature and the types of trauma investigated, it is believed that the papyrus served as a textbook for the trauma that resulted from military battles. [ 4 ] : 11
The Edwin Smith Papyrus dates to Dynasties 16–17 of the Second Intermediate Period . Egypt was ruled from Thebes during this time and the papyrus is likely to have originated from there. [ 4 ] : 70–71 Edwin Smith , an American Egyptologist, purchased it in Luxor , Egypt in 1862, from an Egyptian dealer named Mustafa Agha. [ 9 ] : 25
The papyrus was in the possession of Smith until his death, when his daughter donated the papyrus to New York Historical Society . There its importance was recognized by Caroline Ransom Williams , who wrote to James Henry Breasted in 1920 about "the medical papyrus of the Smith collection" in hopes that he could work on it. [ 14 ] [ 15 ] He completed the first translation of the papyrus in 1930, with the medical advice of Dr. Arno B. Luckhardt . [ 9 ] : 26 Breasted’s translation changed the understanding of the history of medicine. It demonstrates that Egyptian medical care was not limited to the magical modes of healing demonstrated in other Egyptian medical sources. Rational, scientific practices were used, constructed through observation and examination. [ 10 ] : 12
From 1938 through 1948, the papyrus was at the Brooklyn Museum . In 1948, the New York Historical Society and the Brooklyn Museum presented the papyrus to the New York Academy of Medicine , where it remains today. [ 4 ] : 70
From 2005 through 2006, the Edwin Smith Papyrus was on exhibition at the Metropolitan Museum of Art in New York. James P. Allen , curator of Egyptian Art at the museum, published a new translation of the work, coincident with the exhibition. [ 4 ] This was the first complete English translation since Breasted’s in 1930. This translation offers a more modern understanding of hieratic and medicine.
As listed in [ 16 ]
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Effacement is the shortening, or thinning, of a tissue .
It can refer to cervical effacement . It can also refer to a process occurring in podocytes in nephrotic syndrome . [ 1 ]
In histopathology , it refers to the near obliteration of a tissue, as in the normal parenchyma of tissues in the case of some cancers.
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In electrocardiography , during a cardiac cycle , once an action potential is initiated, there is a period of time that a new action potential cannot be initiated. This is termed the effective refractory period (ERP) of the tissue. This period is approximately equal to the absolute refractory period (ARP), it occurs because the fast sodium channels remain closed until the cell fully repolarizes. [ 1 ] During this period, depolarization on adjacent cardiac muscles does not produce a new depolarization in the current cell as it has to refract back to phase 4 of the action potential before a new action potential can activate it. ERP acts as a protective mechanism and keeps the heart rate in check and prevents arrhythmias , and it helps coordinates muscle contraction. Anti-arrhythmic agents used for arrhythmias usually prolong the ERP. For the treatment of atrial fibrillation , it is a problem that the prolongation of the ERP by these agents also affects the ventricles, which can induce other types of arrhythmias. [ 2 ]
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The effects of long-term benzodiazepine use include drug dependence as well as the possibility of adverse effects on cognitive function, physical health, and mental health. [ 1 ] Long-term use is sometimes described as use not shorter than three months. [ 2 ] Benzodiazepines are generally effective when used therapeutically in the short term, [ 3 ] but even then the risk of dependency can be significantly high. There are significant physical, mental and social risks associated with the long-term use of benzodiazepines . [ 3 ] Although anxiety can temporarily increase as a withdrawal symptom, there is evidence that a reduction or withdrawal from benzodiazepines can lead to a reduction of anxiety symptoms in the long run. [ 4 ] [ 5 ] Due to these increasing physical and mental symptoms from long-term use of benzodiazepines, slow withdrawal is recommended for long-term users. [ 6 ] [ 7 ] [ 8 ] [ 9 ] Not everyone, however, experiences problems with long-term use. [ 10 ]
Some of the symptoms that could possibly occur as a result of a withdrawal from benzodiazepines after long-term use include emotional clouding, [ 1 ] flu-like symptoms, [ 5 ] suicide , [ 11 ] nausea , headaches , dizziness , irritability , lethargy , sleep problems, memory impairment , personality changes, aggression , depression , social deterioration as well as employment difficulties, while others never have any side effects from long-term benzodiazepine use. Abruptly or rapidly stopping benzodiazepines can be dangerous; when withdrawing, a gradual reduction in dosage is recommended, under professional supervision. [ 7 ] [ 12 ] [ 9 ]
While benzodiazepines are highly effective in the short term, adverse effects associated with long-term use, including impaired cognitive abilities, memory problems, mood swings, and overdoses when combined with other drugs, may make the risk-benefit ratio unfavourable. In addition, benzodiazepines have reinforcing properties in some individuals and thus are considered to be addictive drugs, especially in individuals that have a "drug-seeking" behavior; further, a physical dependence can develop after a few weeks or months of use. [ 13 ] Many of these adverse effects associated with long-term use of benzodiazepines begin to show improvements three to six months after withdrawal. [ 14 ] [ 15 ]
Other concerns about the effects associated with long-term benzodiazepine use, in some, include dose escalation, benzodiazepine use disorder , tolerance and benzodiazepine dependence and benzodiazepine withdrawal problems. Both physiological tolerance and dependence can be associated with worsening the adverse effects associated with benzodiazepines. Increased risk of death has been associated with long-term use of benzodiazepines in several studies; however, other studies have not found increased mortality . Due to conflicting findings in studies regarding benzodiazepines and increased risks of death including from cancer, further research in long-term use of benzodiazepines and mortality risk has been recommended; most of the available research has been conducted in prescribed users, even less is known about illicit misusers. [ 16 ] [ 17 ] The long-term use of benzodiazepines is controversial and has generated significant debate within the medical profession. Views on the nature and severity of problems with long-term use of benzodiazepines differ from expert to expert and even from country to country; some experts even question whether there is any problem with the long-term use of benzodiazepines. [ 18 ]
Effects of long-term benzodiazepine use may include disinhibition , impaired concentration and memory, depression , [ 19 ] [ 20 ] as well as sexual dysfunction . [ 6 ] [ 21 ] The long-term effects of benzodiazepines may differ from the adverse effects seen after acute administration of benzodiazepines. [ 22 ] An analysis of cancer patients found that those who took tranquillisers or sleeping tablets had a substantially poorer quality of life on all measurements conducted, as well as a worse clinical picture of symptomatology. Worsening of symptoms such as fatigue , insomnia , pain , dyspnea and constipation was found when compared against those who did not take tranquillisers or sleeping tablets. [ 23 ] Most individuals who successfully discontinue hypnotic therapy after a gradual taper and do not take benzodiazepines for 6 months have less severe sleep and anxiety problems, are less distressed and have a general feeling of improved health at 6-month follow-up. [ 15 ] The use of benzodiazepines for the treatment of anxiety has been found to lead to a significant increase in healthcare costs due to accidents and other adverse effects associated with the long-term use of benzodiazepines. [ 24 ]
Long-term benzodiazepine use can lead to a generalised impairment of cognition , including sustained attention, verbal learning and memory and psychomotor , visuo-motor and visuo-conceptual abilities. [ 25 ] [ 26 ] Transient changes in the brain have been found using neuroimaging studies, but no brain abnormalities have been found in patients treated long term with benzodiazepines. [ 27 ] When benzodiazepine users cease long-term benzodiazepine therapy, their cognitive function improves in the first six months, although deficits may be permanent or take longer than six months to return to baseline. [ 28 ] In the elderly, long-term benzodiazepine therapy is a risk factor for amplifying cognitive decline, [ 29 ] although gradual withdrawal is associated with improved cognitive status. [ 30 ] A study of alprazolam found that 8 weeks administration of alprazolam resulted in deficits that were detectable after several weeks but not after 3.5 years. [ 31 ]
Sleep can be adversely affected by benzodiazepine dependence. Possible adverse effects on sleep include induction or worsening of sleep disordered breathing. Like alcohol , benzodiazepines are commonly used to treat insomnia in the short term (both prescribed and self-medicated), but worsen sleep in the long term. Although benzodiazepines can put people to sleep, while asleep, the drugs disrupt sleep architecture, decreasing sleep time, delayed and decreased REM sleep, increased alpha and beta activity, decreased K complexes and delta activity, and decreased deep slow-wave sleep (i.e., NREM stages 3 and 4, the most restorative part of sleep for both energy and mood). [ 32 ] [ 33 ] [ 34 ]
The long-term use of benzodiazepines may have a similar effect on the brain as alcohol , and is also implicated in depression , anxiety , post-traumatic stress disorder (PTSD), mania, psychosis, sleep disorders , sexual dysfunction, delirium, and neurocognitive disorders. [ 35 ] [ 36 ] However a 2016 study found no association between long-term usage and dementia. [ 37 ] As with alcohol, the effects of benzodiazepine on neurochemistry, such as decreased levels of serotonin and norepinephrine , are believed to be responsible for their effects on mood and anxiety. [ 38 ] [ 39 ] [ 40 ] [ 41 ] [ 42 ] [ 43 ] Additionally, benzodiazepines can indirectly cause or worsen other psychiatric symptoms (e.g., mood, anxiety, psychosis, irritability) by worsening sleep (i.e., benzodiazepine-induced sleep disorder). These effects are paradoxical to the use of benzodiazepines, both clinically and non-medically , in management of mental health conditions. [ 44 ] [ 45 ]
Long-term benzodiazepine use may lead to the creation or exacerbation of physical and mental health conditions, which improve after six or more months of abstinence. After a period of about 3 to 6 months of abstinence after completion of a gradual-reduction regimen, marked improvements in mental and physical wellbeing become apparent. For example, one study of hypnotic users gradually withdrawn from their hypnotic medication reported after six months of abstinence that they had less severe sleep and anxiety problems, were less distressed, and had a general feeling of improved health. Those who remained on hypnotic medication had no improvements in their insomnia, anxiety, or general health ratings. [ 15 ] A study found that individuals having withdrawn from benzodiazepines showed a marked reduction in use of medical and mental health services. [ 46 ] [ non-primary source needed ]
Approximately half of patients attending mental health services for conditions including anxiety disorders such as panic disorder or social phobia may be the result of alcohol or benzodiazepine dependence. [ 47 ] Sometimes anxiety disorders precede alcohol or benzodiazepine dependence but the alcohol or benzodiazepine dependence often acts to keep the anxiety disorders going and often progressively makes them worse. [ 47 ] [ non-primary source needed ] Many people who are addicted to alcohol or prescribed benzodiazepines decide to quit when it is explained to them they have a choice between ongoing ill mental health or quitting and recovering from their symptoms. It was noted that because every individual has an individual sensitivity level to alcohol or sedative hypnotic drugs, what one person can tolerate without ill health will cause another to develop very ill health, and that even moderate drinking in sensitive individuals can cause rebound anxiety syndromes and sleep disorders. A person who experiences the toxic effects of alcohol or benzodiazepines will not benefit from other therapies or medications as they do not address the root cause of the symptoms. [ 47 ] Recovery from benzodiazepine dependence tends to take a lot longer than recovery from alcohol, [ 47 ] [ 48 ] but people can regain their previous good health. [ 47 ] [ medical citation needed ] A review of the literature regarding benzodiazepine hypnotic drugs concluded that these drugs cause an unjustifiable risk to the individual and to public health. The risks include dependence , accidents and other adverse effects. Gradual discontinuation of hypnotics leads to improved health without worsening of sleep. [ 49 ]
Daily users of benzodiazepines are also at a higher risk of experiencing psychotic symptomatology such as delusions and hallucinations . [ 50 ] A study found that of 42 patients treated with alprazolam, up to a third of long-term users of the benzodiazepine drug alprazolam ( Xanax ) develop depression . [ 40 ] Studies have shown that long-term use of benzodiazepines and the benzodiazepine receptor agonist nonbenzodiazepine Z drugs are associated with causing depression as well as a markedly raised suicide risk and an overall increased mortality risk. [ 41 ] [ 51 ]
A study of 50 patients who attended a benzodiazepine withdrawal clinic found that, after several years of chronic benzodiazepine use, a large portion of patients developed health problems including agoraphobia , irritable bowel syndrome , paraesthesiae , increasing anxiety, and panic attacks , which were not preexisting. The mental health and physical health symptoms induced by long-term benzodiazepine use gradually improved significantly over a period of a year following completion of a slow withdrawal. Three of the 50 patients had wrongly been given a preliminary diagnosis of multiple sclerosis when the symptoms were actually due to chronic benzodiazepine use. Ten of the patients had taken drug overdoses whilst on benzodiazepines, despite the fact that only two of the patients had any prior history of depressive symptomatology. After withdrawal, no patients took any further overdoses after one year post-withdrawal. The cause of the deteriorating mental and physical health in a significant proportion of patients was hypothesised to be caused by increasing tolerance where withdrawal-type symptoms emerged, despite the administration of stable prescribed doses. [ 52 ] Another theory is that chronic benzodiazepine use causes subtle increasing toxicity, which in turn leads to increasing psychopathology in long-term users of benzodiazepines. [ 53 ]
Long-term use of benzodiazepines can induce perceptual disturbances and depersonalization in some people, even in those taking a stable daily dosage, and it can also become a protracted withdrawal feature of the benzodiazepine withdrawal syndrome . [ 54 ]
In addition, chronic use of benzodiazepines is a risk factor for blepharospasm . [ 55 ] Drug-induced symptoms that resemble withdrawal-like effects can occur on a set dosage as a result of prolonged use, also documented with barbiturate -like substances, as well as alcohol and benzodiazepines . This demonstrates that the effects from chronic use of benzodiazepine drugs are not unique but occur with other GABAergic sedative hypnotic drugs, i.e., alcohol and barbiturates. [ 56 ]
Chronic use of benzodiazepines seemed to cause significant immunological disorders in a study of selected outpatients attending a psychopharmacology department. [ 57 ] Diazepam and clonazepam have been found to have long-lasting, but not permanent, immunotoxic effects in fetuses of rats. However, single very high doses of diazepam have been found to cause lifelong immunosuppression in neonatal rats. No studies have been done to assess the immunotoxic effects of diazepam in humans; however, high prescribed doses of diazepam, in humans, have been found to be a major risk of pneumonia, based on a study of people with tetanus. It has been proposed that diazepam may cause long-lasting changes to the GABA A receptors with resultant long-lasting disturbances to behaviour, endocrine function and immune function. [ 58 ]
Use of prescribed benzodiazepines is associated with an increased rate of suicide or attempted suicide . The prosuicidal effects of benzodiazepines are suspected to be due to a psychiatric disturbance caused by side effects or withdrawal symptoms. [ 11 ] Because benzodiazepines in general may be associated with increased suicide risk, care should be taken when prescribing, especially to at-risk patients. [ 59 ] [ 60 ] Depressed adolescents who were taking benzodiazepines were found to have a greatly increased risk of self-harm or suicide , although the sample size was small. The effects of benzodiazepines in individuals under the age of 18 requires further research. Additional caution is required in using benzodiazepines in depressed adolescents. [ 61 ] Benzodiazepine dependence often results in an increasingly deteriorating clinical picture, which includes social deterioration leading to comorbid alcohol use disorder and substance use disorder . Benzodiazepine misuse or misuse of other CNS depressants increases the risk of suicide in drug misusers. [ 62 ] [ 63 ] Benzodiazepine has several risks based on its biochemical function and symptoms associated with this medication like exacerbation of sleep apnea, sedation, suppression of self-care functions, amnesia and disinhibition are suggested as a possible explanation to the increase in mortality. Studies also demonstrate that an increased mortality associated with benzodiazepine use has been clearly documented among 'drug misusers'. [ 17 ]
There has been some controversy around the possible link between benzodiazepine use and development of cancer; early cohort studies in the 1980s suggested a possible link, but follow-up case-control studies have found no link between benzodiazepines and cancer. In the second U.S. national cancer study in 1982, the American Cancer Society conducted a survey of over 1.1 million participants. A markedly increased risk of cancer was found in users of sleeping pills, mainly benzodiazepines. [ 64 ] Fifteen epidemiologic studies have suggested that benzodiazepine or nonbenzodiazepine hypnotic drug use is associated with increased mortality , mainly due to increased cancer death. The cancers included cancer of the brain , lung , bowel , breast , and bladder , and other neoplasms . It has been hypothesised [ by whom? ] that benzodiazepines depress immune function and increase viral infections and could be the cause or trigger of the increased rate of cancer. While initially U.S. Food and Drug Administration reviewers expressed concerns about approving the nonbenzodiazepine Z drugs due to concerns of cancer, ultimately they changed their minds and approved the drugs. [ 65 ] A 2017 meta-analysis of multiple observational studies found that benzodiazepine use is associated with increased cancer risk. [ 66 ]
In a study in 1980 in a group of 55 consecutively admitted patients having engaged in non-medical use of exclusively sedatives or hypnotics, neuropsychological performance was significantly lower and signs of intellectual impairment significantly more often diagnosed than in a matched control group taken from the general population. These results suggested a relationship between non-medical use of sedatives or hypnotics and cerebral disorder. [ 67 ]
A publication asked in 1981 if lorazepam is more toxic than diazepam . [ 68 ]
In a study in 1984, 20 patients having taken long-term benzodiazepines were submitted to brain CT scan examinations. Some scans appeared abnormal. The mean ventricular-brain ratio measured by planimetry was increased over mean values in an age- and sex-matched group of control subjects but was less than that in a group of alcoholics. There was no significant relationship between CT scan appearances and the duration of benzodiazepine therapy. The clinical significance of the findings was unclear. [ 69 ]
In 1986, it was presumed that permanent brain damage may result from chronic use of benzodiazepines similar to alcohol-related brain damage . [ 70 ] However, alcohol has many off target effects which prelude its toxic effects, including direct organ toxicity, while benzodiazepines are highly selective in their mechanism of action and present with a significantly greater therapeutic index than alcohol.
In 1987, 17 inpatient people who used high doses of benzodiazepines non-medically have anecdotally shown enlarged cerebrospinal fluid spaces with associated cerebral atrophy .
Cerebral atrophy reportedly appeared to be dose dependent with low-dose users having less atrophy than higher-dose users. [ 71 ]
However, a CT study in 1987 found no evidence of cerebral atrophy in prescribed benzodiazepine users. [ 72 ]
In 1989, in a 4- to 6-year follow-up study of 30 inpatient people who used benzodiazepines non-medically, Neuropsychological function was found to be permanently affected in some people with long-term high dose non-medical use of benzodiazepines. Brain damage similar to alcoholic brain damage was observed. The CT scan abnormalities showed dilatation of the ventricular system . However, unlike people who consume excessive alcohol, people who use sedative hypnotic agents non-medically showed no evidence of widened cortical sulci . The study concluded that, when cerebral disorder is diagnosed in people who abuse high doses of sedative hypnotics, it is often permanent. [ 73 ] However, sampling bias limits extrapolation to other populations or contexts, as does the lack of ability to show causation from the observations made.
A CT study in 1993 investigated brain damage in benzodiazepine users and found no overall differences to a healthy control group. [ 74 ]
A study in 2000 found that long-term benzodiazepine therapy does not result in brain abnormalities. [ 75 ]
Withdrawal from high-dose use of nitrazepam anecdotally was alleged in 2001 to have caused severe shock of the whole brain with diffuse slow activity on EEG in one patient after 25 years of use. After withdrawal, abnormalities in hypofrontal brain wave patterns persisted beyond the withdrawal syndrome, which suggested to the authors that organic brain damage occurred from chronic high-dose use of nitrazepam. [ 76 ]
Professor Heather Ashton , a leading expert on benzodiazepines from Newcastle University Institute of Neuroscience, has stated that there is no structural damage from benzodiazepines, and advocates for further research into long-lasting or possibly permanent symptoms of long-term use of benzodiazepines as of 1996. [ 77 ] She has stated that she believes that the most likely explanation for lasting symptoms is persisting but slowly resolving functional changes at the GABA A benzodiazepine receptor level. Newer and more detailed brain scanning technologies such as PET scans and MRI scans had as of 2002 to her knowledge never been used to investigate the question of whether benzodiazepines cause functional or structural brain damage. [ 78 ]
A 2022 study employing florbetapir ( 18 F) PET and MRI to obtain Total Standardized Uptake Value Ratio (SUVR) of brain amyloid load and hippocampal volume (HV), respectively, in a sample of chronic BZD users and nonusers, was conducted in older adults with minor memory/cognitive complaints/issues. [ 79 ] After controlling for multiple confounding variables, chronic BZD users were more likely to present with depression, anxiety, and apathy than nonusers, while the MRI subgroup of BZD users were more likely to be females with lower education and greater clinical impairment on the clinical dementia rating scale. The results showed that SUVR of brain amyloid load and hippocampal volume were significantly lower and higher, respectively, in BZD users compared with nonusers. Although short-acting BZDs had a more significant effect on increased HV, the dose and duration of use were not observed to have an effect. Thus, the following study found a beneficial effect associated with BZD use on two significant diagnostic markers of Alzheimer’s disease.
A 2018 review of the research found a likely causative role between the use of benzodiazepines and an increased risk of dementia, [ 80 ] but the exact nature of the relationship is still a matter of debate. [ 81 ]
Benzodiazepines, when introduced in 1961, were widely believed to be safe drugs but as the decades went by increased awareness of adverse effects connected to their long-term use became known. Recommendations for more restrictive medical guidelines followed. [ 82 ] [ 83 ] Concerns regarding the long-term effects of benzodiazepines have been raised since 1980. [ 84 ] These concerns are still not fully answered. A review in 2006 of the literature on use of benzodiazepine and nonbenzodiazepine hypnotics concluded that more research is needed to evaluate the long-term effects of hypnotic drugs. [ 85 ] The majority of the problems of benzodiazepines are related to their long-term use rather than their short-term use. [ 86 ] There is growing evidence of the harm of long-term use of benzodiazepines, especially at higher doses. In 2007, the Department of Health recommended that individuals on long-term benzodiazepines be monitored at least every 3 months and also recommended against long-term substitution therapy in benzodiazepine drug misusers due to a lack of evidence base for effectiveness and due to the risks of long-term use. [ 87 ] The long-term effects of benzodiazepines are very similar to the long-term effects of alcohol consumption (apart from organ toxicity) and other sedative-hypnotics. Withdrawal effects and dependence are not identical. Dependence can be managed, with a medical professional of course, but withdrawal can be fatal. Physical dependence and withdrawal are very much related but not the same thing. A report in 1987 by the Royal College of Psychiatrists in Great Britain reported that any benefits of long-term use of benzodiazepines are likely to be far outweighed by the risks of long-term use. [ 88 ] Despite this benzodiazepines are still widely prescribed. The socioeconomic costs of the continued widespread prescribing of benzodiazepines is high. [ 89 ]
In 1980, the Medical Research Council (United Kingdom) recommended that research be conducted into the effects of long-term use of benzodiazepines [ 90 ] A 2009 British Government parliamentary inquiry recommended that research into the long-term effects of benzodiazepines must be carried out. [ 91 ] The view of the Department of Health is that they have made every effort to make doctors aware of the problems associated with the long-term use of benzodiazepines, [ 92 ] as well as the dangers of benzodiazepine drug addiction. [ 93 ]
In 1980, the Medicines and Healthcare products Regulatory Agency 's Committee on the Safety of Medicines issued guidance restricting the use of benzodiazepines to short-term use and updated and strengthened these warnings in 1988. When asked by Phil Woolas in 1999 whether the Department of Health had any plans to conduct research into the long-term effects of benzodiazepines, the Department replied, saying they have no plans to do so, as benzodiazepines are already restricted to short-term use and monitored by regulatory bodies. [ 94 ] In a House of Commons debate, Phil Woolas claimed that there had been a cover-up of problems associated with benzodiazepines because they are of too large of a scale for governments, regulatory bodies, and the pharmaceutical industry to deal with. John Hutton stated in response that the Department of Health took the problems of benzodiazepines extremely seriously and was not sweeping the issue under the carpet. [ 95 ] In 2010, the All-Party Parliamentary Group on Involuntary Tranquilliser Addiction filed a complaint with the Equality and Human Rights Commission under the Disability Discrimination Act 1995 against the Department of Health and the Department for Work and Pensions alleging discrimination against people with a benzodiazepine prescription drug dependence as a result of denial of specialised treatment services, exclusion from medical treatment, non-recognition of the protracted benzodiazepine withdrawal syndrome , as well as denial of rehabilitation and back-to-work schemes. Additionally the APPGITA complaint alleged that there is a "virtual prohibition" on the collection of statistical information on benzodiazepines across government departments, whereas with other controlled drugs there are enormous volumes of statistical data. The complaint alleged that the discrimination is deliberate, large scale and that government departments are aware of what they are doing. [ 96 ]
The Medical Research Council (UK) held a closed meeting among top UK medical doctors and representatives from the pharmaceutical industry between 30 October 1980 and 3 April 1981. The meeting was classified under the Public Records Act 1958 until 2014 but became available in 2005 as a result of the Freedom of Information Act . The meeting was called due to concerns that 10–100,000 people could be dependent; meeting chairman Professor Malcolm Lader later revised this estimate to include approximately half a million members of the British public suspected of being dependent on therapeutic dose levels of benzodiazepines, with about half of those on long-term benzodiazepines. It was reported that benzodiazepines may be the third- or fourth-largest drug problem in the UK (the largest being alcohol and tobacco). The chairman of the meeting followed up after the meeting with additional information, which was forwarded to the Medical Research Council neuroscience board, raising concerns regarding tests that showed definite cortical atrophy in 2 of 14 individuals tested and borderline abnormality in five others. He felt that, due to the methodology used in assessing the scans, the abnormalities were likely an underestimate, and more refined techniques would be more accurate. Also discussed were findings that tolerance to benzodiazepines can be demonstrated by injecting diazepam into long-term users; in normal subjects, increases in growth hormone occurs, whereas in benzodiazepine-tolerant individuals this effect is blunted. Also raised were findings in animal studies that showed the development of tolerance in the form of a 15 percent reduction in binding capacity of benzodiazepines after seven days administration of high doses of the partial agonist benzodiazepine drug flurazepam and a 50 percent reduction in binding capacity after 30 days of a low dose of diazepam. The chairman was concerned that papers soon to be published would "stir the whole matter up" and wanted to be able to say that the Medical Research Council "had matters under consideration if questions were asked in parliament". The chairman felt that it "was very important, politically that the MRC should be 'one step ahead'" and recommended epidemiological studies be funded and carried out by Roche Pharmaceuticals and MRC sponsored research conducted into the biochemical effects of long-term use of benzodiazepines. The meeting aimed to identify issues that were likely to arise, alert the Department of Health to the scale of the problem and identify the pharmacology and nature of benzodiazepine dependence and the volume of benzodiazepines being prescribed. The World Health Organization was also interested in the problem and it was felt the meeting would demonstrate to the WHO that the MRC was taking the issue seriously. Among the psychological effects of long-term use of benzodiazepines discussed was a reduced ability to cope with stress. The chairman stated that the "withdrawal symptoms from valium were much worse than many other drugs including, e.g., heroin". It was stated that the likelihood of withdrawing from benzodiazepines was "reduced enormously" if benzodiazepines were prescribed for longer than four months. It was concluded that benzodiazepines are often prescribed inappropriately, for a wide range of conditions and situations. Dr Mason ( DHSS ) and Dr Moir ( SHHD ) felt that, due to the large numbers of people using benzodiazepines for long periods of time, it was important to determine the effectiveness and toxicity of benzodiazepines before deciding what regulatory action to take. [ 90 ]
Controversy resulted in 2010 when the previously secret files came to light over the fact that the Medical Research Council was warned that benzodiazepines prescribed to millions of patients appeared to cause cerebral atrophy similar to hazardous alcohol use in some patients and failed to carry out larger and more rigorous studies. The Independent on Sunday reported allegations that "scores" of the 1.5 million members of the UK public who use benzodiazepines long-term have symptoms that are consistent with brain damage. It has been described as a "huge scandal" by Jim Dobbin , and legal experts and MPs have predicted a class action lawsuit. A solicitor said she was aware of the past failed litigation against the drug companies and the relevance the documents had to that court case and said it was strange that the documents were kept 'hidden' by the MRC. [ 97 ]
Professor Lader, who chaired the MRC meeting, declined to speculate as to why the MRC declined to support his request to set up a unit to further research benzodiazepines and why they did not set up a special safety committee to look into these concerns. Professor Lader stated that he regrets not being more proactive on pursuing the issue, stating that he did not want to be labeled as the guy who pushed only issues with benzos. Professor Ashton also submitted proposals for grant-funded research using MRI, EEG, and cognitive testing in a randomized controlled trial to assess whether benzodiazepines cause permanent damage to the brain, but similarly to Professor Lader was turned down by the MRC. [ 97 ]
The MRC spokesperson said they accept the conclusions of Professor Lader's research and said that they fund only research that meets required quality standards of scientific research, and stated that they were and continue to remain receptive to applications for research in this area. No explanation was reported for why the documents were sealed by the Public Records Act. [ 97 ]
Jim Dobbin , who chaired the All-Party Parliamentary Group for Involuntary Tranquilliser Addiction, stated that:
Many victims have lasting physical, cognitive and psychological problems even after they have withdrawn. We are seeking legal advice because we believe these documents are the bombshell they have been waiting for. The MRC must justify why there was no proper follow-up to Professor Lader's research, no safety committee, no study, nothing to further explore the results. We are talking about a huge scandal here. [ 97 ]
The legal director of Action Against Medical Accidents said urgent research must be carried out and said that, if the results of larger studies confirm Professor Lader's research, the government and MRC could be faced with one of the biggest group actions for damages the courts have ever seen, given the large number of people potentially affected. People who report enduring symptoms post-withdrawal such as neurological pain, headaches, cognitive impairment, and memory loss have been left in the dark as to whether these symptoms are drug-induced damage or not due to the MRC's inaction, it was reported. Professor Lader reported that the results of his research did not surprise his research group given that it was already known that alcohol could cause permanent brain changes. [ 97 ]
Benzodiazepines spurred the largest-ever class-action lawsuit against drug manufacturers in the United Kingdom, in the 1980s and early 1990s, involving 14,000 patients and 1,800 law firms that alleged the manufacturers knew of the potential for dependence but intentionally withheld this information from doctors. At the same time, 117 general practitioners and 50 health authorities were sued by patients to recover damages for the harmful effects of dependence and withdrawal . This led some doctors to require a signed consent form from their patients and to recommend that all patients be adequately warned of the risks of dependence and withdrawal before starting treatment with benzodiazepines. [ 98 ] The court case against the drug manufacturers never reached a verdict; legal aid had been withdrawn, leading to the collapse of the trial, and there were allegations that the consultant psychiatrists, the expert witnesses, had a conflict of interest. This litigation led to changes in British law , making class-action lawsuits more difficult. [ 99 ]
Benzodiazepines have been found to cause teratogenic malformations. [ 100 ] The literature concerning the safety of benzodiazepines in pregnancy is unclear and controversial. Initial concerns regarding benzodiazepines in pregnancy began with alarming findings in animals but these do not necessarily cross over to humans. Conflicting findings have been found in babies exposed to benzodiazepines. [ 101 ] A recent analysis of the Swedish Medical Birth Register found an association with preterm births, low birth weight and a moderate increased risk for congenital malformations. An increase in pylorostenosis or alimentary tract atresia was seen. An increase in orofacial clefts was not demonstrated, however, and it was concluded that benzodiazepines are not major teratogens. [ 102 ]
Neurodevelopmental disorders and clinical symptoms are commonly found in babies exposed to benzodiazepines in utero . Benzodiazepine-exposed babies have a low birth weight but catch up to normal babies at an early age, but smaller head circumferences found in exposed infants persists. Other adverse effects of benzodiazepines taken during pregnancy are deviating neurodevelopmental and clinical symptoms including craniofacial anomalies, delayed development of pincer grasp, deviations in muscle tone and pattern of movements. Motor impairments in the babies are impeded for up to 1 year after birth. Gross motor development impairments take 18 months to return to normal but fine motor function impairments persist. [ 103 ] In addition to the smaller head circumference found in benzodiazepine-exposed babies mental retardation , functional deficits, long-lasting behavioural anomalies, and lower intelligence occurs. [ 104 ] [ 105 ]
Benzodiazepines, like many other sedative hypnotic drugs, cause apoptotic neuronal cell death. However, benzodiazepines do not cause as severe apoptosis to the developing brain as alcohol does. [ 106 ] [ 107 ] [ 108 ] The prenatal toxicity of benzodiazepines is most likely due to their effects on neurotransmitter systems , cell membranes and protein synthesis . [ 105 ] This, however, is complicated in that neuropsychological or neuropsychiatric effects of benzodiazepines, if they occur, may not become apparent until later childhood or even adolescence . [ 109 ] A review of the literature found data on long-term follow-up regarding neurobehavioural outcomes is very limited. [ 110 ] However, a study was conducted that followed up 550 benzodiazepine-exposed children, which found that, overall, most children developed normally. There was a smaller subset of benzodiazepine-exposed children who were slower to develop, but by four years of age most of this subgroup of children had normalised. There was a small number of benzodiazepine-exposed children who had continuing developmental abnormalities at 4-year follow-up, but it was not possible to conclude whether these deficits were the result of benzodiazepines or whether social and environmental factors explained the continuing deficits. [ 111 ]
Concerns regarding whether benzodiazepines during pregnancy cause major malformations, in particular cleft palate, have been hotly debated in the literature. A meta analysis of the data from cohort studies found no link but meta analysis of case–control studies did find a significant increase in major malformations. (However, the cohort studies were homogenous and the case–control studies were heterogeneous, thus reducing the strength of the case–control results). There have also been several reports that suggest that benzodiazepines have the potential to cause a syndrome similar to fetal alcohol syndrome , but this has been disputed by a number of studies. As a result of conflicting findings, use of benzodiazepines during pregnancy is controversial. The best available evidence suggests that benzodiazepines are not a major cause of birth defects , i.e. major malformations or cleft lip or cleft palate . [ 112 ]
Significant toxicity from benzodiazepines can occur in the elderly as a result of long-term use. [ 113 ] Benzodiazepines , along with antihypertensives and drugs affecting the cholinergic system, are the most common cause of drug-induced dementia affecting over 10 percent of patients attending memory clinics. [ 114 ] [ 115 ] Long-term use of benzodiazepines in the elderly can lead to a pharmacological syndrome with symptoms including drowsiness , ataxia , fatigue, confusion , weakness , dizziness , vertigo , syncope , reversible dementia , depression , impairment of intellect, psychomotor and sexual dysfunction , agitation , auditory and visual hallucinations , paranoid ideation , panic , delirium , depersonalization , sleepwalking , aggressivity , orthostatic hypotension and insomnia . Depletion of certain neurotransmitters and cortisol levels and alterations in immune function and biological markers can also occur. [ 116 ] Elderly individuals who have been long-term users of benzodiazepines have been found to have a higher incidence of post-operative confusion. [ 117 ] Benzodiazepines have been associated with increased body sway in the elderly, which can potentially lead to fatal accidents including falls. Discontinuation of benzodiazepines leads to improvement in the balance of the body and also leads to improvements in cognitive functions in the elderly benzodiazepine hypnotic users without worsening of insomnia. [ 118 ]
A review of the evidence has found that whilst long-term use of benzodiazepines impairs memory, its association with causing dementia is not clear and requires further research. [ 119 ] A more recent study found that benzodiazepines are associated with an increased risk of dementia and it is recommended that benzodiazepines be avoided in the elderly. [ 120 ] A later study, however, found no increase in dementia associated with long-term usage of benzodiazepine. [ 37 ]
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The psychological and physiological effects of meditation have been studied. In recent years, studies of meditation have increasingly involved the use of modern instruments, such as functional magnetic resonance imaging and electroencephalography , which are able to observe brain physiology and neural activity in living subjects, either during the act of meditation itself or before and after meditation. Correlations can thus be established between meditative practices and brain structure or function. [ 1 ]
Since the 1950s, hundreds of studies on meditation have been conducted, but many of the early studies were flawed and thus yielded unreliable results. [ 2 ] [ 3 ] Another major review article also cautioned about possible misinformation and misinterpretation of data related to the subject. [ 4 ] [ 5 ] Contemporary studies have attempted to address many of these flaws with the hope of guiding current research into a more fruitful path. [ 6 ]
However, the question of meditation's place in mental health care is far from settled, and there is no general consensus among experts. Though meditation is generally deemed useful, recent meta-analyses show small-to-moderate effect sizes. This means that the effect of meditation is roughly comparable to that of the standard self-care measures like sleep, exercise, nutrition, and social intercourse. Importantly, it has a worse safety profile than these standard measures (see section on adverse effects). [ 7 ] [ 8 ] [ 9 ] [ 10 ] [ 11 ] A recent meta-analysis also indicates that the increased mindfulness experienced by mental health patients may not be the result of explicit mindfulness interventions but more of an artefact of their mental health condition (e.g., depression, anxiety) as it is equally experienced by the participants that were placed in the control condition (e.g., active controls, waiting list). This raises further questions as to what exactly meditation does, if anything, that is significantly different from the heightened self-monitoring and self-care that follows in the wake of spontaneous recovery or from the positive effects of encouragement and care that are usually provided in ordinary healthcare settings (see the section on the difficulties studying meditation). [ 12 ] There also seems to be a critical moderation of the effects of meditation according to individual differences. In one meta-analysis from 2022, involving a total of 7782 participants, the researchers found that a higher baseline level of psychopathology (e.g., depression) was associated with deterioration in mental health after a meditation intervention and thus was contraindicated. [ 13 ]
A previous [ timeframe? ] study commissioned by the American Agency for Healthcare Research and Quality found that meditation interventions reduce multiple negative dimensions of psychological stress. [ 10 ] Other systematic reviews and meta-analyses show that mindfulness meditation has mental health benefits, including reductions in depression symptoms, [ 14 ] [ 15 ] [ 16 ] improvements in mood, [ 17 ] strengthening of stress-resilience, [ 17 ] and attentional control. [ 17 ] Mindfulness interventions also appear promising for managing depression in youth. [ 18 ] [ 19 ] Mindfulness meditation is useful for managing stress, [ 15 ] [ 20 ] [ 21 ] [ 17 ] anxiety, [ 14 ] [ 15 ] [ 21 ] and also appears to be effective in treating substance use disorders . [ 22 ] [ 23 ] [ 24 ] In 2016, Hilton and colleagues published a meta-analysis of 30 randomized controlled trials, found high-quality evidence for improvement in depressive symptoms. [ 25 ] Other reviews have concluded that mindfulness meditation can enhance the psychological functioning of breast cancer survivors, [ 15 ] is effective for people with eating disorders [ 26 ] [ 27 ] and may also be effective in treating psychosis. [ 28 ] [ 29 ] [ 30 ]
Studies have also shown that rumination and worry contribute to mental illnesses such as depression and anxiety, [ 31 ] and mindfulness-based interventions are effective in the reduction of worry. [ 31 ] [ 32 ] Some studies suggest that mindfulness meditation contributes to a more coherent and healthy sense of self and identity when considering aspects such as a sense of responsibility, authenticity, compassion, self-acceptance, and character. [ 33 ] [ 34 ]
The analgesic effect of mindfulness meditation may involve multiple brain mechanisms , of which chronic pain is shown to have a slight decrease when performing meditation. [ 35 ] Current research demonstrates a lack of high-quality data to support a strong case for clinical prescription of meditation, however future research may further change our understanding of chronic pain treatment and mindfulness, [ 36 ] but there are too few studies to allow conclusions about its effects on chronic pain . [ 37 ]
Mindfulness meditation alters the brain, leading to a heightened ability to improve emotions. [ 38 ] In an 8-week mindfulness meditation study, Gotink et al. results showed activity in the amygdala, insula, cingulate cortex, and hippocampus to decrease. [ 38 ] Short-term brain changes such as these are correlated to effects seen in people who have practiced mindfulness over longer periods such as months or years. Another meta-analysis found preliminary evidence for effects in the prefrontal cortex and other brain regions associated with body awareness. [ 39 ] However, these results should be interpreted with caution as funnel plots indicate that publication bias is an issue in meditation research. [ 40 ] A 2016 review using 78 functional neuroimaging studies suggests that different meditation styles result in different brain activity. [ 41 ] While other studies have found structural changes in the brain may occur, most studies have utilized weak methodology. [ 40 ]
Psychological and Buddhist conceptualizations of mindfulness both highlight awareness and attention training as key components in which levels of mindfulness can be cultivated with the practice of mindfulness meditation. [ 42 ] [ 43 ] [ 17 ] Focused attention meditation (FAM) and open monitoring meditation (OMM) are distinct types of mindfulness meditation; FAM refers to the practice of intently maintaining focus on one object, whereas OMM is the progression of general awareness of one's surroundings while regulating thoughts. [ 44 ] [ 45 ] Some forms of Buddhist mindfulness meditation may lead to greater cognitive flexibility . [ 46 ]
In an active randomized controlled study completed in 2019, participants who practiced mindfulness meditation demonstrated a greater improvement in awareness and attention than participants in the active control condition. [ 17 ] Alpha wave neural oscillation power (which is usually associated with an alert resting state) has been shown to be increased by mindfulness in both healthy subjects and patients. [ 47 ]
Tasks of sustained attention relate to vigilance and the preparedness that aids in completing a particular task goal. Psychological research into the relationship between mindfulness meditation and the sustained attention network has revealed the following:
Research shows meditation practices lead to greater emotional regulation abilities. Mindfulness can help people become more aware of thoughts in the present moment, and this increased self-awareness leads to better processing and control over one's responses to surroundings or circumstances. [ 62 ] [ 63 ]
Positive effects of this heightened awareness include a greater sense of empathy for others, increased positive thinking patterns, and reduced anxiety. [ 63 ] [ 62 ] Reductions in rumination also have been found following mindfulness meditation practice, contributing to the development of positive thinking and emotional well-being. [ 64 ]
Emotional reactivity can be measured and reflected in brain regions related to the production of emotions. [ 65 ] It can also be reflected in tests of attentional performance, indexed in poorer performance in attention-related tasks. The regulation of emotional reactivity as initiated by attentional control capacities can be taxing to performance, as attentional resources are limited. [ 66 ]
It is debated as to whether top-down executive control regions such as the dorsolateral prefrontal cortex (DLPFC), [ 76 ] are required [ 74 ] or not [ 67 ] to inhibit reactivity of the amygdala activation related to the production of evoked emotional responses. Arguably, an initial increase in activation of executive control regions developed during mindfulness training may lessen with increasing mindfulness expertise. [ 77 ]
Furthermore, current research data is inconclusive and incomplete in linking the positive effects of mindful meditation with a variety of reported positive effects. Additional high-fidelity studies are needed before a complete understanding of the full effects of mindfulness can be reached. [ 36 ] [ 38 ] [ 35 ]
Research has shown stress reduction benefits from mindfulness. [ 78 ] [ 79 ] [ 80 ] A 2019 study tested the effects of meditation on the psychological well-being, work stress, and blood pressure of employees working in the United Kingdom. One group of participants was instructed to meditate once a day using a smartphone mindfulness app, while the control group did not engage in meditation. Measurements of well-being, stress, and perceived workplace support were taken for both groups before the intervention and then again after four months. Based on self-report questionnaires, the participants who engaged in meditation showed a significant increase in psychological well-being and perceived workplace support. The meditators also reported a significant decrease in anxiety and stress levels. [ 80 ]
Another study conducted to understand the association between mindfulness, perceived stress, and work engagement indicated that mindfulness was associated with lower perceived stress and higher work engagement. [ 81 ]
An additional study from 2021 looking at the effect of centering meditation intervention on stress levels of college students saw a statistically significant improvement in stress and mindfulness levels over time. Inclusive of this was the finding that it helped reduce stress and the variance of that stress on a participant-to-participant basis. [ 82 ]
Other research shows decreased stress levels in people who engage in meditation after shorter periods of time as well. Evidence of significant stress reduction was found after only three weeks of meditation intervention. [ 17 ] Brief, daily meditation sessions can alter one's behavioral response to stressors, improving coping mechanisms and decreasing the adverse impact caused by stress. [ 83 ] [ 84 ] A study from 2016 examined anxiety and emotional states of naive meditators before and after a seven-day meditation retreat in Thailand. Results displayed a significant reduction in perceived stress after this traditional Buddhist meditation retreat. [ 84 ]
Cancer diagnosis and treatment often comes with psychological complications; as an example, rates of psychological distress in breast cancer patients in China was a staggering 49%. [ 85 ] A meta-analysis of 869 studies saw that Mindfulness-based stress reduction resulted in significant decreases of anxiety and depression levels in cancer patients. [ 86 ]
Chronic insomnia is often associated with anxious hyperarousal and frustration over the inability to sleep. [ 87 ] Mindfulness has been shown to reduce insomnia and improve sleep quality, although self-reported measures show larger effects than objective measures. [ 87 ] [ 88 ]
A 2008 study looked at the combination of meditation and cognitive behavioral therapy in treating those meeting the diagnostic criteria for psychophysiological insomnia. Results after the 6-week intervention showed statistically significant improvements in pre-sleep arousal, sleep-related distress, and insomnia. [ 89 ]
Sleep disturbance is a common symptom of cancer that many patients face, with incidence rates ranging anywhere from 30 - 90%. [ 90 ] A 2023 meta-analysis looking at the relationship between meditation and cancer-related sleep disturbance saw significant immediate effects in patients on self-reported sleep disturbance levels. [ 90 ]
Cancer itself and the treatment patients go through often comes with varying side effects including fatigue, nausea, sleep disturbance, pain, and others. [ 91 ] Over the past few decades, the connection between meditation and its effect on cancer has been a topic of interest for researchers. Mindfulness meditation, in particular, has been shown to influence health outcomes associated with cancer diagnosis and treatment, including pain, mental health and sleep disturbance, which have susceptibility to play off of one another.
Pain is a common side effect of cancer patients, with 30-50% of patients experiencing moderate to severe levels. [ 92 ] Mindfulness-based cognitive therapy was found to garner statistically significant effects in regards to self-reported pain levels in cancer patients after 8 weeks. [ 93 ] Inclusive of this was another finding that pain severity may be lowered through mindfulness-based interventions. [ 94 ] Research saw that mindfulness meditation may additionally be effective in pain management as the patient's report of the pain can be lessened through diverting their attention away from the symptoms, thus increasing pain tolerance. [ 92 ] Though studies have brought about significant evidence of meditation's effect on pain management, scholars believe that it should not be used as a mainstay treatment for cancer pain without further research. [ 92 ]
Cancer diagnosis and treatment often comes with psychological complications; as an example, rates of psychological distress in breast cancer patients in China was a staggering 49%. [ 95 ] Armed with this information, researchers began to look into interventions to help alleviate the mental suffering of patients, including meditation. When regarding cancer-related effects on mental health, a meta-analysis of 869 studies saw that Mindfulness-based stress reduction resulted in lower anxiety and depression levels in cancer patients as well as improvement in physical functioning. [ 96 ] In a review of 29 randomized controlled trials looking into nonpharmacological mediations for impairment of cognition relating to cancer, meditation was found to be the best option when compared to other interventions including yoga, acupuncture, and cognitive training. [ 97 ]
Sleep disturbance is a common symptom of cancer that many patients face, with incidence rates ranging anywhere from 30 - 90%. [ 98 ] Disturbances in sleep have been found to result in other consequences such as stress, fatigue, and cognitive impairment. [ 98 ] Research has been conducted on the connection between meditation and sleep disturbance to see if it is deemed effective as an intervention. A meta analysis of 56 studies saw mindfulness to result in significant immediate effects on sleep disturbance. [ 98 ] Additional results yielded statistically significant short-term effects on sleep in patients when compared to education and breath control. [ 98 ] Sleep disturbance was found to be relieved in patients who underwent mindfulness-based intervention. [ 99 ] When accounting for longevity, a meta-analysis found the effects of mindfulness on sleep to last around 6 months. [ 98 ]
A large part of mindfulness research is dependent on technology. As new technology develops, new imaging techniques will become helpful in this field. Real-time fMRI might give immediate feedback and guide participants through the programs. It could also be used to train and evaluate mental states more easily during meditation itself. [ 100 ]
Vipassana or "insight" meditation is a form of mindfulness meditation attributed within the Buddhist tradition to the Buddha Gautama. The practice aims to increase a sense of awareness of the present moment. The practitioner becomes a quiet observer of their thoughts, emotions, and sensations; allowing them to come and go without passing judgement. [ 101 ] [ 102 ] A plethora of evidence now exists to suggest that vipassana meditation does indeed lead to increased mindfulness, but the benefits of the practice do not stop there. It has also been found to reduce stress and increase both self-kindness and overall well-being. [ 103 ]
Electroencephalography studies on Vipassana meditators seemed to indicate significant increase in parieto - occipital gamma rhythms in experienced meditators (35–45 Hz). [ 104 ] In another study conducted by NIMHANS on Vipassana meditators, researchers found readings associated with improved cognitive processing after a session of meditation, with distinct and graded difference in the readings between novice meditators and experienced meditators. [ 105 ]
Khoury and colleagues (2017) conducted a meta-analysis including a total of 21 studies and 2,912 participants. The study aimed to evaluate the effects of traditional vipassana meditation retreats in various populations including advanced meditators, novice meditators, and incarcerated individuals. More specifically, it explored the psychological outcomes including anxiety symptoms, depressive symptoms, and stress following the retreats, evaluated the impacts of the retreats on levels of mindfulness, and explored variables moderating the effectiveness of traditional retreats. Results suggested that traditional vipassana meditation retreats were moderately effective at improving psychological outcomes, with novice meditators and members of the general population experiencing particularly large reductions in anxiety, depression, and stress when compared to both experienced meditators and incarcerated individuals. Moreover, the results suggested an increased capacity for emotional regulation, acceptance, compassion, and mindfulness as well as higher quality of life scores following the retreats across all populations. These results held steady even at follow-up. [ 106 ]
An essential component to the Vipassana mediation approach is the focus on awareness, referring to bodily sensations and psychological status. In a study conducted by Zeng et al. (2013), awareness was described as the acknowledgement of consciousness which is monitoring all aspects of the environment. [ 107 ] This definition differentiates the concept of awareness from mindfulness. The emphasis on awareness, and the way it assists in monitoring emotion, is unique to this meditative practice.
Kundalini yoga has proved to increase the prevention of cognitive decline and evaluate the response of biomarkers to treatment, thereby shedding light on the underlying mechanisms of the link between Kundalini Yoga and cognitive impairment. For the study, 81 participants aged 55 and older who had subjective memory complaints and met criteria for mild cognitive impairment, indicated by a total score of 0.5 on the Clinical Dementia Rating Scale. The results showed that at 12 weeks, both the yoga group showed significant improvements in recall memory and visual memory and showed a significant sustained improvement in memory up to the 24-week follow-up, the yoga group showed significant improvement in verbal fluency and sustained significant improvements in executive functioning at week 24. In addition, the yoga cohort showed significant improvement in depressive symptoms, apathy, and resilience from emotional stress. This research was provided by Helen Lavretsky, M.D. and colleagues. [ 108 ] In another study, Kundalini Yoga did not show significant effectiveness in treating obsessive-compulsive disorders compared with Relaxation/Meditation. [ 109 ]
Sahaja yoga meditation is regarded as a mental silence meditation, and has been shown to correlate with particular brain [ 110 ] [ 111 ] and brain wave [ 112 ] [ 113 ] [ 114 ] characteristics. One study has led to suggestions that Sahaja meditation involves 'switching off' irrelevant brain networks for the maintenance of focused internalized attention and inhibition of inappropriate information. [ 115 ] Sahaja meditators appear to benefit from lower depression [ 116 ] and scored above control group for emotional well-being and mental health measures on SF-36 ratings. [ 117 ] [ 118 ] [ 119 ]
A study comparing practitioners of Sahaja Yoga meditation with a group of non-meditators doing a simple relaxation exercise, measured a drop in skin temperature in the meditators compared to a rise in skin temperature in the non-meditators as they relaxed. The researchers noted that all other meditation studies that have observed skin temperature have recorded increases and none have recorded a decrease in skin temperature. This suggests that Sahaja Yoga meditation, being a mental silence approach, may differ both experientially and physiologically from simple relaxation. [ 114 ]
In a 2006 review, Transcendental Meditation proved comparable with other kinds of relaxation therapies in reducing anxiety. [ 109 ] In another 2006 review, study participants demonstrated a one Hertz reduction in electroencephalography alpha wave frequency relative to controls. [ 120 ]
A 2012 meta-analysis published in Psychological Bulletin , which reviewed 163 individual studies, found that Transcendental Meditation performed no better overall than other meditation techniques in improving psychological variables. [ 121 ]
A 2013 statement from the American Heart Association said that Transcendental Meditation could be considered as a treatment for hypertension , although other interventions such as exercise and device-guided breathing were more effective and better supported by clinical evidence. [ 122 ]
A 2014 review found moderate evidence for improvement in anxiety, depression and pain with low evidence for improvement in stress and mental health-related quality of life. [ 123 ] [ 124 ]
Transcendental Meditation may reduce blood pressure , according to a 2015 review that compared it to control groups . A trend over time indicated that practicing Transcendental Meditation may lower blood pressure. Such effects are comparable to other lifestyle interventions . Conflicting findings across reviews and a potential risk of bias indicated the necessity of further evidence. [ 125 ] [ 126 ]
Several meta-analyses have examined the effects of mindful meditation on one’s loving, kindness, and compassionate disposition and behaviors. Significant increases in self-reported self-compassion. Compassion, and well-being were reported alongside decreases in depression and anxiety. [ 127 ] Another study indicated an increase in positive emotions. [ 128 ] [ 129 ] There may be further benefits that are yet to be discovered, with only preliminary data on mindfulness and mediation. Further studies and explorations into the effects of mindful meditation on the self are needed to draw further conclusions. [ 129 ] [ 128 ] [ 127 ]
The medial prefrontal and posterior cingulate cortices have been found to be relatively deactivated during meditation by experienced meditators using concentration, loving-kindness, and choiceless awareness meditation. [ 130 ] In addition experienced meditators were found to have stronger coupling between the posterior cingulate, dorsal anterior cingulate, and dorsolateral prefrontal cortices both when meditating and when not meditating. [ 131 ] Over time meditation can actually increase the integrity of both gray and white matter . The added amount of gray matter found in the brain stem after meditation improves communication between the cortex and all other areas within the brain. [ 132 ] [ 133 ] Meditation often stimulates a large network of cortical regions including the frontal and parietal regions, lateral occipital lobe , the insular cortex , thalamic nuclei , basal ganglia , and the cerebellum region in the brain. These parts of the brain are connected with attention and the default network of the brain which is associated to day dreaming. [ 134 ]
In addition, both meditation and yoga have been found to have impacts on the brain, specifically the caudate. [ 136 ] Strengthening of the caudate has been shown in meditators as well as yogis. The increased connectedness of the caudate has potential to be responsible for the improved well-being that is associated with yoga and meditation. [ 135 ]
Meditation is under preliminary research to assess possible changes in grey matter concentrations. [ 40 ]
Published research suggests that meditation can facilitate neuroplasticity and connectivity in brain regions specifically related to emotion regulation and attention. [ 137 ] [ 138 ]
Non-directive forms of meditation where the meditator lets their mind wander freely can actually produce higher levels of activity in the default mode network when compared to a resting state or having the brain in a neutral place. [ 139 ] [ 140 ] These Non directive forms of meditation allows the meditators to have better control over thoughts during everyday activities or when focusing on specific task due to a reduced frustration at the brains mind wandering process. [ 140 ] When given a specific task, meditation can allow quicker response to changing environmental stimuli. Meditation can allow the brain to decrease attention to unwanted responses of irrelevant environmental stimuli and a reduces the Stroop effect . Those who meditate have regularly demonstrated more control on what they focus their attention on while maintaining a mindful awareness on what is around them. [ 141 ] Experienced meditators have been shown to have an increased ability when it comes to conflict monitoring [ 17 ] and find it easier to switch between competing stimuli. [ 142 ] Those who practice meditation experience an increase of attentional resources in the brain and steady meditation practice can lead to the reduction of the attentional blink due to a decreased mental exertion when identifying important stimuli. [ 142 ]
Studies have shown that meditation has both short-term and long-term effects on various perceptual faculties. In 1984 a study showed that meditators have a significantly lower detection threshold for light stimuli of short duration. [ 143 ] In 2000 a study of the perception of visual illusions by zen masters, novice meditators, and non-meditators showed statistically significant effects found for the Poggendorff Illusion but not for the Müller-Lyer Illusion . The zen masters experienced a statistically significant reduction in initial illusion (measured as error in millimeters) and a lower decrement in illusion for subsequent trials. [ 144 ] Tloczynski has described the theory of mechanism behind the changes in perception that accompany mindfulness meditation thus: "A person who meditates consequently perceives objects more as directly experienced stimuli and less as concepts… With the removal or minimization of cognitive stimuli and generally increasing awareness, meditation can therefore influence both the quality (accuracy) and quantity (detection) of perception." [ 144 ] Brown points to this as a possible explanation of the phenomenon: "[the higher rate of detection of single light flashes] involves quieting some of the higher mental processes which normally obstruct the perception of subtle events." [ 145 ] In other words, the practice may temporarily or permanently alter some of the top-down processing involved in filtering subtle events usually deemed noise by the perceptual filters. [ 145 ]
Meditation enhances memory capacity specifically in the working memory and increases executive functioning by helping participants better understand what is happening moment for moment. [ 146 ] [ 147 ] Those who meditate regularly have demonstrated the ability to better process and distinguish important information from the working memory and store it into long-term memory with more accuracy than those who do not practice meditation techniques. [ 133 ] Meditation may be able to expand the amount of information that can be held within working memory and by so doing is able to improve IQ scores and increase individual intelligence. [ 139 ] The encoding process for both audio and visual information has been shown to be more accurate and detailed when meditation is used. [ 142 ] Though there are limited studies on meditation's effects on long-term memory, because of meditations ability to increase attentional awareness, episodic long-term memory is believed to be more vivid and accurate for those who meditate regularly. Meditation has also shown to decrease memory complaints from those with Alzheimer's disease which also suggests the benefits meditation could have on episodic long-term memory which is linked to Alzheimer's. [ 148 ]
Electroencephalography activity slows as a result of meditation. [ 149 ] Some types of meditation may lead to a calming effect by reducing sympathetic nervous system activity while increasing parasympathetic nervous system activity. Or, equivalently, that meditation produces a reduction in arousal and increase in relaxation. [ 150 ]
Herbert Benson , founder of the Mind-Body Medical Institute, which is affiliated with Harvard University and several Boston hospitals, reports that meditation induces a host of biochemical and physical changes in the body collectively referred to as the "relaxation response". [ 151 ] The relaxation response includes changes in metabolism, heart rate, respiration, blood pressure and brain chemistry. Benson and his team have also done clinical studies at Buddhist monasteries in the Himalayan Mountains. [ 152 ] Benson wrote The Relaxation Response to document the benefits of meditation, which in 1975 were not yet widely known. [ 153 ]
There is no good evidence to indicate that meditation affects the brain in aging. [ 154 ]
Studies have shown meditators may have higher happiness than control groups, although this may be due to non-specific factors such as meditators having better general self-care. [ 155 ] [ 116 ]
Preliminary research indicates a possible relationship between the volume of gray matter in the right precuneus area of the brain and both meditation and the subject's subjective happiness score. [ 156 ] A recent study found that participants who engaged in a body-scan meditation for about 20 minutes self-reported higher levels of happiness and decrease in anxiety compared to participants who just rested during the 20-minute time span. These results suggest that an increase in awareness of one's body through meditation causes a state of selflessness and a feeling of connectedness. This result then leads to reports of positive emotions. [ 157 ]
Meditation has been shown to reduce pain perception. [ 158 ] An intervention known as mindfulness-based pain management (MBPM) has been subject to a range of studies demonstrating its effectiveness. [ 159 ] [ 160 ]
Meditation and mindfulness have also been correlated with unpleasant experiences, but the potential for adverse effects from meditation has received limited attention in scientific articles [ 161 ] [ 162 ] [ 163 ] [ web 1 ] and the popular press. [ web 2 ] [ web 3 ] [ web 4 ] [ web 5 ] One in-depth investigation was produced by the Financial Times , and published in 2024 as a five-part podcast, entitled "Untold: The Retreat". In the podcast, the FT's special investigations editor Madison Marriage looks at claims of harm from people who had attended Goenka Vipassana retreats. [ 164 ] [ 165 ] [ 166 ] [ 167 ] [ 168 ]
According to Farias et al. (2020) the most common adverse effects of meditation are anxiety and depression. [ 161 ] Other adverse affects may include depersonalization [ 161 ] or altered sense of self or the world, [ 169 ] distorted emotions or thoughts, and, in a few cases, visual and auditory psychosis, and with pre-existing historical factors suicide. [ 161 ] [ 170 ] [ 171 ] [ 172 ]
Schlosser et al. (2019) reported that, of 1,232 regular meditators with at least two months of meditation experience, about a quarter reported having had particularly unpleasant meditation-related experiences (such as anxiety, fear, distorted emotions or thoughts, altered sense of self or the world), which they thought may have been caused by their meditation practice. Meditators with high levels of repetitive negative thinking and those who only engage in deconstructive meditation were more likely to report unpleasant side effects. Adverse effects were less frequently reported in women and religious meditators. [ 173 ]
Meditation also has an addictive potential as it both offers biochemical rewards and socially acceptable avenues for escapism (like internet use, social media, substance abuse). [ 174 ] [ 175 ] Using spiritual ideas and practices "to sidestep or avoid facing unresolved emotional issues, psychological wounds, and unfinished developmental tasks" [ 176 ] is known as Spiritual bypass , a term introduced in the mid 1980s by John Welwood , a Buddhist teacher and psychotherapist. [ 176 ]
"Zen sickness", exhaustion caused by prolonged intense practice and self-neglect is described by Hakuin [ 177 ] and Bankei .
In recent years both the soundness of the scientific foundations and the desirability of the societal effects of mindfulness have been questioned. [ 178 ] [ 179 ] [ 180 ] [ 181 ]
Britton et al. (2019), in a study on the effects of mindfulness-based programs (MBPs), found negative side-effects in 37% of the sample while lasting bad effects in 6–14% of the sample. [ 182 ] Most of the side effects were related to signs of dysregulated arousal (i.e., hyperarousal and dissociation ). The majority of these adverse events occurred as a result of regular practice at home or during class something that challenges the notion that it is only intense practice that can give rise to negative experiences; as it turns out intense all-day retreats or working with difficulty practice accounts for only 6% of adverse effects. The symptoms most readily recognized as negative were those of hyperarousal (e.g., anxiety and insomnia ). On the other hand, while dissociation symptoms (e.g., emotional blunting , derealization , and self-disturbance) were both less frequent and less likely to be appraised as negative, they were still associated with more than 5–10 times greater risk for lasting bad effects… This means that re-appraisal of dissociative symptoms via non-judgmental acceptance is not sufficient to prevent impairment in functioning and should not constitute the only response. Instead, training in how to recognize dissociative symptoms as potential indicators of the need for intervention, which have recently been added to some mindfulness teacher training programs may be important. [ 183 ]
There is also mounting evidence that mindfulness can disturb various prosocial behaviors. By blunting emotions , in particular the social emotions of guilt and shame, it may produce deficits in the feelings of empathy and remorse thus creating calm but callous practitioners. Hafenbrack et al. (2022), in a study on mindfulness with 1400 participants, found that focused-breathing meditation can dampen the relationship between transgressions and the desire to engage in reparative prosocial behaviors. [ 184 ] Poullin et al. (2021) found that mindfulness can increase the trait of selfishness . The study, consisting of two interrelated parts and totaling 691 participants, found that a mindfulness induction, compared to a control condition, led to decreased prosocial behavior. This effect was moderated by self-construals such that people with relatively independent self-construals became less prosocial while people with relatively interdependent self-construals became more so. In the western world where independent self-construals generally predominate meditation may thus have potentially detrimental effects. [ 185 ]
These new findings about mindfulness' socially problematic effects imply that it can be contraindicated to use mindfulness as a tool to handle acute personal conflicts or relational difficulties; in the words of Andrew Hafenbrack, one of the authors of the study, “If we 'artificially' reduce our guilt by meditating it away, we may end up with worse relationships, or even fewer relationships”. [ 186 ] [ 184 ] In line with this, a meta-analysis by Kreplin et al. (2018) concluded that meditation only has a limited effect in increasing prosocial behaviours (e.g., empathy, compassion). [ 11 ]
Mindfulness is not helpful if it used to avoid facing ongoing problems or emerging crises in the meditator's life, in which case it will function as just another form of experiential avoidance and potentially exacerbate the crisis. In such situations, it may instead be helpful to apply mindful attitudes while actively engaging with current problems. [ 187 ] [ page needed ] According to the NIH , meditation and mindfulness should not be used as a replacement for conventional health care or as a reason to postpone seeing a doctor . [ 188 ]
Organizations such as Cheetah House and Meditating in Safety document research on problems arising in meditation, and offer help for meditators in distress or those recovering from meditation-related health problems. In some cases, adverse effects may be attributed to "improper use of meditation" [ 189 ] or the aggravation of a preexisting condition; however, developing research in this area suggests the need for deeper engagement with the causes of severe distress, which previous "meditation teachers have perhaps too quickly and rather insensitively dismissed as pre-existing or unrelated psychopathology". [ 190 ] Where meditation is prescribed or offered as a treatment,
principles of informed consent require that treatment choice be based in part on the balance of benefits to harms, and therefore can only be made if harms are adequately measured and known. [ 191 ]
In June 2007, the United States National Center for Complementary and Integrative Health published an independent, peer-reviewed, meta-analysis of the state of meditation research, conducted by researchers at the University of Alberta Evidence-based Practice Center. The report reviewed 813 studies involving five broad categories of meditation: mantra meditation, mindfulness meditation , yoga , tai chi , and qigong , and included all studies on adults through September 2005, with a particular focus on research pertaining to hypertension , cardiovascular disease , and substance abuse . The report concluded:
Scientific research on meditation practices does not appear to have a common theoretical perspective and is characterized by poor methodological quality. Future research on meditation practices must be more rigorous in the design and execution of studies and in the analysis and reporting of results. (p. 6)
It noted that there is no theoretical explanation of health effects from meditation common to all meditation techniques. [ 2 ]
A version of this report subsequently published in the Journal of Alternative and Complementary Medicine in 2008 stated: "Most clinical trials on meditation practices are generally characterized by poor methodological quality with significant threats to validity in every major quality domain assessed." This was despite a statistically significant increase in quality of all reviewed meditation research, in general, over time between 1956 and 2005. Of the 400 clinical studies, 10% were found to be good quality. A call was made for rigorous study of meditation. [ 6 ] These authors also noted that this finding is not unique to the area of meditation research and that the quality of reporting is a frequent problem in other areas of complementary and alternative medicine (CAM) research and related therapy research domains.
Of more than 3,000 scientific studies that were found in a comprehensive search of 17 relevant databases, only about 4% had randomised controlled trials (RCTs), which are designed to exclude the placebo effect. [ 2 ]
In a 2013 meta-analysis, Awasthi argued that meditation is defined poorly and despite the research studies showing clinical efficacy, exact mechanisms of action remain unclear. [ 192 ] A 2017 commentary was similarly mixed, [ 4 ] [ 5 ] with concerns including the particular characteristics of individuals who tend to participate in mindfulness and meditation research. [ 193 ]
A 2013 statement from the American Heart Association evaluated the evidence for the effectiveness of Transcendental Meditation as a treatment for hypertension as "unknown/unclear/uncertain or not well-established", and stated: "Because of many negative studies or mixed results and a paucity of available trials... other meditation techniques are not recommended in clinical practice to lower BP at this time." [ 194 ] According to the American Heart Association, while there are promising results about the impact of meditation in reducing blood pressure and managing insomnia, depression and anxiety, it is not a replacement for healthy lifestyle changes and is not a substitute for effective medication. [ 195 ]
The term meditation encompasses a wide range of practices and interventions rooted in different traditions, but research literature has sometimes failed to adequately specify the nature of the particular meditation practice(s) being studied. [ 196 ] Different forms of meditation practice may yield different results depending on the factors being studied. [ 196 ]
The presence of a number of intertwined factors including the effects of meditation, the theoretical orientation of how meditation practices are taught, the cultural background of meditators, and generic group effects complicates the task of isolating the effects of meditation: [ 78 ]
Numerous studies have demonstrated the beneficial effects of a variety of meditation practices. It has been unclear to what extent these practices share neural correlates. Interestingly, a recent study compared electroencephalogram activity during a focused-attention and open monitoring meditation practice from practitioners of two Buddhist traditions. The researchers found that the differences between the two meditation traditions were more pronounced than the differences between the two types of meditation. These data are consistent with our findings that theoretical orientation of how a practice is taught strongly influences neural activity during these practices. However, the study used long-term practitioners from different cultures, which may have confounded the results. [ 197 ]
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Efficacy is the ability to perform a task to a satisfactory or expected degree. The word comes from the same roots as effectiveness , and it has often been used synonymously, although in pharmacology a distinction is now often made between efficacy and effectiveness . [ 1 ]
The word efficacy is used in pharmacology and medicine to refer both to the maximum response achievable from a pharmaceutical drug in research settings, [ 2 ] and to the capacity for sufficient therapeutic effect or beneficial change in clinical settings.
In pharmacology, efficacy ( E max ) is the maximum response achievable from an applied or dosed agent, for instance, a small molecule drug. [ 2 ] Intrinsic activity is a relative term for a drug's efficacy relative to a drug with the highest observed efficacy. [ 3 ] It is a purely descriptive term that has little or no mechanistic interpretation.
In order for a drug to have an effect, it needs to bind to its target, and then to affect the function of this target. The target of a drug is commonly referred to as a receptor , but can in general be any chemically sensitive site on any molecule found in the body. The nature of such binding can be quantified by characterising how tightly these molecules, the drug and its receptor, interact: this is known as the affinity . Efficacy, on the other hand, is a measure of the action of a drug once binding has occurred. The maximum response, E max , will be reduced if efficacy is sufficiently low.
The definition of efficacy has been object for discussion. [ 4 ] The only way in which absolute measures of efficacy have been obtained is by single ion channel analysis of ligand gated ion channels. It is still not possible to do this for G protein-linked receptors.
In the case of the glycine receptor and the nicotinic acetylcholine receptor (muscle type), it has been proposed by Sivilotti et al . that opening of the ion channel involves two steps after agonist is bound. Firstly a conformation change to a higher affinity (but still shut) form, followed by the conformation change from shut to open. [ 5 ] [ 6 ] It was found that partial agonism results from deficiency in the first step, and that the opening and shutting steps are essentially the same for both full and partial agonists. This has been confirmed and extended by Sine and colleagues (2009). [ 7 ] The implication of this work [ 6 ] is that efficacy has to be defined by at least two equilibrium constants (or, more generally, by four rate constants).
The combined influences of affinity and efficacy determine how effectively a drug will produce a biological effect, a property known as potency .
In medicine, efficacy is the capacity for beneficial change (or therapeutic effect ) of a given intervention (for example a drug, medical device , surgical procedure , or a public health intervention). [ 8 ] Establishment of the efficacy of an intervention is often done relative to other available interventions, with which it will be compared. [ 9 ] Specifically, efficacy refers to "whether a drug demonstrates a health benefit over a placebo or other intervention when tested in an ideal situation, such as a tightly controlled clinical trial." [ 10 ] These studies focus on a primary parameter to be shown statistically different between placebo and intervention groups. Comparisons of this type are called 'explanatory' randomized controlled trials , whereas 'pragmatic' trials are used to establish the effectiveness of an intervention regarding also non-specific parameters. [ citation needed ]
Effectiveness refers to "how the drug works in a real-world situation", [ 11 ] and is "often lower than efficacy because of interactions with other medications or health conditions of the patient, sufficient dose or duration of use not prescribed by the physician or followed by the patient, or use for an off-label condition that had not been tested." [ 10 ] [ 12 ]
In agriculture and forestry, efficacy is used to describe whether a pesticide is effective in controlling a pest or disease. [ 13 ]
In Protestant Theology (esp. in Lutheran but also in Calvinist doctrine) efficacy is an attribute of Scripture . The efficacy of Scripture means that it is united with the power of the Holy Spirit and with it, not only demands, but also creates the acceptance of its teaching [ 14 ] [ 15 ] [ 16 ] and that this teaching produces faith and obedience . Efficacy further means that Holy Scripture is not a dead letter, but rather, the power of the Holy Spirit is inherent in it [ 17 ] [ 18 ] [ 19 ] and that Scripture does not compel a mere intellectual assent to its doctrine, resting on logical argumentation, but rather it creates the living agreement of faith . [ 20 ] [ 21 ] The Smalcald Articles affirm, "in those things which concern the spoken, outward Word , we must firmly hold that God grants His Spirit or grace to no one, except through or with the preceding outward Word." [ 22 ] The Formula of Concord teaches that when humans reject the calling of the Holy Spirit, it is not a result of the Word being less efficacious. Instead, contempt for the means of grace is the result of "the perverse will of man, which rejects or perverts the means and instrument of the Holy Ghost, which God offers him through the call , and resists the Holy Ghost, who wishes to be efficacious, and works through the Word ..." [ 23 ]
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Egg paleopathology is the study of evidence for illness, injury, and deformity in fossilized eggs . A variety of pathological conditions afflicting eggs have been documented in the fossil record . Examples include eggshell of abnormal thickness and fossil eggs with multiple layers of eggshell. The identification of egg paleopathologies is complicated by the fact that even healthy eggs can be modified during or after fossilization. Paleontologists can use techniques like cathodoluminescence or thin sectioning to identify true paleopathologies in fossil eggs. Despite the diversity of paleopathologies known from fossil eggs, the vast majority of conditions known to afflict modern eggs have not yet been seen among fossils.
Differences in preservation and diagenesis make it difficult to confidently identify eggshell pathologies in the fossil record. Multilayered eggshell identification can be complicated if the secondary eggshell is disconnected from the original. When this happens the two shells can vary in structure and may even be mistaken as coming from different types of eggs. [ 1 ] Stacked eggshells from collapsed or compressed eggs may resemble multilayered eggshells but in thin cross-sections viewed under a microscope the stacked shell will have mammilae facing opposite directions whereas egg shells that developed in layers on top of each other will have mammilae facing the same direction. [ 2 ] Also, in stacked shells the layer separating the shells will resemble the sediment surrounding the fossil and in multilayer the layer between shells will resemble the primary shell more than the surrounding sediment. [ 3 ]
Cathodoluminescence can be used to distinguish pathological egg shell from egg shell that has been altered diagenetically. Rigid egg shells, except in turtles, are composed of calcite. Since calcitic and aragonitic structures do not luminesce, signs of luminescence point to alterations to the chemical composition or structure of the shell. Magnesium-Calcite is sometimes replaced by Manganese-Calcite, which luminesces bright red-orange or yellow orange. In multilayer eggs the shells will appear the same color, but the shell membrane between them tends to be replaced by manganese-calcite that luminseces bright orange. Manganese is the primary instigator of luminescence whereas iron hinders it. [ 4 ]
Abnormally thin eggshell can allow excessive evaporation to dehydrate the embryo or shell membrane. Dehydrated membranes have a negative impact on gas permeability of the egg. Eggshell pathology can cause the shell to be so thin that the egg collapses. [ 5 ] Abnormally thin eggshell has been attributed to Hypselosaurus priscus and some experts have speculated that this was the cause of the species' extinction, with vegetation changes, climatic change and overcrowding being the original impetus for the shell thinning. However, there are alternative explanations for the thin eggshell not dependent on pathology. Later researchers found resorption craters in the basal caps at the base of the columns, meaning that the eggs hatched. Some researchers postulated that the thinner " Hypselosaurus priscus " eggshells came from different taxa than the thicker eggshells, and subsequent researchers have come to support this idea. Another potential explanation for variation in eggshell thickness is that the thinner eggs were laid by younger individuals than older ones. There are also natural variations of eggshell thickness within a single species. [ 6 ] Stressful environmental conditions may have resulted in dinosaur egg shells thinning. This may have played a role in dinosaur extinction, but is a controversial subject. [ 7 ]
Multilayered eggs are known from the fossil record and were first reported from the Late Cretaceous of France and later India and Argentina. More recent discoveries of this pathology have been in Late Cretaceous strata in Montana and Late Jurassic strata in Utah. [ 7 ] Multilayered eggs can cause embryos to suffocate as the extraneous layer's pore canals won't line up well enough with the original layers' to allow gas to travel to the embryo. [ 8 ] Multilayered dinosaur eggs are known from, in order of discovery, France, Spain, Mongolia, India, Argentina, Canada, Montana, and Utah. [ 9 ] Most multilayered dinosaur eggs are of the megaloolithid oofamily with a discretispherulitic morphotype . Other types of fossil eggs with these pathologies are prismatic , filispherulitic , dendrospherulitic , and prolatospherulitic morphotypes. Multilayered fossil eggs resemble those of modern forms in sometimes having incomplete extra layers and pore canals that don't properly align. The shell membranes of these eggs have been either dissolved or been replaced with secondary calcite . In the pathological specimens from Spain and Montana the redundant shell layer is as thick as in the original. In the specimen from Alberta it is only three fourths of the thickness of the original. The Utah specimen's pathological layer is only half that of the original. The egg is split open but still connected at one side. Some aspects of this egg suggests it was still in its mother's body when it was buried. [ 10 ] The term ovum in ovo has been used for multilayered dinosaur eggs although this is inaccurate use of the term. Pathologies of eggshell are difficult to recognize in fossil specimens. [ 11 ] Multilayered eggs are most common in the discretispherulitic egg morphotype and less common in others. This type of egg is attributed to sauropods. The greater abundance may indicate that these eggs were more prone to such pathologies, but are most likely due to a larger sample size of them. The pathological egg still inside its mother from Utah is a unique occurrence. [ 12 ]
Oligocene strata from West Germany have produced 27 multilayered gecko eggs. Another multilayered egg from West Germany is not a gecko egg. The shells of these eggs were broken in the typical fashion of hatching eggs, interpreted by the original describers as meaning that the pathological eggshell was not fatal to the developing embryos. In a 2001 survey of fossil eggshell pathologies, Karl F. Hirsch criticized these authors on the basis that multilayered eggs were "very unlikely" to allow embryos to hatch because even if the pores of the secondary shell layer were perfectly aligned with those of the primary layer the eggshell would still be too thick for the struggling neonate to break free. [ 10 ]
Extraspherulitic growth units are sometimes found in otherwise normal eggs. In Jurassic specimens from Colorado these are rare, but occupy almost the entire shell layer in specimens obtained from Late Cretaceous Montana. [ 13 ] Egg shell has been recovered from the Milk River area of Alberta which may have been partially dissolved and then had additional calcite deposited on it. [ 14 ]
Irregularities in the surface of an egg and unusual egg shapes can be caused by convulsions or contractions of the uterus . Eggs can be wrinkled, bulged, ridged, or have nodules. Eggs can be restricted, bound, or truncated. These pathological eggs often have shell units and internal microstructures that are not interlocked as tightly as those of healthy eggs. These phenomena have not been found in fossil eggs. [ 15 ] Ovum in ovo has low preservation potential and has not yet been observed in the fossil record. [ 7 ] The term ovum in ovo has been used for multilayered dinosaur eggs although this is inaccurate use of the term. Pathologies of eggshell are difficult to recognize in fossil specimens. [ 11 ] Hirsch concludes that the majority of pathological phenomena known to occur in modern eggs are not represented in the fossil record. [ 16 ]
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Eggs per gram (eggs/g) is a laboratory test that determines the number of eggs per gram of feces in patients suspected of having a parasitological infection , such as schistosomiasis . [ 1 ]
Measuring the number of eggs per gram is the primary diagnostic method for schistosomiasis, as opposed to a blood test . Eggs per gram or another analyse like larvae per gram of faeces is one of the most important experiments that is done in parasitology labs.
Methods to count the number of eggs per gram:
This article related to pathology is a stub . You can help Wikipedia by expanding it .
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On 4 August 1985, Chinese gambler Huang Zhiheng murdered a family of ten in the Eight Immortals Restaurant in Portuguese Macau (present-day Macau SAR, China ). He stabbed or strangled each of his victims to death before dismembering their bodies and disposing of their remains in the ocean and dumpsters. Huang purportedly committed the murders because the Zheng family owed him a gambling debt of 600,000 patacas (or US$ 75,047).
The Eight Immortals Restaurant ( Chinese : 八仙飯店 , Portuguese : Casa de Rasto Pat Sin ) was a Chinese restaurant in the Iao Hon [ zh ; zh-yue ] section of Nossa Senhora de Fátima parish in Macau, then a Portuguese colony . [ 1 ] [ 2 ] The modest dining establishment, connected to the Eight Immortals Hotel, was owned and operated by Zheng Lin (鄭林), a former street hawker who had moved his business from a stand into a formal restaurant in the 1960s. Zheng lived near his restaurant with his family, who helped him run the business. The restaurant was a financial success, but Zheng and his wife were noted to be heavy gamblers . [ 3 ]
Huang Zhiheng ( simplified Chinese : 黄志恒 ; traditional Chinese : 黃志恆 , sometimes spelled Huang Chih-heng) was born in Mainland China as Chen Shuliang ( simplified Chinese : 陈梓梁 ; traditional Chinese : 陳梓梁 ) before emigrating to Hong Kong, then under British rule, in the 1970s. In 1973, Huang murdered a man over a debt at his victim's home in Quarry Bay . He fled to Guangzhou , where he cut off the tip of his left index finger and burned his fingerprints in an attempt to avoid being linked to the murder. After living in Guangzhou for several years, Huang married the daughter of his landlord, named Ms. Li. The woman's family disapproved of the marriage, so the couple eloped to Macau. Huang subsequently became involved in Macau's gambling scene, becoming acquainted with the Zhengs in the process. Huang was aged around 50 at the time of this encounter. [ 4 ] [ 3 ]
During one evening of gambling in 1984, Huang and Zheng became involved in a series of high stakes bets against each other. In the end, Huang won 180,000 patacas (or US$20,000) from Zheng and his wife. The Zhengs were unable to pay the debt, so a verbal agreement was made that the Zheng family would cede their restaurant's mortgage to Huang if the debt was not repaid within one year. Huang agreed. The family remained indebted after this year. Huang would later claim that not only had the family failed to repay him but continued to lose money in further bets, allegedly owing a total of 600,000 patacas (or US$75,047). [ 4 ]
The Zheng family were last seen alive by a delivery man on the afternoon of 4 August 1985. That evening, after the restaurant had closed, Huang entered the establishment and demanded that the family pay 30,000 patacas (he later claimed that he dropped his demand to 20,000 patacas) of the debt they owed him. Huang grew increasingly agitated when Zheng Lin refused to turn over ownership of the restaurant. Eventually, Huang became physically aggressive, taking Zheng's son hostage and forcing the other eight family members to bind and gag each other. Huang later claimed that one family member broke free and started to scream, causing him to stab her in the neck with a broken bottle he had brandished as a weapon. He then proceeded to kill all nine family members, either by strangulation or with the bottle. He briefly left the restaurant to lure one of Zheng's sisters inside, where he killed her as well. [ 4 ]
Huang dismembered the bodies over the course of eight hours and wrapped them in plastic trash bags, which he then dumped into the ocean or threw into dumpsters. Afterwards he cleaned the restaurant, recovered some money and a safe key from Zheng's corpse, and spent the night at Zheng's nearby residence. [ 5 ] [ 3 ] The next morning, the delivery man found the restaurant locked, with a note on the door stating that it would be closed for three days. The delivery man visited the Zheng residence, where Huang answered the door and claimed the family had taken a trip to the mainland.
On 8 August 1985, a swimmer found eight pieces of human limbs in Hac Sa Beach [ Note 1 ] . It was originally theorised that the body parts came from a group of illegal immigrants from the mainland who had been eaten by sharks, but an examination of the limbs revealed that precise cuts had been used to sever them. This finding prompted a police investigation and a search for potential missing persons . Over the next few days, forensic evidence determined that the limbs belonged to at least four separate people. A further three body parts were found on local beaches over the following week. These findings generated significant interest in the press, and several theories were raised as to what had happened. [ 5 ]
Eventually, Macau police traced the severed limbs to the Zheng family, who had been reported missing by relatives. Meanwhile, Huang reopened and continued to operate the restaurant; this was considered unusual but not unwarranted, as he was known to associate with the family and was in possession of the restaurant's ownership documents. He also began collecting rent from the family's former home. Police grew suspicious of Huang and searched his bank holdings, finding documents belonging to Zheng and student ID cards belonging to his children. Huang attempted to flee for the mainland but was captured on 28 September 1986. He was convicted of ten counts of murder on 2 October 1986. Huang's arrest, and the fact that he had continued to run the restaurant after dismembering its former owners, resulted in the urban legend that he had baked his victims into pork buns . The final body parts to be linked to the murders were found in a trash dump in 1989. [ 5 ] [ 4 ] [ 3 ]
Huang was attacked in prison by another inmate on the day after his conviction. He was sent to a hospital to convalesce, where he attempted to escape without success. On 6 October, Huang confessed and detailed to investigators how and why he had killed the Zheng family. His second and fatal suicide attempt took place on 4 December 1986, when he managed to cut his wrists with a bottle cap. Huang left a suicide note and a letter to a local newspaper explaining his actions, stating in his note that his suicide was not due to his crimes but rather to escape his chronic asthma . After his death, what was left of his fingerprints linked him to the 1973 murder in Hong Kong. [ 5 ]
The recovered remains of the Zheng family were later cremated, and the ashes scattered off the coast of Macau by relatives.
After Huang's arrest, the restaurant was immediately closed and seized by police. It was resold by early 1987 and has seen different owners in recent years. Today, the former restaurant and the apartments above it are part of Baxian Hotel.
The events surrounding the Eight Immortals Restaurant murders were depicted in the 1993 Hong Kong movie The Untold Story featuring Anthony Wong . [ 6 ] [ 7 ] [ 8 ] The film featured a fictionalized version of the murder of the Zheng family, and notably played upon the rumors that cannibalism had occurred after the murders. [ 7 ] In China, the film was also released under the names The Human Pork Bun and Human Meat Roast Pork Buns . [ 9 ] [ 10 ]
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Einthoven's triangle is an imaginary formation of three limb leads in a triangle used in the electrocardiography , formed by the two shoulders and the pubis. [ 1 ] The shape forms an inverted equilateral triangle with the heart at the center. It is named after Willem Einthoven , who theorized its existence. [ 2 ]
Einthoven used these measuring points, by immersing the hands and feet in pails of salt water, as the contacts for his string galvanometer , the first practical ECG machine. [ 3 ]
Electrodes may be placed distally or proximally on the limb without affecting the recording. [ 5 ] The right leg electrode acts to reduce interference, and can be placed anywhere without an effect on the ECG results. [ 6 ]
Each lead measures the electric field created by the heart during the depolarization and repolarization of myocytes . The electric field can be represented as a vector that changes continuously and can be measured by recording the voltage difference between electrodes. [ 7 ]
Einthoven's triangle can be helpful in the identification in incorrect placement of leads. Incorrect placement of leads can lead to error in the recording, which can ultimately lead to misdiagnosis.
If the arm electrodes are reversed, lead I changes polarity, causing lead II and lead III to switch. If the right arm electrode is reversed with the leg's electrode, lead II changes polarity, causing lead I to become lead III, and vice versa. Reversal of the left arm and leg causes a change in polarity of lead III and switching of leads I and II. [ 6 ]
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Eisenmenger syndrome or Eisenmenger's syndrome is defined as the process in which a long-standing left-to-right cardiac shunt caused by a congenital heart defect (typically by a ventricular septal defect , atrial septal defect , or less commonly, patent ductus arteriosus ) causes pulmonary hypertension [ 1 ] [ 2 ] and eventual reversal of the shunt into a cyanotic right-to-left shunt . Because of the advent of fetal screening with echocardiography early in life, the incidence of heart defects progressing to Eisenmenger syndrome has decreased.
Eisenmenger syndrome in a pregnant mother can cause serious complications, [ 3 ] though successful delivery has been reported. [ 4 ] Maternal mortality ranges from 30% to 60%, and may be attributed to fainting spells , blood clots forming in the veins and traveling to distant sites , hypovolemia, coughing up blood or preeclampsia . Most deaths occur either during or within the first weeks after delivery. [ 5 ] Pregnant women with Eisenmenger syndrome should be hospitalized after the 20th week of pregnancy, or earlier if clinical deterioration occurs.
Signs and symptoms of Eisenmenger syndrome include the following: [ 6 ]
One of the most severe and common complications of Eisenmenger syndrome is cardiac arrhythmia, especially supraventricular arrhythmias . Approximately 40% of patients diagnosed with Eisenmenger syndrome were also found to have these arrhythmias during routine ECG screenings. These arrhythmias have worse prognosis in patients with Eisenmenger syndrome, compared to the general population, and can be a source of sudden cardiac death . [ 9 ]
A number of congenital heart defects can cause Eisenmenger syndrome, including atrial septal defects , ventricular septal defects , patent ductus arteriosus , and more complex types of acyanotic heart disease . [ 1 ]
Diagnosis of Eisenmenger syndrome is typically conducted via transthoracic echocardiography , which facilitates the identification and evaluation of shunts, anatomical defects, and ventricular function. Following diagnosis, or in some cases of inconclusive diagnosis, a cardiac catheter may be used to both confirm the diagnosis and to assess the patient's pulmonary arterial pressure, an important predictive value for prognosis and treatment. [ 9 ]
If the inciting defect in the heart is identified before it causes significant pulmonary hypertension, it can normally be repaired through surgery, preventing the disease. [ 10 ] After pulmonary hypertension is sufficient to reverse the blood flow through the defect, however, the maladaptation is considered irreversible, and a heart–lung transplant or a lung transplant with repair of the heart is the only curative option.
Transplantation is the final therapeutic option and only for patients with poor prognosis and quality of life. Timing and appropriateness of transplantation remain difficult decisions. [ 5 ] 5-year and 10-year survival ranges between 70% and 80%, 50% and 70%, 30% and 50%, respectively. [ 11 ] [ 12 ] [ 13 ] Since the average life expectancy of patients after lung transplantation is as low as 30% at 5 years, patients with reasonable functional status related to Eisenmenger syndrome have improved survival with conservative medical care compared with transplantation. [ 14 ]
Various medicines and therapies for pulmonary hypertension are under investigation for treatment of the symptoms. [ 15 ]
Antiarrhythmic drugs are important for many patients with Eisenmenger syndrome, as evidence suggests that arrhythmia-induced sudden cardiac death may be the leading cause of death among patients with the disease. These therapies generally aim to restore and maintain sinus rhythm, but the specific interventions chosen will depend on the nature of the patient's arrhythmia. [ 9 ]
Eisenmenger syndrome was named [ 16 ] by Paul Wood after Victor Eisenmenger , who first described [ 17 ] the condition in 1897. [ 18 ]
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El Anfiteatro Anatómico Español ( English: The Spanish Anatomical Amphitheater ) was a Spanish medical journal dedicated to the fields of Medicine , Surgery , and Auxiliary Sciences , founded in the 19th century.
The medical journal was established by Segovian physician Pedro González de Velasco and began publication on 1 February 1873. [ 1 ]
The idea of the journal was realized by Dr. Velasco in Madrid , Spain. Established with Velasco as its founding director, managing director Eduardo García Pérez, and the Editor-in-chief Dr. Ángel Pulido . [ 2 ]
In 1875, upon Dr. Velasco's death, Francisco Vidurre became the administrator of the paper and it was the official organ of the Spanish Anatomical Society . [ 1 ]
On 1 January 1876 it was combined with The Medical Pavilion ( Spanish : El Pabellón Médico ), a magazine by Pedro Mata y Fontanet . [ 3 ] [ 4 ]
El Anfiteatro Anatómico Español was published until 1880, at which point it merged with the Journal of Medicine and Practical Surgery . [ 2 ]
Media related to El Anfiteatro Anatómico Español at Wikimedia Commons
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Elastic therapeutic tape , also called kinesiology tape or kinesiology therapeutic tape , Kinesio tape , k-tape , or KT [ 1 ] is an elastic cotton strip with an acrylic adhesive that is purported to ease pain and disability from athletic injuries and a variety of other physical disorders. [ 2 ] [ 3 ] [ 4 ] In individuals with chronic musculoskeletal pain, research suggests that elastic taping may help relieve pain, but not more than other treatment approaches, and no evidence indicates that it can reduce disability in chronic pain cases. [ 5 ]
No convincing scientific evidence indicates that such products provide any demonstrable benefit in excess of a placebo , with some declaring it a pseudoscientific treatment. [ 6 ] [ 7 ]
Kenzo Kase, a Japanese-American chiropractor , developed the product in the 1970s. The company he founded markets variants under the brand name "Kinesio" and takes legal action to prevent the word being used as a genericised trademark . [ 2 ]
A surge in popularity resulted after the product was donated to Olympic athletes in the 2008 Beijing Summer Olympics and 2012 London Summer Olympics . [ 8 ] [ 9 ] The tapes' prominence and mass introduction to the general public have been attributed to Kerri Walsh who wore the tape on her shoulder, and who along with Misty May-Treanor dominated the 2008 beach volleyball event. [ 10 ] In 2012, science journalist Brian Dunning speculated on why he had not seen "a single athlete, pro beach volleyball players included, wear Kinesio Tape outside of the Olympics". He believes that "sponsorship dollars may be entirely responsible for the popularity of Kinesio Tape during televised events." [ 11 ]
The product is a type of thin, elastic cotton tape that can stretch up to 140% of its original length. [ 12 ] As a result, if the tape is applied stretched greater than its normal length, it will "recoil" after being applied and therefore create a pulling force on the skin . This elastic property allows much greater range of motion compared to traditional white athletic tape and can also be left on for long periods before reapplication. [ 13 ]
Designed to mimic human skin, with roughly the same thickness and elastic properties, the tape can be stretched 30–40% longitudinally. [ 12 ] It is a latex-free material with acrylic adhesive, which is heat activated. The cotton fibers allow for evaporation and quicker drying leading to longer wear time, up to 4 days. [ 14 ] How the tape is claimed to affect the body is dependent on the location and how it is applied; the stretch direction, the shape, and the location all supposedly play a role in the tape's hypothetical function. [ 14 ]
Manufacturers have made a wide variety of claims, including that it provides physical support for muscles , tendons , ligaments , and joints . [ 15 ] KT Health's web site at one point claimed the tape "lifts the skin, decompressing the layers of fascia, allowing for greater movement of lymphatic fluid which transports white blood cells throughout the body and removes waste products, cellular debris, and bacteria". [ 16 ] This increase in the interstitial space purportedly reduces pressure on the body's nociceptors , which detect pain, and stimulates mechanoreceptors , to improve overall joint proprioception . [ 17 ] Critics say these claims are not supported by evidence. [ 7 ]
In the 2012 article "Scientists sceptical as athletes get all taped up", Reuters reported that "In a review of all the scientific research so far, published in the Sports Medicine journal in February, researchers found 'little quality evidence to support the use of Kinesio tape over other types of elastic taping in the management or prevention of sports injuries". [ 8 ] Some researchers claim that what athletes are experiencing is just a placebo effect . [ 18 ]
In July 2012, Steven Novella writing in Science-Based Medicine in the article "Olympic Pseudoscience'", examined the use of KT in the larger context of "sports-related pseudoscience". Novella says "The world of sports competition is rife with pseudoscience, false claims, dubious products, superstitions , and magical charms." Novella concluded that "Consumers should be very skeptical of claims made for products marketed as athletic performance enhancing." [ 6 ]
In August 2012, science journalist Brian Dunning reports in "Kinesio Tape: The Evidence" that positive studies of the tape are the result of people being deceived by a "stage magician's trick" – which he describes in detail – that is used to fool subjects into thinking strength or flexibility is being affected, when they are not. He reports that kinesio tape is claimed to be good for a plethora of issues including "pain management, injury treatment, injury prevention, enhanced performance, increased range of motion, and just about anything else an athlete might want." He concludes: "It sounds like a miracle — one simple product that does everything you can imagine. In short, a textbook snake oil product ." [ 11 ]
A 2012 meta analysis found that the efficacy of elastic therapeutic tape in pain relief was trivial, because no reviewed study found clinically important results . The tape "may have a small beneficial role in improving strength, range of motion in certain injured cohorts, and force sense error compared with other elastic tapes, but further studies are needed to confirm these findings". [ 17 ] [ unreliable medical source? ] The same article concluded: "KT had some substantial effects on muscle activity, but it was unclear whether these changes were beneficial or harmful. In conclusion, there was little quality evidence to support the use of KT over other types of elastic taping in the management or prevention of sports injuries" [ 17 ] [ unreliable medical source? ]
A 2014 meta analysis looked at methodological quality of studies, along with overall population effect, and suggested that studies of lower methodological quality are more likely to report beneficial effects of elastic therapeutic taping, thus indicating the perceived effect of using kinesio taping is not real. It also suggested that applying elastic therapeutic tape, "to facilitate muscular contraction has no, or only negligible, effects on muscle strength". [ 19 ]
A 2015 meta analysis found that the taping provided more pain relief than no treatment at all, but was not better than other treatment approaches in patients with chronic musculoskeletal pain. [ 5 ] The same meta analysis did not find any significant changes in disability as a result of taping. [ 5 ]
In March 2018, Science-Based Medicine again examined KT in response to its public use at the 2018 Winter Olympics in the article A Miscellany of Medical Malarkey Episode 3: The Revengening . The article reports that:
The claims made by manufacturers and promoters of the tape are highly implausible, particularly those involving increased muscle strength, improved blood flow to an injured areas, and better lymphatic drainage to reduce swelling. No evidence supports these claims. Pain reduction and injury prevention are also frequently-cited benefits that similarly lack evidence, at least none showing an effect specific to kinesio tape... There is no evidence of a specific benefit related to kinesio tape itself, or to any kind of expert application of it. [ 7 ]
In November 2018, Science-Based Medicine describes a new study published the same month in the online journal BMC Sports Science, Medicine and Rehabilitation which examines the effectiveness of different colors of kinesiology tape, as well as reexamining general effectiveness of kinesiology tape against a placebo. Describing the conclusions of the study, they write:
Nothing mattered. Tape color didn't matter. Color preference didn't matter. "Proper" placement of KT with tension didn't matter. No effect on performance, strength, or function was found in any experimental round compared to the control round for any of the subjects. [ 20 ]
A 2023 systematic review included nine RCTs in their meta-analysis and concluded that KT can significantly reduce pain intensity between baseline and immediately post intervention and between baseline and the short-term follow-up period. However, no significant differences existed between KT’s ability to relieve other symptoms of CNLBP—disability, trunk flexion range of motion (ROM), change in status, fear of movement, isometric endurance of the trunk muscles, or extension—when compared to either sham taping or KT as an adjunct to physical therapy. [ 21 ]
In 2017, KT Health settled a class action lawsuit in Massachusetts, resolving claims of unjust enrichment and untrue and misleading marketing. It agreed to pay $1.75 million to refund half the purchase price of the tape, representing the premium paid above traditional athletic tape. [ 16 ] The brand also agreed to drop claims that the tape "will keep you pain-free", "prevents injury", or provides "24-hour pain relief", and add the disclaimer "not clinicially proven for all injuries". [ 16 ]
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2006
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NP_001265841 NP_001265842 NP_001265843 NP_001265844 NP_001265845 NP_001265846 NP_001265847 NP_001265868
NP_031951
Elastin is a protein encoded by the ELN gene in humans and several other animals. Elastin is a key component in the extracellular matrix of gnathostomes (jawed vertebrates). [ 5 ] It is highly elastic and present in connective tissue of the body to resume its shape after stretching or contracting. [ 6 ] Elastin helps skin return to its original position whence poked or pinched. Elastin is also in important load-bearing tissue of vertebrates and used in places where storage of mechanical energy is required. [ 7 ]
The ELN gene encodes a protein that is one of the two components of elastic fibers . The encoded protein is rich in hydrophobic amino acids such as glycine and proline , which form mobile hydrophobic regions bounded by crosslinks between lysine residues. Multiple transcript variants encoding different isoforms have been found for this gene. [ 8 ] Elastin's soluble precursor is tropoelastin. [ 9 ]
The characterization of disorder is consistent with an entropy-driven mechanism of elastic recoil. It is concluded that conformational disorder is a constitutive feature of elastin structure and function. [ 10 ]
Deletions and mutations in this gene are associated with supravalvular aortic stenosis (SVAS) and the autosomal dominant cutis laxa . [ 8 ] Other associated defects in elastin include Marfan syndrome , emphysema caused by α 1 -antitrypsin deficiency, atherosclerosis , Buschke–Ollendorff syndrome , Menkes syndrome , pseudoxanthoma elasticum , and Williams syndrome . [ 11 ]
Elastosis is the buildup of elastin in tissues, and is a form of degenerative disease . There are a multitude of causes, but the most commons cause is actinic elastosis of the skin, also known as solar elastosis , which is caused by prolonged and excessive sun exposure, a process known as photoaging . Uncommon causes of skin elastosis include elastosis perforans serpiginosa , perforating calcific elastosis and linear focal elastosis . [ 12 ]
In the body, elastin is usually associated with other proteins in connective tissues. Elastic fiber in the body is a mixture of amorphous elastin and fibrous fibrillin . Both components are primarily made of smaller amino acids such as glycine , valine , alanine , and proline . [ 11 ] [ 14 ] The total elastin ranges from 58 to 75% of the weight of the dry defatted artery in normal canine arteries. [ 15 ] Comparison between fresh and digested tissues shows that, at 35% strain, a minimum of 48% of the arterial load is carried by elastin, and a minimum of 43% of the change in stiffness of arterial tissue is due to the change in elastin stiffness. [ 16 ]
Elastin serves an important function in arteries as a medium for pressure wave propagation to help blood flow and is particularly abundant in large elastic blood vessels such as the aorta . Elastin is also very important in the lungs , elastic ligaments , elastic cartilage , the skin , and the bladder . It is present in jawed vertebrates . [ 17 ]
Elastin is a very long-lived protein, with a half-life of over 78 years in humans. [ 18 ]
The feasibility of using recombinant human tropoelastin to enable elastin fiber production to improve skin flexibility in wounds and scarring has been studied. [ 19 ] [ 20 ] After subcutaneous injections of recombinant human tropoelastin into fresh wounds it was found there was no improvement in scarring or the flexibility of the eventual scarring. [ 19 ] [ 20 ]
Elastin is made by linking together many small soluble precursor tropoelastin protein molecules (50-70 kDa ), to make the final massive, insoluble, durable complex. The unlinked tropoelastin molecules are not normally available in the cell, since they become crosslinked into elastin fibres immediately after their synthesis by the cell and export into the extracellular matrix . [ 21 ]
Each tropoelastin consists of a string of 36 small domains , each weighing about 2 kDa in a random coil conformation . The protein consists of alternating hydrophobic and hydrophilic domains, which are encoded by separate exons , so that the domain structure of tropoelastin reflects the exon organization of the gene. The hydrophilic domains contain Lys-Ala (KA) and Lys-Pro (KP) motifs that are involved in crosslinking during the formation of mature elastin. In the KA domains, lysine residues occur as pairs or triplets separated by two or three alanine residues (e.g. AAAKAAKAA) whereas in KP domains the lysine residues are separated mainly by proline residues (e.g. KPLKP).
Tropoelastin aggregates at physiological temperature due to interactions between hydrophobic domains in a process called coacervation . This process is reversible and thermodynamically controlled and does not require protein cleavage . The coacervate is made insoluble by irreversible crosslinking.
To make mature elastin fibres, the tropoelastin molecules are cross-linked via their lysine residues with desmosine and isodesmosine cross-linking molecules. The enzyme that performs the crosslinking is lysyl oxidase , using an in vivo Chichibabin pyridine synthesis reaction. [ 22 ]
In mammals, the genome only contains one gene for tropoelastin, called ELN . The human ELN gene is a 45 kb segment on chromosome 7 , and has 34 exons interrupted by almost 700 introns, with the first exon being a signal peptide assigning its extracellular localization. The large number of introns suggests that genetic recombination may contribute to the instability of the gene, leading to diseases such as SVAS . The expression of tropoelastin mRNA is highly regulated under at least eight different transcription start sites .
Tissue specific variants of elastin are produced by alternative splicing of the tropoelastin gene. There are at least 11 known human tropoelastin isoforms. These isoforms are under developmental regulation, however there are minimal differences among tissues at the same developmental stage. [ 11 ]
This article incorporates text from the United States National Library of Medicine , which is in the public domain .
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Elcatonin is a calcitonin derivative used as an anti- parathyroid agent.
It is transformed from eel's calcitonin by changing the S-S bond into a stable C-N bond. It inhibits the absorption and autolysis of bones and thus leads to lowering of blood calcium. It inhibits bone salts from dissolving and transferring and promotes the excretion of calcium and phosphorus in the urine. It inhibits renal tubules from reabsorbing calcium, phosphorus and sodium and keeps blood calcium at a normal level. [ citation needed ] It is mainly used for remitting or eliminating pain caused by osteoporosis . [ 1 ] [ 2 ]
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Eleazar Parmly (March 13, 1797 – December 13, 1874) was an American dentist in New York City during the 19th-century. He was the first Provost of The University of Maryland School of Dentistry , the first dental school established in the United States . He was the third of five brothers and his three brothers also pursued careers in dentistry.
Parmly was born in 1797, in Braintree, Vermont . At the age of 23, Parmly moved to London to work as a dentist. In 1823, he moved back to the United States to practice in New York City, where he opened a dental shop on Bond Street.
He was responsible for the development of American dentistry from a primitive craft to a respected profession with various national societies and journals. He also furthered the development of dental colleges. In addition to being a well-trained practitioner and educator, Parmly was a gifted poet and set down his autobiography in verse. [ 1 ] He worked with several other famous dentists of the time, such as Solyman Brown , Norman William Kingsley , and Chapin A. Harris .
Parmly died of pneumonia on December 13, 1874, in New York City, at the age of 77.
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An elective [ note 1 ] [ 1 ] is a placement undertaken as part of a medical degree . The content and setting of the placement are largely decided by the student undertaking it, [ 2 ] with some students choosing to spend it in a different country.
Elective placements are not exclusive to medical degrees; many other degree programmes within the field of healthcare also incorporate electives (such as nursing , dentistry and physiotherapy ) and the format is often the same.
An elective represents a unique opportunity for medical students to experience healthcare in a setting unfamiliar to that in which they are accustomed to studying, [ 1 ] or in a place or field of specific interest. [ 3 ] This is classically in a low resource setting, but may also be to experience a specialist field, a place the student is considering working in the future, or for a variety of other reasons.
Placements abroad may provide experience of differing practices, but also allow students to encounter medical conditions they are less used to seeing at home. [ note 2 ] In addition, students often retrospectively describe how their placements broadened their horizons with regards to the social issues affecting healthcare in developing countries. [ 4 ]
A placement in a particular specialist setting may allow students insight into a potential career path, or allow students to participate in the research or implementation of new treatments or practices.
An elective is usually undertaken in the penultimate or final year of study of a medical degree, often after students have finished their final exams. [ 2 ] The university usually specifies the dates during which an elective can be undertaken by students. [ 5 ]
Electives are usually entirely self-arranged, with the student organising travel, accommodation, the placement itself, and other aspects like travel insurance and indemnity insurance. Often the hospital will help organise accommodation, and indemnity cover may be automatic depending on the student's existing policy. Some students recruit the services of companies which specialise in organising medical electives. [ 2 ] Students often share their experiences on the internet, [ 6 ] and good placements become well-known. Popular destinations can fill up 12 months in advance or more [ 5 ]
Most students need to cover travel and living costs, many needing to cover accommodation, and some are charged administration or tuition costs, which can be up to $1,000 or more. [ 7 ]
Many students fund their electives personally, but financial help is occasionally available in the forms of [ 8 ] bursaries, prizes or scholarships, either from the student's university or from societies or private companies. In these cases, the sponsor may require that the student undertakes some form of project whilst on their elective to justify the expense. [ 5 ]
Requirements of students vary from medical school to medical school. Some (such as Aberdeen ) require students to submit a written project as part of their placement, whereas other institutions utilise few formal assessments. [ 5 ]
Students are still subject to all the ethical and professional requirements they would be at their home institution, such as the GMC 's requirement that students at British medical schools "recognise and work within the limits of their competence". [ 9 ] It is immoral and illegal for unregistered medical students to work as if doctors, despite the fact that their level of skill and expertise is often comparable to the professionals they will work with on the placement. [ 2 ]
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Elective surgery or elective procedure is surgery that is scheduled in advance because it does not involve a medical emergency . Semi-elective surgery is a surgery that must be done to preserve the patient's life, but does not need to be performed immediately. Most surgeries are elective, scheduled at a time to suit the surgeon, hospital, and patient.
By contrast, an urgent surgery is one that can wait until the patient is medically stable, but should generally be done within 2 days, and an emergency surgery is one that must be performed without delay; the patient has no choice other than immediate surgery if permanent disability or death is to be avoided. Many surgeries can be performed as either elective or emergency surgeries, depending on the patient's needs.
An elective surgery or elective procedure (from the Latin : eligere , meaning to choose [ 1 ] ) is a surgery that does not involve a medical emergency and is scheduled in advance. Semi-elective surgery is a surgery that must be done to preserve the patient's life, but does not need to be performed immediately.
Most surgical medical treatments are elective, that is, scheduled at a time to suit the surgeon, hospital, and patient. These include inguinal hernia surgery , cataract surgery , mastectomy for breast cancer, and the donation of a kidney by a living donor. [ 2 ]
Elective surgeries include all optional surgeries performed for non-medical reasons. This includes cosmetic surgery , such as facelifts , breast implants , liposuction , and breast reduction , which aim to subjectively improve a patient's physical appearance. Another optional surgery is LASIK —currently the top elective surgery in the United States [ 3 ] —where a patient weighs the risks against increased quality of life expectations. [ 4 ]
When a condition is worsening but has not yet reached the point of a true emergency, surgeons speak of semi-elective surgery : the problem must be dealt with, but a brief delay is not expected to affect the outcome. Semi-elective procedures are typically scheduled within a time frame deemed appropriate for the patient's condition and disease. Removal of a malignancy , for example, is usually scheduled as semi-elective surgery, to be performed within a set number of days or weeks.
In a patient with multiple medical conditions, problems classified as needing semi-elective surgeries may be postponed until emergent conditions have been addressed and the patient is medically stable. For example, whenever possible, pregnant women typically postpone all elective and semi-elective procedures until after giving birth.
In some situations, an urgently needed surgery will be postponed briefly to permit even more urgent conditions to be addressed. In other situations, emergency surgery may be performed at the same time as life-saving resuscitation efforts.
Many surgeries can be performed as either elective or emergency surgeries, depending on the patient's needs. A sudden worsening of gallbladder disease may require immediate removal of the gallbladder by emergency surgery, but this surgery is more commonly scheduled in advance. An appendectomy is considered emergency surgery, but depending upon how early the diagnosis was made, the patient may have more time before the appendix risks rupturing or the infection spreads. Also, in certain emergency conditions, even ones like a heart attack or stroke , surgery may or may not need to be utilized.
Preoperative carbohydrates may decrease amount of time spent in hospital recovering. [ 5 ]
Non-elective surgeries may be classified as urgent or emergency . An urgent surgery is one that can wait until the patient is medically stable, but should generally be done within 2 days. An emergency surgery is one that must be performed without delay; the patient has no choice other than immediate surgery if permanent disability or death is to be avoided. [ 6 ] Urgent surgery is typically performed with 48 hours of diagnosis and emergency surgery is performed as soon as a surgeon is available. A trauma center is a hospital which supports emergency surgery on critically ill patients at the brink of death by ensuring that on a 24/7 basis , a surgeon is always on the premises (or "in-house") to evaluate patients and can take them immediately to the operating room.
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Electrical brain stimulation ( EBS ), also referred to as focal brain stimulation ( FBS ), is a form of electrotherapy and neurotherapy used as a technique in research and clinical neurobiology to stimulate a neuron or neural network in the brain through the direct or indirect excitation of its cell membrane by using an electric current . EBS is used for research or for therapeutic purposes.
Electrical brain stimulation was first used in the first half of the 19th century by pioneering researchers such as Luigi Rolando [ citation needed ] (1773–1831) and Pierre Flourens [ citation needed ] (1794–1867), to study the brain localization of function , following the discovery by Italian physician Luigi Galvani (1737–1798) that nerves and muscles were electrically excitable. The stimulation of the surface of the cerebral cortex by using brain stimulation was used to investigate the motor cortex in animals by researchers such as Eduard Hitzig (1838–1907), Gustav Fritsch (1838–1927), David Ferrier (1842–1928) and Friedrich Goltz (1834–1902). The human cortex was also stimulated electrically by neurosurgeons and neurologists such as Robert Bartholow (1831–1904) and Fedor Krause (1857–1937).
In the following century, the technique was improved by the invention of the stereotactic method by British neurosurgeon pioneer Victor Horsley (1857–1916), and by the development of chronic electrode implants by Swiss neurophysiologist Walter Rudolf Hess (1881–1973), José Delgado (1915–2011) and others, by using electrodes manufactured by straight insulated wire that could be inserted deep into the brain of freely-behaving animals, such as cats and monkeys . This approach was used by James Olds (1922–1976) and colleagues to discover brain stimulation reward and the pleasure center . American-Canadian neurosurgeon Wilder Penfield (1891–1976) and colleagues at the Montreal Neurological Institute used extensive electrical stimulation of the brain cortex in awake neurosurgical patients to investigate the motor and sensory homunculus (the representation of the body in the brain cortex according to the distribution of motor and sensory territories).
EBS remains inextricably entwined with the work of Robert Galbraith Heath , Delgado and Penfield. It's of interest that during cerebral localization studies, neurosurgeon Penfield could not elicit emotional reactions in humans, either by observing spontaneous epilepsy or by electrically stimulating the surface of the cerebral cortex. Neurophysiologist Delgado noted a few exceptions to this rule. In contrast, EBS, via deeply implanted electrodes in localized areas of the brain ( deep brain stimulation ; DBS), elicited both pleasurable and aversive responses in laboratory animals and humans as previously described. [ 1 ] [ 2 ] [ 3 ]
EBS could elicit the ritualistic, motor responses of sham rage in cats by stimulation of the anterior hypothalamus , as well as more complex emotional and behavioral components of "true rage" in both experimental animals by stimulation of the lateral hypothalamus, and in human subjects by stimulating various deep areas of the brain. EBS in human patients with epilepsy could trigger seizures on the surface of the brain and pathologic aggression and rage with stimulation of the amygdala. [ 3 ] [ 4 ]
Two-photon excitation microscopy has shown that microstimulation activates neurons sparsely around the electrode even at low currents (as low as 10 μA) up to distances as far as four millimeters away. This happens without particularly selecting other neurons much nearer the electrode's tip. This is due to activation of neurons being determined by whether they do or do not have axons or dendrites that pass within a radius of 15 μm near the tip of the electrode. As the current is increased the volume around the tip that activates neuron axons and dendrites increases and with this the number of neurons activated. Activation is most likely to be due to direct depolarization rather than synaptic activation . [ 5 ]
A comprehensive review of EBS research compiled a list of many different acute impacts of stimulation depending on the brain region targeted. Following are some examples of the effects documented: [ 6 ]
EBS in face-sensitive regions of the fusiform gyrus caused a patient to report that the faces of the people in the room with him had "metamorphosed" and became distorted: "Your nose got saggy, went to the left. [...] Only your face changed, everything else was the same." [ 7 ]
Examples of therapeutic EBS are:
Strong electric currents may cause a localized lesion in the nervous tissue, instead of a functional reversible stimulation. This property has been used for neurosurgical procedures in a variety of treatments, such as for Parkinson's disease , focal epilepsy and psychosurgery . Sometimes the same electrode is used to probe the brain for finding defective functions, before passing the lesioning current ( electrocoagulation ).
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Electrical cardiometry is a method based on the model of Electrical Velocimetry , and non-invasively measures stroke volume (SV), cardiac output (CO), and other hemodynamic parameters through the use of 4 surface ECG electrodes. Electrical cardiometry is a method trademarked by Cardiotronic, Inc., and is U.S. FDA approved for use on adults, children, and neonates. [ 1 ]
The measured bioimpedance over time can be expressed as the superposition of three components: [ 3 ]
where Z 0 is the quasi-static portion of the electrical impedance (base impedance), ΔZ R are the changes of impedance due to the respiratory cycle, and ΔZ C are the changes of impedance due to the cardiac cycle. ΔZ R is considered an artifact akin to the estimation of stroke volume and is therefore suppressed. Exclusion of derived volumetric data may diminish the overall product.
The timely measurement of ΔZ C (dZ(t)) reveals a waveform with shape similar to an arterial pressure waveform. The calculated first time derivative of dZ(t) is the d Z ( t ) d t {\displaystyle {\frac {dZ(t)}{dt}}} waveform, which contains landmarks that allow determination of left-ventricular ejection time (LVET) and peak aortic blood acceleration. The peak aortic blood acceleration occurs at the steepest slope of the dZ(t) waveform, and at the peak of the d Z ( t ) d t {\displaystyle {\frac {dZ(t)}{dt}}} waveform. [ citation needed ]
Electrical velocimetry (EV) is the model upon which electrical cardiometry is based. EV is based on the fact that the conductivity of the blood in the aorta changes during the cardiac cycle. EV was developed by Dr. Bernstein and Dr. Osypka in 2001, as a new model for interpreting the bioimpedance signals of the thorax. [ 3 ]
Prior to opening of the aortic valve, the red blood cells (erythrocytes) assume a random orientation (there is no blood flow in the aorta). When the electric current is applied from the outer electrodes, the current must circumference these red blood cells, therefore resulting in a higher voltage measurement, and thus, a lower conductivity. Shortly after aortic valve opening, the pulsatile blood flow forces the red blood cells to align in parallel with the blood flow. When the electric current is then applied, it is able to easily pass the red blood cells in the aorta resulting in a lower voltage, and thus, a higher conductivity. The change from random orientation to alignment of red blood cells upon opening of aortic valve generates a characteristic steep increase of conductivity or dZ(t) (corresponding to a steep decrease of impedance) – beat to beat. [ 3 ]
The model considers the peak amplitude of d Z ( t ) d t {\displaystyle {\frac {dZ(t)}{dt}}} divided by the base impedance Z 0 as an index for peak aortic acceleration, and as an index of contractility of the heart, or ICON. The general equation for estimating stroke volume by means of thoracic electrical bioimpedance calculates the product of a patient constant C P (in ml), the mean blood velocity index v ¯ {\displaystyle {\bar {v}}} FT (measured in s −1 during flow time, and FT (flow time measured in s): [ 3 ]
S V T E B = C P ⋅ v ¯ F T ⋅ F T {\displaystyle SV_{TEB}=C_{P}\cdot {\bar {v}}_{FT}\cdot FT}
The model of electrical velocimetry derives the mean blood velocity index v ¯ {\displaystyle {\bar {v}}} FT from the measured index for peak aortic acceleration ICON. [ 4 ] The higher the mean blood velocity during flow time, the more SV the left ventricle ejects. The 'volume of electrically participating tissue' (V EPT ) is used as the patient constant. The V EPT is derived primarily from the body mass. [ 3 ]
Impedance cardiography is a method of non-invasively monitoring hemodynamics, through the use of 4 dual sensors placed on the neck and chest. Both Impedance cardiography and Electrical Cardiometry derive SV and CO from measurements of TEB, but the underlying model is what differs. The Impedance Cardiography model contributes the rapid change of bioimpedance which occurs shortly after aortic valve opening to the expansion of the compliant ascending aorta, assuming that more blood volume temporarily stored in the ascending aorta contributes to a decrease in bioimpedance (or an increase in conductity of the thorax). The underlying model never proved accurate in patients with small cardiac outputs, hence it was never U.S. FDA approved for use in children or neonates. [ citation needed ]
The electrical and impedance signals are processed, and then utilized to measure and calculate hemodynamic parameters such as cardiac output, stroke volume, systemic vascular resistance, thoracic fluid index, ICON (index of contractility), and systolic time ratio.
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Electroanatomic mapping is a method of creating a three dimensional model of the human heart during clinical cardiac electrophysiology procedures.
The fundamental concept of electroanatomic mapping systems is to localize catheters within the heart in three dimensional space (a sort of " GPS " within the heart). Building a 3-D model of the heart with real-time visualization permits reduction in fluoroscopy use. In addition to 3-D structure, the voltage and timing of signals at each point of the heart is recorded to generate different maps to understand and treat different rhythm disturbances.
Each of the three systems utilizes different techniques to localize catheters: [ 1 ]
There are three electroanatomic mapping systems commercially available.
Biosense-Webster, a subsidiary of Johnson & Johnson , produces a cardiac electrophysiology system called CARTO. [ 2 ] The system is designed to visualise the real-time calculated position and orientation of a specialised RF ablation catheter within the patient's heart in order to minimise radiation exposure during fluoroscopy , increase the accuracy of targeted RF ablation and reacquisition of pacing sites for re- ablation . [ 3 ] Its navigation system calculates the position and orientation of the catheter tip, using three known magnetic sources as references. The system uses static magnetic fields that are calibrated and computer controlled. Due to the nature of magnetic fields, the orientation may also be calculated while the tip is stationary. By calculating the strength and orientation of the magnetic fields at a given location, the x,y,z position may be calculated along with the roll, pitch, yaw orientation. [ 2 ]
St. Jude Medical , now a part of Abbott , manufactures EnSite family of cardiac mapping systems, the latest edition being EnSite Precision, which allows speedy heart mapping during catheter ablation with better accuracy to be able to treat cardiac rhythm disturbances. [ 4 ]
Rhythmia is a mapping system developed by Boston Scientific . It has changed names to Opal. [ 5 ]
Mapping systems generate three kinds of data:
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Electrocardiography is the process of producing an electrocardiogram ( ECG or EKG [ a ] ), a recording of the heart's electrical activity through repeated cardiac cycles . [ 4 ] It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the heart [ 5 ] using electrodes placed on the skin. These electrodes detect the small electrical changes that are a consequence of cardiac muscle depolarization followed by repolarization during each cardiac cycle (heartbeat). Changes in the normal ECG pattern occur in numerous cardiac abnormalities, including:
Traditionally, "ECG" usually means a 12-lead ECG taken while lying down as discussed below.
However, other devices can record the electrical activity of the heart such as a Holter monitor but also some models of smartwatch are capable of recording an ECG.
ECG signals can be recorded in other contexts with other devices.
In a conventional 12-lead ECG, ten electrodes are placed on the patient's limbs and on the surface of the chest. The overall magnitude of the heart's electrical potential is then measured from twelve different angles ("leads") and is recorded over a period of time (usually ten seconds). In this way, the overall magnitude and direction of the heart's electrical depolarization is captured at each moment throughout the cardiac cycle . [ 11 ]
There are three main components to an ECG: [ 12 ]
During each heartbeat, a healthy heart has an orderly progression of depolarization that starts with pacemaker cells in the sinoatrial node , spreads throughout the atrium , and passes through the atrioventricular node down into the bundle of His and into the Purkinje fibers , spreading down and to the left throughout the ventricles . [ 12 ] This orderly pattern of depolarization gives rise to the characteristic ECG tracing. To the trained clinician , an ECG conveys a large amount of information about the structure of the heart and the function of its electrical conduction system. [ 13 ] Among other things, an ECG can be used to measure the rate and rhythm of heartbeats, the size and position of the heart chambers , the presence of any damage to the heart's muscle cells or conduction system, the effects of heart drugs, and the function of implanted pacemakers . [ 14 ]
The overall goal of performing an ECG is to obtain information about the electrical functioning of the heart. Medical uses for this information are varied and often need to be combined with knowledge of the structure of the heart and physical examination signs to be interpreted. Some indications for performing an ECG include the following:
ECGs can be recorded as short intermittent tracings or continuous ECG monitoring. Continuous monitoring is used for critically ill patients, patients undergoing general anesthesia, [ 18 ] [ 17 ] and patients who have an infrequently occurring cardiac arrhythmia that would unlikely be seen on a conventional ten-second ECG. Continuous monitoring can be conducted by using Holter monitors , internal and external defibrillators and pacemakers , and/or biotelemetry . [ 19 ]
For adults, evidence does not support the use of ECGs among those without symptoms or at low risk of cardiovascular disease as an effort for prevention. [ 20 ] [ 21 ] [ 22 ] This is because an ECG may falsely indicate the existence of a problem, leading to misdiagnosis , the recommendation of invasive procedures, and overtreatment . However, persons employed in certain critical occupations, such as aircraft pilots, [ 23 ] may be required to have an ECG as part of their routine health evaluations. Hypertrophic cardiomyopathy screening may also be considered in adolescents as part of a sports physical out of concern for sudden cardiac death . [ 24 ]
Mechanical cardiographs (apex cardiogram), developed in the 19th century, recorded heart movements by transmitting heart or chest wall motions to a spring and air chamber system. A writing lever traced these movements onto a smoked rotating cylinder, producing a cardiogram. Their accuracy was limited, as they captured all body movements, introducing errors. [ 25 ]
Modern day electrocardiograms are recorded by machines that consist of a set of electrodes connected to a central unit. [ 26 ]
In the late 19th century, scientists discovered the heart’s electrical activity, leading to the electrocardiograph’s development. Willem Einthoven ’s 1903 string galvanometer enabled precise measurement of these signals, revolutionizing cardiography. He received the 1924 Nobel Prize for this work.
Early ECG machines were constructed with analog electronics , where the signal drove a motor to print out the signal onto paper. Today, electrocardiographs use analog-to-digital converters to convert the electrical activity of the heart to a digital signal . Many ECG machines are now portable and commonly include a screen, keyboard, and printer on a small wheeled cart. Recent advancements in electrocardiography include developing even smaller devices for inclusion in fitness trackers and smart watches . [ 27 ] These smaller devices often rely on only two electrodes to deliver a single lead I. [ 28 ] Portable twelve-lead devices powered by batteries are also available.
Recording an ECG is a safe and painless procedure. [ 29 ] The machines are powered by mains power but they are designed with several safety features including an earthed (ground) lead.
Other features include:
Most modern ECG machines include automated interpretation algorithms . This analysis calculates features such as the PR interval , QT interval , corrected QT (QTc) interval , PR axis, QRS axis, rhythm and more. The results from these automated algorithms are considered "preliminary" until verified and/or modified by expert interpretation. Despite recent advances, computer misinterpretation remains a significant problem and can result in clinical mismanagement. [ 30 ]
Besides the standard electrocardiograph machine, there are other devices that can record ECG signals. Portable devices have existed since the Holter monitor was introduced in 1962.
Traditionally, these monitors have used electrodes with patches on the skin to record the ECG, but new devices can stick to the chest as a single patch without need for wires, developed by Zio (Zio XT), TZ Medical (Trident), Philips (BioTel) and BardyDx (CAM) among many others.
Implantable devices such as the artificial cardiac pacemaker and implantable cardioverter-defibrillator are capable of measuring a "far field" signal between the leads in the heart and the implanted battery/generator that resembles an ECG signal (technically, the signal recorded in the heart is called an electrogram , which is interpreted differently).
The development of the Holter monitor led to the creation of the implantable loop recorder , which performs the same function but is an implantable device with batteries that last for years.
Additionally, there are available various Arduino kits with ECG sensor modules and smartwatch devices that are capable of recording an ECG signal as well, such as with the 4th generation Apple Watch (2018), Samsung Galaxy Watch 4 (2021) and newer devices.
Electrodes are the actual conductive pads attached to the body surface. [ 32 ] Any pair of electrodes can measure the electrical potential difference between the two corresponding locations of attachment. Such a pair forms a lead . However, "leads" can also be formed between a physical electrode and a virtual electrode , which is the average of numerous leads. All clinical ECGs use Wilson's central terminal ( WCT ) as the virtual electrode from which the precordial leads are measured, whose potential is defined as the average potential measured by the three standard limb leads. [ 33 ]
Commonly, 10 electrodes attached to the body are used to form 12 ECG leads, with each lead measuring a specific electrical potential difference. [ 34 ]
Leads are broken down into three types: limb; augmented limb; and precordial or chest. The 12-lead ECG has a total of three limb leads and three augmented limb leads arranged like spokes of a wheel in the coronal plane (vertical), and six precordial leads or chest leads that lie on the perpendicular transverse plane (horizontal). [ 35 ]
Electrodes should be placed in standard positions, with 'left' or 'right' referring to anatomical directions, being the patient's left or right. Exceptions due to emergency or other issues should be recorded to avoid erroneous analysis. [ 36 ]
The 12 standard ECG leads and electrodes are listed below. [ 37 ] All leads are effectively bipolar, with one positive and one negative electrode; the term "unipolar" is not true, nor useful. [ 33 ]
Two types of electrodes in common use are a flat paper-thin sticker and a self-adhesive circular pad.
The former are typically used in a single ECG recording while the latter are for continuous recordings as they stick longer.
Each electrode consists of an electrically conductive electrolyte gel and a silver/silver chloride conductor. [ 38 ] The gel typically contains potassium chloride – sometimes silver chloride as well – to permit electron conduction from the skin to the wire and to the electrocardiogram. [ 39 ]
The virtual electrode is used to obtain useful measurements from the precordial leads, and also allows the creation of the augmented limb leads.
The virtual electrode is known as Wilson's Central Terminal ( WCT ). For the precordial leads, WCT is formed by averaging the three standard limb leads (I, II, and III):
WCT is therefore a virtual electrode which sits slightly posteriorly to the heart. It is a useful point, from which the electrical potential of the precordial leads is measured. [ 33 ]
WCT used to be used as a reference for the virtual limb leads, however use in this way produced leads with very small amplitudes. Goldberger's modification is now used to produce each augmented limb lead, aVF, aVR, and aVL, which produces 50% larger amplitude leads than the standard WCT. Goldberger's WCT is formed according to the following: [ 33 ]
In a 12-lead ECG, all leads except the limb leads are assumed to be unipolar (aVR, aVL, aVF, V 1 , V 2 , V 3 , V 4 , V 5 , and V 6 ).
The measurement of a voltage requires two contacts and so, electrically, the unipolar leads are measured from the common lead (negative) and the unipolar lead (positive).
This averaging for the common lead and the abstract unipolar lead concept makes for a more challenging understanding and is complicated by sloppy usage of "lead" and "electrode".
In fact, instead of being a constant reference, V W has a value that fluctuates throughout the heart cycle. It also does not truly represent the center-of-heart potential due to the body parts the signals travel through. [ 40 ] Because voltage is by definition a bipolar measurement between two points, describing an electrocardiographic lead as "unipolar" makes little sense electrically and should be avoided. The American Heart Association states "All leads are effectively 'bipolar,' and the term 'unipolar' in description of the augmented limb leads and the precordial leads lacks precision." [ 41 ]
Leads I, II and III are called the limb leads . The electrodes that form these signals are located on the limbs – one on each arm and one on the left leg. [ 42 ] [ 43 ] The limb leads form the points of what is known as Einthoven's triangle . [ 44 ]
Leads aVR, aVL, and aVF are the augmented limb leads . They are derived from the same three electrodes as leads I, II, and III, but they use Goldberger's central terminal as their negative pole. Goldberger's central terminal is a combination of inputs from two limb electrodes, with a different combination for each augmented lead. It is referred to immediately below as "the negative pole".
Together with leads I, II, and III, augmented limb leads aVR, aVL, and aVF form the basis of the hexaxial reference system , which is used to calculate the heart's electrical axis in the frontal plane. [ 45 ]
Older versions of the nodes (VR, VL, VF) use Wilson's central terminal as the negative pole, but the amplitude is too small for the thick lines of old ECG machines. The Goldberger terminals scale up (augments) the Wilson results by 50%, at the cost of sacrificing physical correctness by not having the same negative pole for all three. [ 46 ]
The precordial leads lie in the transverse (horizontal) plane, perpendicular to the other six leads. The six precordial electrodes act as the positive poles for the six corresponding precordial leads: (V 1 , V 2 , V 3 , V 4 , V 5 , and V 6 ). Wilson's central terminal is used as the negative pole. Recently, unipolar precordial leads have been used to create bipolar precordial leads that explore the right to left axis in the horizontal plane. [ 47 ]
Additional electrodes may rarely be placed to generate other leads for specific diagnostic purposes. Right-sided precordial leads may be used to better study pathology of the right ventricle or for dextrocardia (and are denoted with an R (e.g., V 5R ). Posterior leads (V 7 to V 9 ) may be used to demonstrate the presence of a posterior myocardial infarction. The Lewis lead or S5-lead (requiring an electrode at the right sternal border in the second intercostal space) can be used to better detect atrial activity in relation to that of the ventricles. [ 48 ]
An esophageal lead can be inserted to a part of the esophagus where the distance to the posterior wall of the left atrium is only approximately 5–6 mm (remaining constant in people of different age and weight). [ 49 ] An esophageal lead avails for a more accurate differentiation between certain cardiac arrhythmias, particularly atrial flutter , AV nodal reentrant tachycardia and orthodromic atrioventricular reentrant tachycardia . [ 50 ] It can also evaluate the risk in people with Wolff-Parkinson-White syndrome , as well as terminate supraventricular tachycardia caused by re-entry . [ 50 ]
An intracardiac electrogram (ICEG) is essentially an ECG with some added intracardiac leads (that is, inside the heart). The standard ECG leads (external leads) are I, II, III, aVL, V 1 , and V 6 . Two to four intracardiac leads are added via cardiac catheterization. The word "electrogram" (EGM) without further specification usually means an intracardiac electrogram. [ 51 ]
A standard 12-lead ECG report (an electrocardiograph) shows a 2.5 second tracing of each of the twelve leads. The tracings are most commonly arranged in a grid of four columns and three rows. The first column is the limb leads (I, II, and III), the second column is the augmented limb leads (aVR, aVL, and aVF), and the last two columns are the precordial leads (V 1 to V 6 ).
Additionally, a rhythm strip may be included as a fourth or fifth row. [ 45 ]
The timing across the page is continuous and notes tracings of the 12 leads for the same time period.
In other words, if the output were traced by needles on paper, each row would switch which leads as the paper is pulled under the needle.
For example, the top row would first trace lead I, then switch to lead aVR, then switch to V 1 , and then switch to V 4 , and so none of these four tracings of the leads are from the same time period as they are traced in sequence through time. [ 52 ]
Each of the 12 ECG leads records the electrical activity of the heart from a different angle, and therefore align with different anatomical areas of the heart. Two leads that look at neighboring anatomical areas are said to be contiguous . [ 45 ]
In addition, any two precordial leads next to one another are considered to be contiguous. For example, though V 4 is an anterior lead and V 5 is a lateral lead, they are contiguous because they are next to one another.
The study of the conduction system of the heart is called cardiac electrophysiology (EP). An EP study is performed via a right-sided cardiac catheterization : a wire with an electrode at its tip is inserted into the right heart chambers from a peripheral vein, and placed in various positions in close proximity to the conduction system so that the electrical activity of that system can be recorded. [ citation needed ]
Standard catheter positions for an EP study include "high right atrium" or hRA near the sinus node , a "His" across the septal wall of the tricuspid valve to measure bundle of His , a "coronary sinus" into the coronary sinus , and a "right ventricle" in the apex of the right ventricle. [ 53 ]
Interpretation of the ECG is fundamentally about understanding the electrical conduction system of the heart .
Normal conduction starts and propagates in a predictable pattern, and deviation from this pattern can be a normal variation or be pathological .
An ECG does not equate with mechanical pumping activity of the heart; for example, pulseless electrical activity produces an ECG that should pump blood but no pulses are felt (and constitutes a medical emergency and CPR should be performed). Ventricular fibrillation produces an ECG but is too dysfunctional to produce a life-sustaining cardiac output. Certain rhythms are known to have good cardiac output and some are known to have bad cardiac output.
Ultimately, an echocardiogram or other anatomical imaging modality is useful in assessing the mechanical function of the heart. [ 54 ]
Like all medical tests, what constitutes "normal" is based on population studies . The heartrate range of between 60 and 100 beats per minute (bpm) is considered normal since data shows this to be the usual resting heart rate. [ 55 ]
Interpretation of the ECG is ultimately that of pattern recognition.
In order to understand the patterns found, it is helpful to understand the theory of what ECGs represent.
The theory is rooted in electromagnetics and boils down to the four following points: [ 56 ]
Thus, the overall direction of depolarization and repolarization produces positive or negative deflection on each lead's trace.
For example, depolarizing from right to left would produce a positive deflection in lead I because the two vectors point in the same direction.
In contrast, that same depolarization would produce minimal deflection in V 1 and V 2 because the vectors are perpendicular, and this phenomenon is called isoelectric.
Normal rhythm produces four entities – a P wave , a QRS complex , a T wave , and a U wave – that each have a fairly unique pattern.
Changes in the structure of the heart and its surroundings (including blood composition) change the patterns of these four entities.
The U wave is not typically seen and its absence is generally ignored. Atrial repolarization is typically hidden in the much more prominent QRS complex and normally cannot be seen without additional, specialized electrodes.
ECGs are normally printed on a grid.
The horizontal axis represents time and the vertical axis represents voltage.
The standard values on this grid are shown in the adjacent image at 25mm/sec (or 40ms per mm): [ 57 ]
The "large" box is represented by a heavier line weight than the small boxes.
The standard printing speed in the United States is 25 mm per sec (5 big boxes per second), but in other countries it can be 50 mm per sec.
Faster speeds such as 100 and 200 mm per sec are used during electrophysiology studies.
Not all aspects of an ECG rely on precise recordings or having a known scaling of amplitude or time.
For example, determining if the tracing is a sinus rhythm only requires feature recognition and matching, and not measurement of amplitudes or times (i.e., the scale of the grids are irrelevant).
An example to the contrary, the voltage requirements of left ventricular hypertrophy require knowing the grid scale.
In a normal heart, the heart rate is the rate at which the sinoatrial node depolarizes since it is the source of depolarization of the heart.
Heart rate, like other vital signs such as blood pressure and respiratory rate, change with age.
In adults, a normal heart rate is between 60 and 100 bpm (normocardic), whereas it is higher in children. [ 58 ] A heart rate below normal is called " bradycardia " (<60 in adults) and above normal is called " tachycardia " (>100 in adults).
A complication of this is when the atria and ventricles are not in synchrony and the "heart rate" must be specified as atrial or ventricular (e.g., the ventricular rate in ventricular fibrillation is 300–600 bpm, whereas the atrial rate can be normal [60–100] or faster [100–150]). [ citation needed ]
In normal resting hearts, the physiologic rhythm of the heart is normal sinus rhythm (NSR).
Normal sinus rhythm produces the prototypical pattern of P wave, QRS complex, and T wave.
Generally, deviation from normal sinus rhythm is considered a cardiac arrhythmia .
Thus, the first question in interpreting an ECG is whether or not there is a sinus rhythm.
A criterion for sinus rhythm is that P waves and QRS complexes appear 1-to-1, thus implying that the P wave causes the QRS complex. [ 52 ]
Once sinus rhythm is established, or not, the second question is the rate.
For a sinus rhythm, this is either the rate of P waves or QRS complexes since they are 1-to-1.
If the rate is too fast, then it is sinus tachycardia , and if it is too slow, then it is sinus bradycardia .
If it is not a sinus rhythm, then determining the rhythm is necessary before proceeding with further interpretation.
Some arrhythmias with characteristic findings:
Determination of rate and rhythm is necessary in order to make sense of further interpretation.
The heart has several axes, but the most common by far is the axis of the QRS complex (references to "the axis" imply the QRS axis).
Each axis can be computationally determined to result in a number representing degrees of deviation from zero, or it can be categorized into a few types. [ 59 ]
The QRS axis is the general direction of the ventricular depolarization wavefront (or mean electrical vector) in the frontal plane.
It is often sufficient to classify the axis as one of three types: normal, left deviated, or right deviated.
Population data shows that a normal QRS axis is from −30° to 105°, with 0° being along lead I and positive being inferior and negative being superior (best understood graphically as the hexaxial reference system ). [ 60 ] Beyond +105° is right axis deviation and beyond −30° is left axis deviation (the third quadrant of −90° to −180° is very rare and is an indeterminate axis).
A shortcut for determining if the QRS axis is normal is if the QRS complex is mostly positive in lead I and lead II (or lead I and aVF if +90° is the upper limit of normal). [ 61 ]
The normal QRS axis is generally down and to the left , following the anatomical orientation of the heart within the chest. An abnormal axis suggests a change in the physical shape and orientation of the heart or a defect in its conduction system that causes the ventricles to depolarize in an abnormal way. [ 52 ]
The extent of a normal axis can be +90° or 105° depending on the source.
All of the waves on an ECG tracing and the intervals between them have a predictable time duration, a range of acceptable amplitudes ( voltages ), and a typical morphology. Any deviation from the normal tracing is potentially pathological and therefore of clinical significance. [ 62 ]
For ease of measuring the amplitudes and intervals, an ECG is printed on graph paper at a standard scale: each 1 mm (one small box on the standard 25mm/s ECG paper) represents 40 milliseconds of time on the x-axis, and 0.1 millivolts on the y-axis. [ 63 ]
In electrocardiogram (ECG) signal processing, Time-Frequency Analysis (TFA) is an important technique used to reveal how the frequency characteristics of ECG signals change over time, especially in non-stationary signals such as arrhythmias or transient cardiac events.
Common Methods for Time-Frequency Analysis
Provides instantaneous frequency distribution.
Steps for Time-Frequency Analysis
Step1: Preprocessing
Step2: Select an Appropriate TFA Method
Step3: Compute the Time-Frequency Spectrum
Step4: Feature Extraction
Step5: Pattern Recognition or Diagnosis
Application Scenarios
Heart Rate Variability Analysis (HRV):
Atrial Fibrillation Detection:
Ventricular Fibrillation Analysis:
The animation shown to the right illustrates how the path of electrical conduction gives rise to the ECG waves in the limb leads.
What is green zone ?
Recall that a positive current (as created by depolarization of cardiac cells) traveling towards the positive electrode and away from the negative electrode creates a positive deflection on the ECG. Likewise, a positive current traveling away from the positive electrode and towards the negative electrode creates a negative deflection on the ECG. [ 66 ] [ 67 ] The red arrow represents the overall direction of travel of the depolarization. The magnitude of the red arrow is proportional to the amount of tissue being depolarized at that instance. The red arrow is simultaneously shown on the axis of each of the 3 limb leads. Both the direction and the magnitude of the red arrow's projection onto the axis of each limb lead is shown with blue arrows. Then, the direction and magnitude of the blue arrows are what theoretically determine the deflections on the ECG. For example, as a blue arrow on the axis for Lead I moves from the negative electrode, to the right, towards the positive electrode, the ECG line rises, creating an upward wave. As the blue arrow on the axis for Lead I moves to the left, a downward wave is created. The greater the magnitude of the blue arrow, the greater the deflection on the ECG for that particular limb lead. [ 68 ]
Frames 1–3 depict the depolarization being generated in and spreading through the sinoatrial node . The SA node is too small for its depolarization to be detected on most ECGs. Frames 4–10 depict the depolarization traveling through the atria, towards the atrioventricular node . During frame 7, the depolarization is traveling through the largest amount of tissue in the atria, which creates the highest point in the P wave. Frames 11–12 depict the depolarization traveling through the AV node. Like the SA node, the AV node is too small for the depolarization of its tissue to be detected on most ECGs. This creates the flat PR segment. [ 69 ]
Frame 13 depicts an interesting phenomenon in an over-simplified fashion. It depicts the depolarization as it starts to travel down the interventricular septum, through the bundle of His and bundle branches . After the Bundle of His, the conduction system splits into the left bundle branch and the right bundle branch. Both branches conduct action potentials at about 1 m/s. However, the action potential starts traveling down the left bundle branch about 5 milliseconds before it starts traveling down the right bundle branch, as depicted by frame 13. This causes the depolarization of the interventricular septum tissue to spread from left to right, as depicted by the red arrow in frame 14. In some cases, this gives rise to a negative deflection after the PR interval, creating a Q wave such as the one seen in lead I in the animation to the right. Depending on the mean electrical axis of the heart, this phenomenon can result in a Q wave in lead II as well. [ 70 ] [ 71 ]
Following depolarization of the interventricular septum, the depolarization travels towards the apex of the heart. This is depicted by frames 15–17 and results in a positive deflection on all three limb leads, which creates the R wave. Frames 18–21 then depict the depolarization as it travels throughout both ventricles from the apex of the heart, following the action potential in the Purkinje fibers . This phenomenon creates a negative deflection in all three limb leads, forming the S wave on the ECG. Repolarization of the atria occurs at the same time as the generation of the QRS complex, but it is not detected by the ECG since the tissue mass of the ventricles is so much larger than that of the atria. Ventricular contraction occurs between ventricular depolarization and repolarization. During this time, there is no movement of charge, so no deflection is created on the ECG. This results in the flat ST segment after the S wave. [ 72 ]
Frames 24–28 in the animation depict repolarization of the ventricles. The epicardium is the first layer of the ventricles to repolarize, followed by the myocardium. The endocardium is the last layer to repolarize. The plateau phase of depolarization has been shown to last longer in endocardial cells than in epicardial cells. This causes repolarization to start from the apex of the heart and move upwards. Since repolarization is the spread of negative current as membrane potentials decrease back down to the resting membrane potential, the red arrow in the animation is pointing in the direction opposite of the repolarization. This therefore creates a positive deflection in the ECG, and creates the T wave. [ 73 ]
Ischemia or non-ST elevation myocardial infarctions (non-STEMIs) may manifest as ST depression or inversion of T waves . It may also affect the high frequency band of the QRS .
ST elevation myocardial infarctions (STEMIs) have different characteristic ECG findings based on the amount of time elapsed since the MI first occurred. The earliest sign is hyperacute T waves, peaked T waves due to local hyperkalemia in ischemic myocardium. This then progresses over a period of minutes to elevations of the ST segment by at least 1 mm. Over a period of hours, a pathologic Q wave may appear and the T wave will invert. Over a period of days the ST elevation will resolve. Pathologic Q waves generally will remain permanently. [ 74 ]
The coronary artery that has been occluded can be identified in an STEMI based on the location of ST elevation. The left anterior descending (LAD) artery supplies the anterior wall of the heart, and therefore causes ST elevations in anterior leads (V 1 and V 2 ). The LCx supplies the lateral aspect of the heart and therefore causes ST elevations in lateral leads (I, aVL and V 6 ). The right coronary artery (RCA) usually supplies the inferior aspect of the heart, and therefore causes ST elevations in inferior leads (II, III and aVF). [ 75 ]
An ECG tracing is affected by patient motion. Some rhythmic motions (such as shivering or tremors ) can create the illusion of cardiac arrhythmia. [ 76 ] Artifacts are distorted signals caused by a secondary internal or external sources, such as muscle movement or interference from an electrical device. [ 77 ] [ 78 ]
Distortion poses significant challenges to healthcare providers, [ 77 ] who employ various techniques [ 79 ] and strategies to safely recognize [ 80 ] these false signals. [ medical citation needed ] Accurately separating the ECG artifact from the true ECG signal can have a significant impact on patient outcomes and legal liabilities . [ 81 ] [ unreliable medical source? ]
Improper lead placement (for example, reversing two of the limb leads) has been estimated to occur in 0.4% to 4% of all ECG recordings, [ 82 ] and has resulted in improper diagnosis and treatment including unnecessary use of thrombolytic therapy. [ 83 ] [ 84 ]
Whitbread, consultant nurse and paramedic, suggests ten rules of the normal ECG, deviation from which is likely to indicate pathology. [ 85 ] These have been added to, creating the 15 rules for 12-lead (and 15- or 18-lead) interpretation. [ 86 ]
Rule 1: All waves in aVR are negative.
Rule 2: The ST segment (J point) starts on the isoelectric line (except in V1 & V2 where it may be elevated by not greater than 1 mm).
Rule 3: The PR interval should be 0.12–0.2 seconds long.
Rule 4: The QRS complex should not exceed 0.11–0.12 seconds.
Rule 5: The QRS and T waves tend to have the same general direction in the limb leads.
Rule 6: The R wave in the precordial (chest) leads grows from V1 to at least V4 where it may or may not decline again.
Rule 7: The QRS is mainly upright in I and II.
Rule 8: The P wave is upright in I II and V2 to V6.
Rule 9: There is no Q wave or only a small q (<0.04 seconds in width) in I, II and V2 to V6.
Rule 10: The T wave is upright in I II and V2 to V6. The end of the T wave should not drop below the isoelectric baseline.
Rule 11: Does the deepest S wave in V1 plus the tallest R wave in V5 or V6 equal >35 mm?
Rule 12: Is there an Epsilon wave ?
Rule 13: Is there an J wave?
Rule 14: Is there a Delta wave ?
Rule 15: Are there any patterns representing an occlusive myocardial infarction (OMI)?
Numerous diagnoses and findings can be made based upon electrocardiography, and many are discussed above. Overall, the diagnoses are made based on the patterns. For example, an "irregularly irregular" QRS complex without P waves is the hallmark of atrial fibrillation ; however, other findings can be present as well, such as a bundle branch block that alters the shape of the QRS complexes. ECGs can be interpreted in isolation but should be applied – like all diagnostic tests – in the context of the patient. For example, an observation of peaked T waves is not sufficient to diagnose hyperkalemia; such a diagnosis should be verified by measuring the blood potassium level. Conversely, a discovery of hyperkalemia should be followed by an ECG for manifestations such as peaked T waves, widened QRS complexes, and loss of P waves. The following is an organized list of possible ECG-based diagnoses. [ 87 ]
Rhythm disturbances or arrhythmias: [ 88 ]
Heart block and conduction problems:
Electrolytes disturbances and intoxication:
Ischemia and infarction:
Structural:
Other phenomena:
The word is derived from the Greek electro , meaning related to electrical activity; kardia , meaning heart; and graph , meaning "to write". [ 101 ]
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https://en.wikipedia.org/wiki/Electrocardiography
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Electrocardiography in suspected myocardial infarction has the main purpose of detecting ischemia or acute coronary injury in emergency department populations coming for symptoms of myocardial infarction (MI). Also, it can distinguish clinically different types of myocardial infarction.
The standard 12 lead electrocardiogram (ECG) has several limitations. An ECG represents a brief sample in time. Because unstable ischemic syndromes have rapidly changing supply versus demand characteristics, a single ECG may not accurately represent the entire picture. [ 1 ] It is therefore desirable to obtain serial 12 lead ECGs, particularly if the first ECG is obtained during a pain-free episode. Alternatively, many emergency departments and chest pain centers use computers capable of continuous ST segment monitoring. [ 2 ] The standard 12 lead ECG also does not directly examine the right ventricle , and is relatively poor at examining the posterior basal and lateral walls of the left ventricle . In particular, acute myocardial infarction in the distribution of the circumflex artery is likely to produce a nondiagnostic ECG. [ 1 ] The use of additional ECG leads like right-sided leads V3R and V4R and posterior leads V7, V8, and V9 may improve sensitivity for right ventricular and posterior myocardial infarction. In spite of these limitations, the 12 lead ECG stands at the center of risk stratification for the patient with suspected acute myocardial infarction. Mistakes in interpretation are relatively common, and the failure to identify high risk features has a negative effect on the quality of patient care. [ 3 ]
The 12 lead ECG is used to classify MI patients into one of three groups: [ 4 ]
The 2018 European Society of Cardiology/American College of Cardiology Foundation/American Heart Association/World Health Federation Universal Definition of Myocardial Infarction for the ECG diagnosis of the ST segment elevation type of acute myocardial infarction require new ST elevation at J point of at least 1mm (0.1 mV) in two contiguous leads with the cut-points: ≥1 mm in all leads other than leads V2-V3. For leads V2-V3: ≥2 mm in men ≥40 years, ≥2.5 mm in men <40 years, or ≥1.5 mm in women regardless of age. This assumes usual calibration of 1mV/10mm. [ 5 ] These elevations must be present in anatomically contiguous leads. [ 4 ] (I, aVL, V5, V6 correspond to the lateral wall; V3-V4 correspond to the anterior wall ; V1-V2 correspond to the septal wall; II, III, aVF correspond to the inferior wall.) This criterion is problematic, however, as acute myocardial infarction is not the most common cause of ST segment elevation in chest pain patients. [ 6 ] Over 90% of healthy men have at least 1 mm (0.1 mV) of ST segment elevation in at least one precordial lead. [ 7 ] The clinician must therefore be well versed in recognizing the so-called ECG mimics of acute myocardial infarction, which include left ventricular hypertrophy , left bundle branch block , paced rhythm , early repolarization , pericarditis , hyperkalemia , and ventricular aneurysm . [ 7 ] [ 8 ] [ 9 ]
There are heavily researched clinical decision tools such as the TIMI Scores which help prognose and diagnose STEMI based on clinical data. For example, TIMI scores are frequently used to take advantage of EKG findings to prognose patients with MI symptoms. [ 10 ] Based on symptoms and electrocardiographic findings, practitioners can differentiate between unstable angina, NSTEMI and STEMI, normally in the emergency room setting. [ 11 ] Other calculators such as the GRACE [ 12 ] and HEART [ 13 ] scores, assess other major cardiac events using electrocardiogram findings, both predicting mortality rates for 6 months and 6 weeks, respectively. [ citation needed ]
Sometimes the earliest presentation of acute myocardial infarction is the hyperacute T wave, which is treated the same as ST segment elevation. [ 14 ] In practice this is rarely seen, because it only exists for 2–30 minutes after the onset of infarction. [ 15 ] Hyperacute T waves need to be distinguished from the peaked T waves associated with hyperkalemia . [ 16 ]
In the first few hours the ST segments usually begin to rise. [ 17 ] Pathological Q waves may appear within hours or may take greater than 24 hr. [ 17 ] The T wave will generally become inverted in the first 24 hours, as the ST elevation begins to resolve. [ 17 ]
Long term changes of ECG include persistent Q waves (in 90% of cases) and persistent inverted T waves. [ 17 ] Persistent ST elevation is rare except in the presence of a ventricular aneurysm . [ 17 ]
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https://en.wikipedia.org/wiki/Electrocardiography_in_myocardial_infarction
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Electrocochleography (abbreviated ECochG or ECOG ) is a technique of recording electrical potentials generated in the inner ear and auditory nerve in response to sound stimulation, using an electrode placed in the ear canal or tympanic membrane . [ 1 ] The test is performed by an otologist or audiologist with specialized training, and is used for detection of elevated inner ear pressure ( endolymphatic hydrops ) or for the testing and monitoring of inner ear and auditory nerve function during surgery. [ 2 ]
The most common clinical applications of electrocochleography include:
The basilar membrane and the hair cells of the cochlea function as a sharply tuned frequency analyzer. [ 3 ] Sound is transmitted to the inner ear via vibration of the tympanic membrane , leading to movement of the middle ear bones (malleus, incus, and stapes). Movement of the stapes on the oval window generates a pressure wave in the perilymph within the cochlea, causing the basilar membrane to vibrate. Sounds of different frequencies vibrate different parts of the basilar membrane, and the point of maximal vibration amplitude depends on the sound frequency. [ 4 ]
As the basilar membrane vibrates, the hair cells attached to this membrane are rhythmically pushed up against the tectorial membrane , bending the hair cell stereocilia . This opens mechanically gated ion channels on the hair cell, allowing influx of potassium (K + ) and calcium (Ca 2+ ) ions. The flow of ions generates an AC current through the hair cell surface, at the same frequency as the acoustic stimulus. This measurable AC voltage is called the cochlear microphonic (CM), which mimics the stimulus. The hair cells function as a transducer, converting the mechanical movement of the basilar membrane into electrical voltage, in a process requiring ATP from the stria vascularis as an energy source.
The depolarized hair cell releases neurotransmitters across a synapse to primary auditory neurons of the spiral ganglion . Upon reaching receptors on the postsynaptic spiral ganglion neurons, the neurotransmitters induce a postsynaptic potential or generator potential in the neuronal projections. When a certain threshold potential is reached, the spiral ganglion neuron fires an action potential, which enters the auditory processing pathway of the brain.
A resting endolymphatic potential of a normal cochlea is + 80 mV. There are at least 3 other potentials generated upon cochlear stimulation:
As described above, the cochlear microphonic (CM) is an alternating current (AC) voltage that mirrors the waveform of the acoustic stimulus. It is dominated by the outer hair cells of the organ of Corti. The magnitude of the recording is dependent on the proximity of the recording electrodes to the hair cells. The CM is proportional to the displacement of the basilar membrane. [ 4 ] A fourth potential, the auditory nerve neurophonic, is sometimes dissociated from the CM. The neurophonic represents the neural part (auditory nerve spikes) phased-locked to the stimulus and is similar to the Frequency following response . [ 5 ]
The summating potential (SP), first described by Tasaki et al. in 1954, represents the direct current (DC) response of the hair cells as they move in conjunction with the basilar membrane, [ 6 ] as well as the DC response from dendritic and axonal potentials of the auditory nerve. [ 7 ] The SP is the stimulus-related potential of the cochlea. Although historically it has been the least studied, renewed interest has surfaced due to changes in the SP reported in cases of endolymphatic hydrops or Ménière's disease.
The auditory nerve action potential, also called the compound action potential (CAP), is the most widely studied component in ECochG. The AP represents the summed response of the synchronous firing of the nerve fibers. It also appears as an AC voltage. The first and largest wave (N1) is identical to wave I of auditory brainstem response (ABR). Following this is N2, which is identical to wave II of the ABR. The magnitude of the action potential reflects the number of fibers that are firing. The latency of the AP is measured as the time between the onset and the peak of the N1 wave.
The CAP is considered to have low sensitivity to changes in stimulus polarity, in contrast to the CM which follows the polarity of the stimulation. As a result, researchers often use the sum (or difference) of responses to stimuli of alternating polarity to dissociate the CAP from CM.
ECochG can be performed with either invasive or non-invasive electrodes. Invasive electrodes, such as transtympanic (TT) needles, give clearer, more robust electrical responses (with larger amplitudes) since the electrodes are very close to the voltage generators. The needle is placed on the promontory wall of the middle ear and the round window. Non-invasive, or extratympanic (ET), electrodes have the advantage of not causing pain or discomfort to the patient. Unlike with invasive electrodes, there is no need for sedation, anesthesia, or medical supervision. The responses, however, are smaller in magnitude.
Auditory stimuli in the form of broadband clicks 100 microseconds in duration are used. The stimulus polarity can be rarefaction polarity, condensation polarity, or alternating polarity. Signals are recorded from a primary recording (non-inverted) electrode located in the ear canal, tympanic membrane, or promontory (depending on type of electrode used). Reference (inverting) electrodes can be placed on the contralateral earlobe, mastoid, or ear canal.
The signal is processed, including signal amplification (by as much as a factor 100000 for extratympanic electrode recordings), noise filtration, and signal averaging. A band-pass filter from 10 Hz to 1.5 kHz is often used.
The CM, SP, and AP are all used in the diagnosis of endolymphatic hydrops and Ménière's disease. In particular, abnormally high SP and a high SP:AP ratio are signs of Ménière's disease. An SP:AP ratio of 0.45 or greater is considered abnormal.
The CM was first discovered in 1930 by Ernest Wever and Charles Bray in cats. [ 8 ] Wever and Bray mistakenly concluded that this recording was generated by the auditory nerve. They named the discovery the "Wever-Bray effect". Hallowell Davis and A.J. Derbyshire from Harvard replicated the study and concluded that the waves were in fact cochlear origin and not from the auditory nerve. [ 9 ]
Fromm et al. were the first investigators to employ the ECochG technique in humans by inserting a wire electrode through the tympanic membrane and recording the CM from the niche of the round window and cochlear promontory. Their first measurement of the CM in humans was in 1935. [ 10 ] They also discovered the N1, N2, and N3 waves following the CM, but it was Tasaki who identified these waves as auditory nerve action potentials.
Fisch and Ruben were the first to record the compound action potentials from both the round window and the eighth cranial nerve (CN VIII) in cats and mice. [ 11 ] Ruben was also the first person to use CM and AP clinically.
The summating potential, a stimulus-related hair cell potential, was first described by Tasaki and colleagues in 1954. [ 6 ] Ernest J. Moore was the first investigator to record the CM from surface electrodes. In 1971, Moore conducted five experiments in which he recorded CM and AP from 38 human subjects using surface electrodes. The purpose of the experiment was to establish the validity of the responses and to develop an artifact-free earphone system. [ 12 ] Unfortunately, bulk of his work was never published.
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https://en.wikipedia.org/wiki/Electrocochleography
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Electrocorticography ( ECoG ), a type of intracranial electroencephalography ( iEEG ), is a type of electrophysiological monitoring that uses electrodes placed directly on the exposed surface of the brain to record electrical activity from the cerebral cortex . In contrast, conventional electroencephalography (EEG) electrodes monitor this activity from outside the skull. ECoG may be performed either in the operating room during surgery (intraoperative ECoG) or outside of surgery (extraoperative ECoG). Because a craniotomy (a surgical incision into the skull) is required to implant the electrode grid, ECoG is an invasive procedure.
ECoG was pioneered in the early 1950s by Wilder Penfield and Herbert Jasper , neurosurgeons at the Montreal Neurological Institute . [ 1 ] The two developed ECoG as part of their groundbreaking Montreal procedure , a surgical protocol used to treat patients with severe epilepsy . The cortical potentials recorded by ECoG were used to identify epileptogenic zones – regions of the cortex that generate epileptic seizures . These zones would then be surgically removed from the cortex during resectioning, thus destroying the brain tissue where epileptic seizures had originated. Penfield and Jasper also used electrical stimulation during ECoG recordings in patients undergoing epilepsy surgery under local anesthesia . [ 2 ] This procedure was used to explore the functional anatomy of the brain, mapping speech areas and identifying the somatosensory and somatomotor cortex areas to be excluded from surgical removal.
A doctor named Robert Galbraith Heath was also an early researcher of the brain at the Tulane University School of Medicine . [ 3 ] [ 4 ]
ECoG signals are composed of synchronized postsynaptic potentials ( local field potentials ), recorded directly from the exposed surface of the cortex. The potentials occur primarily in cortical pyramidal cells , and thus must be conducted through several layers of the cerebral cortex, cerebrospinal fluid (CSF), pia mater , and arachnoid mater before reaching subdural recording electrodes placed just below the dura mater (outer cranial membrane). However, to reach the scalp electrodes of a conventional electroencephalogram (EEG), electrical signals must also be conducted through the skull , where potentials rapidly attenuate due to the low conductivity of bone . For this reason, the spatial resolution of ECoG is much higher than EEG, a critical imaging advantage for presurgical planning. [ 5 ] ECoG offers a temporal resolution of approximately 5 ms and spatial resolution as low as 1-100 μm. [ 6 ]
Using depth electrodes, the local field potential gives a measure of a neural population in a sphere with a radius of 0.5–3 mm around the tip of the electrode. [ 7 ] With a sufficiently high sampling rate (more than about 10 kHz), depth electrodes can also measure action potentials . [ 8 ] In which case the spatial resolution is down to individual neurons, and the field of view of an individual electrode is approximately 0.05–0.35 mm. [ 7 ]
The ECoG recording is performed from electrodes placed on the exposed cortex. In order to access the cortex, a surgeon must first perform a craniotomy, removing a part of the skull to expose the brain surface. This procedure may be performed either under general anesthesia or under local anesthesia if patient interaction is required for functional cortical mapping. Electrodes are then surgically implanted on the surface of the cortex, with placement guided by the results of preoperative EEG and magnetic resonance imaging (MRI). Electrodes may either be placed outside the dura mater (epidural) or under the dura mater (subdural). ECoG electrode arrays typically consist of sixteen sterile, disposable stainless steel, carbon tip, platinum, Platinum-iridium alloy or gold ball electrodes, each mounted on a ball and socket joint for ease in positioning. These electrodes are attached to an overlying frame in a "crown" or "halo" configuration. [ 9 ] Subdural strip and grid electrodes are also widely used in various dimensions, having anywhere from 4 to 256 [ 10 ] electrode contacts. The grids are transparent, flexible, and numbered at each electrode contact. Standard spacing between grid electrodes is 1 cm; individual electrodes are typically 5 mm in diameter. The electrodes sit lightly on the cortical surface, and are designed with enough flexibility to ensure that normal movements of the brain do not cause injury. A key advantage of strip and grid electrode arrays is that they may be slid underneath the dura mater into cortical regions not exposed by the craniotomy. Strip electrodes and crown arrays may be used in any combination desired. Depth electrodes may also be used to record activity from deeper structures such as the hippocampus .
Direct cortical electrical stimulation (DCES), also known as cortical stimulation mapping , is frequently performed in concurrence with ECoG recording for functional mapping of the cortex and identification of critical cortical structures. [ 9 ] When using a crown configuration, a handheld wand bipolar stimulator may be used at any location along the electrode array. However, when using a subdural strip, stimulation must be applied between pairs of adjacent electrodes due to the nonconductive material connecting the electrodes on the grid. Electrical stimulating currents applied to the cortex are relatively low, between 2 and 4 mA for somatosensory stimulation, and near 15 mA for cognitive stimulation. [ 9 ] The stimulation frequency is usually 60 Hz in North America and 50 Hz in Europe, and any charge density more than 150 μC/cm2 causes tissue damage. [ 11 ] [ 12 ]
The functions most commonly mapped through DCES are primary motor, primary sensory, and language. The patient must be alert and interactive for mapping procedures, though patient involvement varies with each mapping procedure. Language mapping may involve naming, reading aloud, repetition, and oral comprehension; somatosensory mapping requires that the patient describe sensations experienced across the face and extremities as the surgeon stimulates different cortical regions. [ 9 ]
Since its development in the 1950s, ECoG has been used to localize epileptogenic zones during presurgical planning, map out cortical functions, and to predict the success of epileptic surgical resectioning. ECoG offers several advantages over alternative diagnostic modalities:
Limitations of ECoG include:
Epilepsy is currently ranked as the third most commonly diagnosed neurological disorder, afflicting approximately 2.5 million people in the United States alone. [ 13 ] Epileptic seizures are chronic and unrelated to any immediately treatable causes, such as toxins or infectious diseases, and may vary widely based on etiology, clinical symptoms, and site of origin within the brain. For patients with intractable epilepsy – epilepsy that is unresponsive to anticonvulsants – surgical treatment may be a viable treatment option. Partial epilepsy [ 14 ] is the common intractable epilepsy and the partial seizure is difficult to locate.Treatment for such epilepsy is limited to attachment of vagus nerve stimulator. Epilepsy surgery is the cure for partial epilepsy provided that the brain region generating seizure is carefully and accurately removed.
Before a patient can be identified as a candidate for resectioning surgery, MRI must be performed to demonstrate the presence of a structural lesion within the cortex, supported by EEG evidence of epileptogenic tissue. [ 2 ] Once a lesion has been identified, ECoG may be performed to determine the location and extent of the lesion and surrounding irritative region. The scalp EEG, while a valuable diagnostic tool, lacks the precision necessary to localize the epileptogenic region. ECoG is considered to be the gold standard for assessing neuronal activity in patients with epilepsy, and is widely used for presurgical planning to guide surgical resection of the lesion and epileptogenic zone. [ 15 ] [ 16 ] The success of the surgery depends on accurate localization and removal of the epileptogenic zone. ECoG data is assessed with regard to ictal spike activity – "diffuse fast wave activity" recorded during a seizure – and interictal epileptiform activity (IEA), brief bursts of neuronal activity recorded between epileptic events. ECoG is also performed following the resectioning surgery to detect any remaining epileptiform activity, and to determine the success of the surgery. Residual spikes on the ECoG, unaltered by the resection, indicate poor seizure control, and incomplete neutralization of the epileptogenic cortical zone. Additional surgery may be necessary to completely eradicate seizure activity. Extraoperative ECoG is also used to localize functionally-important areas (also known as eloquent cortex) to be preserved during epilepsy surgery. [ 17 ] Motor, sensory, cognitive tasks during extraoperative ECoG are reported to increase the amplitude of high-frequency activity at 70–110 Hz in areas involved in execution of given tasks. [ 17 ] [ 18 ] [ 19 ] Task-related high-frequency activity can animate 'when' and 'where' cerebral cortex is activated and inhibited in a 4D manner with a temporal resolution of 10 milliseconds or below and a spatial resolution of 10 mm or below. [ 18 ] [ 19 ]
The objective of the resectioning surgery is to remove the epileptogenic tissue without causing unacceptable neurological consequences. In addition to identifying and localizing the extent of epileptogenic zones, ECoG used in conjunction with DCES is also a valuable tool for functional cortical mapping . It is vital to precisely localize critical brain structures, identifying which regions the surgeon must spare during resectioning (the " eloquent cortex ") in order to preserve sensory processing, motor coordination, and speech. Functional mapping requires that the patient be able to interact with the surgeon, and thus is performed under local rather than general anesthesia. Electrical stimulation using cortical and acute depth electrodes is used to probe distinct regions of the cortex in order to identify centers of speech, somatosensory integration, and somatomotor processing. During the resectioning surgery, intraoperative ECoG may also be performed to monitor the epileptic activity of the tissue and ensure that the entire epileptogenic zone is resectioned.
Although the use of extraoperative and intraoperative ECoG in resectioning surgery has been an accepted clinical practice for several decades, recent studies have shown that the usefulness of this technique may vary based on the type of epilepsy a patient exhibits. Kuruvilla and Flink reported that while intraoperative ECoG plays a critical role in tailored temporal lobectomies, in multiple subpial transections (MST), and in the removal of malformations of cortical development (MCDs), it has been found impractical in standard resection of medial temporal lobe epilepsy (TLE) with MRI evidence of mesial temporal sclerosis (MTS). [ 2 ] A study performed by Wennberg, Quesney, and Rasmussen demonstrated the presurgical significance of ECoG in frontal lobe epilepsy (FLE) cases. [ 20 ]
ECoG has recently emerged as a promising recording technique for use in brain-computer interfaces (BCI). [ 21 ] BCIs are direct neural interfaces that provide control of prosthetic, electronic, or communication devices via direct use of the individual's brain signals. Brain signals may be recorded either invasively, with recording devices implanted directly into the cortex, or noninvasively, using EEG scalp electrodes. ECoG serves to provide a partially invasive compromise between the two modalities – while ECoG does not penetrate the blood–brain barrier like invasive recording devices, it features a higher spatial resolution and higher signal-to-noise ratio than EEG. [ 21 ] ECoG has gained attention recently for decoding imagined speech or music, which could lead to "literal" BCIs [ 22 ] in which users simply imagine words, sentences, or music that the BCI can directly interpret. [ 23 ] [ 24 ]
In addition to clinical applications to localize functional regions to support neurosurgery, real-time functional brain mapping with ECoG has gained attention to support research into fundamental questions in neuroscience. For example, a 2017 study explored regions within face and color processing areas and found that these subregions made highly specific contributions to different aspects of vision. [ 25 ] Another study found that high-frequency activity from 70 to 200 Hz reflected processes associated with both transient and sustained decision-making. [ 26 ] Other work based on ECoG presented a new approach to interpreting brain activity, suggesting that both power and phase jointly influence instantaneous voltage potential, which directly regulates cortical excitability. [ 27 ] Like the work toward decoding imagined speech and music, these research directions involving real-time functional brain mapping also have implications for clinical practice, including both neurosurgery and BCI systems. The system that was used in most of these real-time functional mapping publications, "CortiQ" . has been used for both research and clinical applications.
The electrocorticogram is still considered to be the " gold standard " for defining epileptogenic zones; however, this procedure is risky and highly invasive. Recent studies have explored the development of a noninvasive cortical imaging technique for presurgical planning that may provide similar information and resolution of the invasive ECoG.
In one novel approach, Lei Ding et al. [ 28 ] seek to integrate the information provided by a structural MRI and scalp EEG to provide a noninvasive alternative to ECoG. This study investigated a high-resolution subspace source localization approach, FINE (first principle vectors) to image the locations and estimate the extents of current sources from the scalp EEG. A thresholding technique was applied to the resulting tomography of subspace correlation values in order to identify epileptogenic sources. This method was tested in three pediatric patients with intractable epilepsy, with encouraging clinical results. Each patient was evaluated using structural MRI, long-term video EEG monitoring with scalp electrodes, and subsequently with subdural electrodes. The ECoG data were then recorded from implanted subdural electrode grids placed directly on the surface of the cortex. MRI and computed tomography images were also obtained for each subject.
The epileptogenic zones identified from preoperative EEG data were validated by observations from postoperative ECoG data in all three patients. These preliminary results suggest that it is possible to direct surgical planning and locate epileptogenic zones noninvasively using the described imaging and integrating methods. EEG findings were further validated by the surgical outcomes of all three patients. After surgical resectioning, two patients are seizure-free and the third has experienced a significant reduction in seizures. Due to its clinical success, FINE offers a promising alternative to preoperative ECoG, providing information about both the location and extent of epileptogenic sources through a noninvasive imaging procedure.
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https://en.wikipedia.org/wiki/Electrocorticography
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