In the scientific literature and in the media several terms are used to describe two phenomenona:
Both phenomena are considered independent from each other. Electrosensibility alone does not necessarily lead to the development of electrosensitivity. The assumption of independence is supported by the fact that healthy individuals can show an increased electrosensibility without developing any health symptoms. Likewise, it is possible that some electrosensitive individuals can detect electromagnetic fields more precisely than the average population.
As of 2005, the World Health Organization (WHO) continued to use the term electromagnetic hypersensitivity (EHS) "since the term is in common usage" (WHO 2005, fact sheet 296; WHO 2010, fact sheet 193). In 2004, the WHO introduced the term idiopathic environmental intolerance (IEI) - electromagnetic field attributed symptoms (WHO 2004, Workshop on EHS in Prague). IEI-EMF was proposed to replace terms that implied an established causal relationship between symptoms and electromagnetic fields. Idiopathic environmental intolerance (IEI) is a general term for sensitivity to environmental factors and incorporates a number of disorders sharing similar non-specific medically unexplained symptoms (WHO 2005, fact sheet 296). One of these disorders is multiple chemical sensitivity (MCS), that can occur in some cases together with electrosensitivity and exhibit similar symptoms.
The reported symptoms are generally non-specific and no consistent set of symptoms has been identified yet (WHO 2004, Workshop on EHS in Prague). Some subjects experience only symptoms if they are exposed to a specific exposure source; others claim sensitivity to a range of exposure sources (Health Protection Agency, HPA, UK).
Different symptoms like headache, sleep disorder, dizziness, fatigue, concentration difficulties, tiredness, nausea or heart palpitations are often reported in association with different exposure sources (mobile phones, base stations, power transmission lines, radar, household devices). Occasionally, muscle pain or otorhinolaryngological symptoms are reported (e.g. tinnitus, hearing problems).
The first reports on subjective complaints in association with electromagnetic fields came from Russia in the 1960's. Those were part of company medical investigations that were performed on a regular basis. Exposure sources were mainly electromagnetic fields that were used for industrial purposes (e.g. radarstations, power transmission lines) and exposure duration was several years (occupational exposure; Hecht et al. 2001). The observed subjective complaints included headache, fatigue, irritability, dizziness and emotional instability.
Outside of Russia, the phenomenon of electrosensitivity was first observed in Norway. In 1979, the Local Labour Inspection of the city of Bergen received a complaint about itching and erythemia in association with work on visual display units (type: cathode ray tube). Back then, the symptoms were classified as "occupational dermatitis" (Linden & Rolfson 1981). As the information circulated through the media, it prompted reports of other cases in Bergen and other regions of Norway.
In the following years, sporadic publications on this phenomenon appeared in Great Britain (Rycroft et al. 1984) and the United States (Feldman et al. 1985). In 1985, a Swedish Health Insurance Company approved the complaints of three dermatitis patients as occupational disease because the possibility of a relationship between their symptoms and the occupation with visual display units could not be totally eliminated. This initial case led to an increase of the phenomenon in epidemic fashion in Sweden (Frick et al. 2004).
With time, the original focus on visual display units extended to several electromagnetic field sources causing symptoms. The individuals who were reporting such symptoms saw themselves as sufferers of a new disease: hypersensitivity to electricity. Over the years, several unspecific neurovegetative symptoms were reported, in addition to skin symptoms as well (see Symptoms).
In Europe, there is a large difference in the prevalence of electrosensitivity with a strong north-south and east-west gradient (higher case numbers in the former regions [Sweden, Norway, Denmark, Germany, Austria]). The highest case number are reported in occupational health centers from Germany and Sweden. Estimated numbers from surveys from the United States and Sweden show that 1.5% up to 3.2% of the general population may be suffering from electrosensitivity (Frick et al. 2004). It should be noted that the prevalence of symptoms in Western Europe varies strongly between countries, although comparable electromagnetic field environment can be found in all countries. This indicates that other factors, such as public risk perception or media coverage may have an influence.
Countries differ in the reported exposure sources and also in the associated symptoms. In the Scandinavian countries, most subjects report skin symptoms and associate these effects with exposure sources from their work environment (occupational exposure). In contrast, in Germany the exposure sources occur more often in the residential environment and neurasthenic symptoms (e.g. headache, sleep disorder, dizziness, fatigue, concentration difficulty, tiredness, nausea or heart palpitation) are reported frequently. In Europe and Great Britain, mainly radio frequency sources are associated with health risks (e.g. base stations, television transmitters, radar stations, mobile phones), while in Scandinavian countries exposure sources in the low frequency range (monitors, fluorescent lights) are associated with health risks (Frick et al. 2004).
In a study of patients suffering from electrosensitivity with somatic symptoms (Andersson et al. 1996), it has been observed that a treatment with cognitive-behavioral therapy led to reduced evaluations of disability in the treatment group compared to the control group. This indicates that psychological mechanisms might be involved in the disease.
Rubin et al. (2010) discovered in several provocation studies with hypersensitive participants that sham exposures were sufficient to trigger symptoms. The authors hypothesized that nocebo effects may account for the finding. The mechanism would predict that conscious expectation of symptoms following perceived electromagnetic exposure would result in the formation of symptoms.
In contrast, Johansson (2006) concluded that electrosensitivity is a functional impairment which is in some cases mediated by a heigthened density of mast cells in the skin. Another hypothesis assumes a psychosomatisation mechanism for different forms of environmental intolerance (e.g. multiple chemical sensitivity, electrosensitivity) that all involve the same pathophysiologic disregulation mechanism, and decompensated neuroendocrine response to stress (Barsky & Borus 1999). Studies that compared healthy and electrosensitive individuals in their baseline physiological activity found differences in heart rate and electrodermal activity between groups (Lyskov et al. 2001). An underlying imbalance in the regulation of the autonomic nervous system (WHO 2004, Workshop on EHS in Prague) could lead to an increased vulnerability to a variety of psychological and physical stressors.
In a conditioning hypothesis symptoms get associated with the experience of stress. Berg et al. (1992) examined office workers who experienced occupational stress at their workplace and suffered from skin symptoms. Elevated levels of stress hormones, elevated metabolism and increased blood flow in the skin were measured. The workplace (computer terminal) itself originally did not trigger any reaction, just experienced work strain led to the observed physiological changes. However, if these physiological reactions occurred several times in a close temporal sequence with working at the computer terminal, the presence of the computer terminal alone was sufficient to trigger the physiological reactions. Symptoms now could occur even in the absence of occupational strain.
The psychological three-phase-model is based on observations from a medical skin department in Kristianstad (Sweden) and was formulated by Harlacher & Schahn (1998).
In phase 1 the primary symptoms occur. After several consultations without a clear diagnosis, the person starts self-researching a diagnosis for his/her complaints.
In phase 2 the suspicion of being electrosensitive gets supported. The person tests this assumption through self-exposure and by focusing the attention strongly on the perception of own body signals. External stimuli get masked which leads to a more intense experience of own body signals. Furthermore, physiological reactions (e.g. skin symptoms) can be influenced through cognitive stress. After repeated self-exposure to electromagnetic sources during periods of elevated occupational stress, the physiological stress reactions turn into a conditional response. Exposure to the electromagnetic source now gets associated with the typical physiological reactions to stress.
In phase 3 the person creates a cognitive scheme of electrosensitivity, i.e. a biased information filter system that continuously proves itself: If the person experiences symptoms, an electromagnetic exposure source is searched and found. If no symptoms occur the search for exposure sources stops. Only expected information is recepted and incomplete information is amended according to the expectations. False recall occurs. In the context of conditioning processes, symptoms occur immediately after exposure. Depending on how automated these processes are, the cognitve scheme can be in the best case corrected easily or in the worst case not at all.
 Barsky A, Borus J (1999). Functional somatic syndromes. Ann. Intern. Med. 130 (11), 910-921.
The World Health Organization (WHO) issues the international classification of diseases ICD-10, that is recognized and used for diagnostical purposes by medical health professionals worldwide. According to the WHO, electrosensitivity has no clear diagnostic criteria and is not a medical diagnosis. It is also not clear whether it represents a single medical problem (WHO 2005, Factsheet 296). There exists no known biological marker for electrosensitivity (WHO 2004, Workshop on EHS in Prague). The WHO recommends that in absence of any identified disease, diagnosis should be based on the most pronounced symptoms (e.g. headache) according to ICD-10 or DSM-IV (Diagnostic and Statistical Manual 4th edition, for psychiatric disorders). In the ICD-10 electrosensitivity could also be coded under chapter XXI Z58ff (problems related to the physical environment). This category documents reasons why a person contacted a medical doctor (e.g. Z58.4 exposure to radiation).
In Germany, the german version of the ICD-10 is used for coding of diagnoses in ambulant and in-patient treatment (§§ 295 and 301 SGB V) since 2000. Lobbyists of the electrosensitive (e.g. Workshop Anerkennungsverfahren) support efforts for acceptance of electrosensitivity as an organic disease in the ICD-10. According to its current recognition status in Germany, electrosensitivity is treated under other diagnoses (e.g. multiple chemical sensitivity, skin diseases, somatic diseases) or patients pay the treatment themselves.
In Sweden, electrosensitivity is an officially recognized functional impairment (i.e. it is not regarded as a disease). According to the Swedish National Board of Health and Welfare (SNBHW) electrosensitivity is a psychological phenomenon with no basis in physical or physiological mechanisms (Hallberg et al. 2006). Johansson (2006) states that in Sweden impairments are viewed from a general environmental perspective. No human being is in itself impaired, there are instead shortcomings in the environment that cause the impairment. This environment-related view, furthermore, means that even though one does not have a scientifically based complete explanation for the impairment electrosensitivity, and in contrast to disagreements in the scientific society, the person with electrosensitivity shall always be met with all necessary support with the goal to eliminate the impairment (e.g. having the opportunity to live and work in an electrosanitized environment) .
To investigate the influence of electromagnetic fields on the development of symptoms (e.g. electrosensitivity), experimental provocation studies are a valuable tool. In these studies, volunteers (e.g. healthy participants, electrosensitive persons or both groups) are exposed once or several times to electromagnetic fields (=provocation) under controlled experimental conditions in the laboratory. The results can be compared within and between groups by means of statistical evaluation procedures. However, during the experimental procedures several problems can arise with regards to electrosensitvity:
From 27 available studies on the effects of mobile phone related radiofrequency electromagnetic fields on electrosensitivity (see table as of september 2010), 24 studies were experimental provocation studies. From the remaining three studies, electromagnetic fields were systematically shielded in one study (Augner et al. 2009). In one observational study electromagnetic fields were measured in the residential area (Hutter et al. 2006). In a second observational study blood parameters of patients with electrosensitivity were measured without further specification of exposure parameters (Dahmen et al. 2009). Additionally, in 17 of the 24 provocation studies the perception of electromagnetic fields (=electrosensibility) was examined.
The investigated samples differed between studies: In 13 studies, individuals reporting subjective symptoms or electrosensitivity were compared to healthy control subjects. Five studies focused only on electrosensitive individuals (no control group). Four studies only examined healthy participants. In another four studies, the health status of the recruited participants was not specified (Cinel et al. 2008; Heinrich et al. 2007; Hutter et al. 2006; Blackmore et al. 2002). In one study, electrosensitive persons were neither actively recruited nor excluded Augner et al. 2009).
Regarding the exposure sources, in the majority of the studies (n=18) a mobile phone or an antenna were used (mostly partial body exposure on head or ear). Eight studies examined the effects of electromagnetic exposure from a base-station (whole body exposure). A single study (Blackmore et al. 2002) tested the effectiveness of a bioelectric shield to protect mobile phone exposure. In seven of the 27 studies, the experimental exposure room was shielded to prevent external interfering electromagentic exposure from the environment.
Besides electrosensitivity, some studies also investigated other endpoints: sleep (e.g. Hutter et al. 2006), EEG (e.g. Kleinlogel et al. 2008), cognitive performance (e.g. Eltiti et al. 2009; Regel et al. 2006), effects on immune system (e.g. Dahmen et al. 2009; Hillert et al. 2008) or blood pressure (e.g. Stovner et al. 2008; Hietanen et al. 2002; Braune et al. 1998).
From all studies, 21 measured subjective symptoms, well-being or mood parameters via questionnaires or visual analog scales. Two studies specifically investigated headache as a symptom (Stovner et al. 2008; Oftedal et al. 2007). Two other studies investigated the perception of electromagnetic fiels (=electrosensibility) without further examining subjective symptoms (Kaul 2009; Radon & Maschke 1998). One study tested the influence of individual accurancy feedback on subjective symptoms and the perceived ability to discriminate an active mobile phone signal from a sham exposure (Nieto-Hernandez et al. 2008). One study compared several blood parameters of electrosensitive persons and healthy controls (Dahmen et al. 2009).
Additionally, ten studies assessed physiological parameters (e.g. heart rate, electrodermal activity, respiration) besides subjective effects, to examine functioning of the autonomic nervous system. With these parameters differences in stress reaction of electrosensitive individuals and healthy persons can be visualized.
In 20 of all studies, no effects of mobile phone related electromagnetic fields on the investigated endpoints were observed. Also the ability to perceive electromagnetic fields could not be proven. The results of the remaining seven studies were very heterogenous: One study reported a statistically significant increase in dizziness in one exposure group (Cinel et al. 2008). In one study a sympathetic dominance in the autonomic nervous system of electrosensitive individuals compared to healthy subjects was observed (Wilen et al. 2006), while another study found a significantly higher level of skin conductance in electrosensitive particpants compared to controls (Eltiti et al. 2009). In the TNO-study of the Netherlands Organization for Applied Scientific Research (TNO) (Zwamborn et al. 2003) significant negative effects of UMTS exposure on well-being and cognitive functioning were observed. These effects were not supported in a later study (Regel et al. 2006). Dahmen et al. (2009) compared blood parameters of electrosensitive patients and healthy individuals and identified signs of thyroid dysfunction, liver dysfunction and chronic inflammatory processes in a small but remarkable fraction of patients as potential sources of symptoms.
Some surprising results were reported as well: Augner et al. (2009) observed that participants that received high or medium exposure were significantly calmer during the sessions than participants in the low exposure condition. The data of Hillert et al. (2008) showed that headache was more commonly reported after exposure than sham exposure, however mainly due to an increase in the control group instead of the electrosensitive group.
The following authors provided reviews on the potential effects of electromagnetic fields in the frequency band of mobile phones, especially with regard to influences on electrosensitivity, well-being and subjective complaints:
In 2005, the World Health Organization (WHO) issued a Factsheet (Nr.296) on electrosensitivity. In a recent Factsheet (Nr. 193) from 2010 on the topic 'Electromagnetic fields and public health: mobile phones' the WHO states: "To date, research does not suggest any consistent evidence of adverse health effects from exposure to radiofrequency fields at levels below those that cause tissue heating. Further, research has not been able to provide support for a causal relationship between exposure to electromagnetic fields and self-reported symptoms, or 'electromagnetic hypersensitivity'."
In Germany, the German Commission on Radiological Protection (SSK) advises the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU). In 2008, the SSK issued a report on the studies of the German Mobile Telecommunication Research Programme, which also include the topic electrosensitivity. The SSK concluded that the studies did not support the assumption of a causal relationship between electromagnetic fields and health complaints. Even though the evaluated studies had different inclusion criteria for recruitment of participants the final review of the literature showed that the phenomenon electrosensitivity is most likely not existing. The closing report of the German Mobile Telecommunication Research Programme (Health Risk Assessment of Mobile Communications) states more detailed: "Taken together, a causal relationship between electromagnetic fields and symptoms of individuals suffering from electrosensitivity can be excluded with a high probability. Further, no evidence for an increased vulnerability to allergies and/or chemical agents and/or a reduced detoxication capacity of the liver was found. With regards to other medical parameters some deviations of electrosensitive persons compared to the general population/control samples were observed. Electrosensitive persons seem to represent a heterogenous group that cannot be specified in a simple model. According to the results of the German Mobile Telecommunication Research Programme a deficient processing of environmental influences and/or a limited ability of the nervous system to adapt to environmental stimulation is a potential explanation for the development and/or retention of electrosensitivity."
The Swiss Federal Office for the Environment (FOEN) published a comprehensive evaluation on radiofrequency exposure and health (FOEN 2006) and drew the following conclusions on the subtopic 'Electrosensibility': "With regards to the [...] results it cannot be ruled out that single individuals [...] are able to perceive radio frequency electromagnetic fields. However, these cases are exceptional and do not represent the majority of self-reported electrosensitive individuals. [...] This scientific field needs further research."
On the subtopic 'Unspecific symptoms, electrosensitivity' FOEN stated: "Existing research studies do not support the assumption that short-term exposure to radiofrequency electromagnetic fields [...] leads to different health effects than sham exposure, also not in the sub-population of electrosensitive individuals. [...] No statements can be given for long-term exposures." With regards to epidemiological studies "is seems likely that increased occurrence of unspecific symptoms is associated with increased mobile phone use. Whether this increase of symptoms is caused by radiofrequency electromagnetic exposure or co-factors of mobile phone use cannot be said."