Electromagnetic hypersensitivity (EHS) is a proposed pathological sensitivity to electromagnetic fields in the environment. EHS is not a recognised medical diagnosis, and there is no scientific basis for it.
Those who are self-described with EHS report responding to low-level electromagnetic fields at intensities well below the maximum levels permitted by international radiation safety standards. Claims are characterized by a "variety of non-specific symptoms, which afflicted individuals attribute to exposure to electromagnetic fields". The supposed effects of EHS are often vague and inconsistent. Terms used in this context include idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF), electrohypersensitivity, electro-sensitivity, and electrical sensitivity (ES). Idiopathic refers to the fact that the cause is unknown.
The majority of provocation trials to date have found that self-described sufferers of electromagnetic hypersensitivity are unable to distinguish between exposure and non-exposure to electromagnetic fields. A systematic review in 2005 showed no convincing scientific evidence for symptoms being caused by electromagnetic fields. Since then several double-blind experiments have shown that people who report electromagnetic hypersensitivity are unable to detect the presence of electromagnetic fields and are as likely to report ill health following a sham exposure as they are following exposure to genuine electromagnetic fields, suggesting the cause in these cases to be the nocebo effect.
Signs and symptoms Edit
Although the thermal effects of electromagnetic fields on the body are established and even exploited (e.g. in diathermy), symptoms ascribed to EHS are claimed to be caused by levels of exposure well within international safety standards.
There are no specific symptoms associated with claims of EHS and reported symptoms range widely between individuals. They include headache, fatigue, stress, sleep disturbances, skin prickling, burning sensations and rashes, pain and ache in muscles and many other health problems. In severe cases such symptoms can be a real and sometimes disabling problem for the affected person, causing psychological distress. There is no scientific basis to link such symptoms to electromagnetic field exposure.
The prevalence of some reported symptoms is geographically or culturally dependent and does not imply "a causal relationship between symptoms and attributed exposure". Many such reported symptoms overlap with other syndromes known as symptom-based conditions, functional somatic syndromes, and IEI (idiopathic environmental intolerance).
Those reporting electromagnetic hypersensitivity will usually describe different levels of susceptibility to electric fields, magnetic fields, and various frequencies of electromagnetic waves. Devices implicated include fluorescent and low-energy lights, mobile, cordless/portable phones, and WiFi. A 2001 survey found that people self-diagnosing as EHS related their symptoms most frequently to mobile phone base stations (74%), followed by mobile phones (36%), cordless phones (29%), and power lines (27%). Surveys of electromagnetic hypersensitivity sufferers have not been able to find any consistent pattern to these symptoms.
Most blinded conscious provocation studies have failed to show a correlation between exposure and symptoms, leading to the suggestion that psychological mechanisms play a role in causing or exacerbating EHS symptoms. In 2010 Rubin et al. published a follow-up to their 2005 review, bringing the totals to 46 double-blind experiments and 1175 individuals with self-diagnosed hypersensitivity. Both reviews found no robust evidence to support the hypothesis that electromagnetic exposure causes EHS, as have other studies. They also concluded that the studies supported the role of the nocebo effect in triggering acute symptoms in those with EHS. The Essex provocation study of 2007 received some criticism for its methodology and analysis. In their response the authors noted that their study says nothing about long-term effects, but that those affected often claim to respond to the fields within a few minutes.
Some psychologists have suggested that severely affected EHS people who claim that they are unable to live in a wireless society are, like hermits of ancient times, escaping from the pressures of modern life. In addition, scare stories in the media seem capable of increasing the likelihood of the symptoms ascribed to electromagnetic exposure.
Some other types of studies suggest evidence for symptoms at non-thermal levels of electromagnetic exposure. A review in 2010 of ten studies on neurobehavioral and cancer outcomes near cell phone base stations found eight with increased prevalence, including sleep disturbance and headaches. Since 1962 the microwave auditory effect or tinnitus has been shown from radio frequency exposure at levels below significant heating. Studies during the 1960s, among workers in the USSR and Poland with occupational electromagnetic exposure, claimed to show a set of symptoms called the ‘microwave syndrome’. Other areas under study include sensitivity shown through subliminal or autonomic effects as well as conscious effects. These include increased rates of stroke during geomagnetic events, aurora sensitivity. These effects do not necessarily relate to conscious sensitivity.
Other studies on sensitivity have looked at therapeutic procedures using non-thermal electromagnetic exposure, genetic factors, an alteration in mast cells, oxidative stress, protein expression and voltage-gated calcium channels. Mercury release from dental amalgam and heavy metal toxicity have also been implicated in exposure effects and symptoms. Another line of study has been the nature of hyper-sensitivity or intolerance and the range of environmental exposures which may be related to it. Some 80% of people with self-diagnosed electromagnetic intolerance also claim intolerance to low levels of chemical exposure.
Electromagnetic hypersensitivity is not an accepted diagnosis. Medically there is no case definition or clinical practice guideline and there is no specific test to identify it. There are no accepted research criteria beyond 'self-reported symptoms.'
Complaints of electromagnetic hypersensitivity may mask organic or psychiatric illness. Diagnosis of those underlying conditions involves investigating and identifying possible known medical causes of any symptoms observed. It may require both a thorough medical evaluation to identify and treat any specific conditions that may be responsible for the symptoms, and a psychological evaluation to identify alternative psychiatric/psychological conditions that may be responsible or contribute to the symptoms.
For individuals reporting electromagnetic hypersensitivity with long lasting symptoms and severe handicaps, treatment therapy should be directed principally at reducing symptoms and functional handicaps. This should be done in close co-operation with a qualified medical specialist to address the symptoms and a hygienist (to identify and, if necessary, control factors in the environment that have adverse health effects of relevance to the patient).
Those who feel they are sensitive to electromagnetic fields generally try to reduce their exposure to electromagnetic sources as much as is practical. Complete avoidance of electromagnetic fields presents major practical difficulties in modern society. Methods often employed by sufferers include: avoiding sources of exposure; disconnecting or removing electrical devices; shielding or screening of self or residence; medication; and complementary and alternative therapy.
The UK Health Protection Agency reviewed treatments for electromagnetic hypersensitivity, and success was reported with "neutralizing chemical dilution, antioxidant treatment, Cognitive Behavioural Therapy, Acupuncture and Shiatsu". It was noted that:
The studies reviewed suffer from a combination of the small numbers of subjects included and the potential variation both within and between study populations. Little information is given as to the attributed exposures of the subjects. These factors limit their general applicability outside the immediate study group. For those studies where detail was available, only two were placebo controlled [Acupunture and nutrition intervention].
It was also noted in the review that success may have more to do with offering a caring environment as opposed to a specific treatment.
A 2006 systematic review identified nine clinical trials testing different treatments for ES: four studies tested cognitive behavioural therapy, two tested visual display unit filters, one tested a device emitting 'shielding' electromagnetic fields, one tested acupuncture, and one tested daily intake of tablets containing vitamin C, vitamin E, and selenium. The authors of the review concluded that:
The evidence base concerning treatment options for electromagnetic hypersensitivity is limited and more research is needed before any definitive clinical recommendations can be made. However, the best evidence currently available suggests that cognitive behavioural therapy is effective for patients who report being hypersensitive to weak electromagnetic fields.
Some Americans with the condition have moved to the United States National Radio Quiet Zone where wireless signals are restricted. Others have sought refuge by living off the grid.
The prevalence of claimed electromagnetic hypersensitivity has been estimated as being between a few cases per million to 5% of the population depending on the location and definition of the condition.
In 2002, a questionnaire survey of 2,072 people in California found that the prevalence of self-reported electromagnetic hypersensitivity within the sample group was 3% (95% CI 2.8–3.68%), with electromagnetic hypersensitivity being defined as "being allergic or very sensitive to getting near electrical appliances, computers, or power lines" (response rate 58.3%).
A similar questionnaire survey from the same year in Stockholm County (Sweden), found a 1.5% prevalence of self-reported electromagnetic hypersensitivity within the sample group, with electromagnetic hypersensitivity being defined as "hypersensitivity or allergy to electric or magnetic fields" (response rate 73%).
A 2004 survey in Switzerland found a 5% prevalence of claimed electromagnetic hypersensitivity in the sample group of 2,048.
In 2007, a UK survey aimed at a randomly selected group of 20,000 people found a prevalence of 4% for symptoms self-attributed to electromagnetic exposure.
A group of scientists also attempted to estimate the number of people reporting "subjective symptoms" from electromagnetic fields for the European Commission. In the words of a HPA review, they concluded that "the differences in prevalence were at least partly due to the differences in available information and media attention around electromagnetic hypersensitivity that exist in different countries. Similar views have been expressed by other commentators."
Sources : Straight outta wikipedia