Topic

Investigation of the phenomenon of 'electromagnetic hypersensitivity' using an epidemiological study on 'electrosensitive' patients including the determination of clinical parameters

Start

01.08.2004

End

31.07.2006

Project Management

District hospital of Regensburg

Objective

The objective of this project was to examine the phenomenon of 'electromagnetic hypersensitivity' of patients believing to be hypersensitive to the electromagnetic fields of mobile telecommunication systems. The study should clarify whether the self-diagnosis of electromagnetic hypersensitivity is based on a particular sensitivity to or perception of electromagnetic fields and how the 'electrosensitive' group is characterised with respect to psychological and laboratory-clinical parameters.

To this end, a group of persons believing themselves to be 'electrosensitive' to electromagnetic fields of mobile telecommunications was compared to a control group. The study should address the following points, among others:

• Health complaints / symptoms, quality of life and self-contentment and accompanying factors;
• Clinical tests to objectively determine the volunteers' state of health;
• Physical medical tests under various exposure conditions.

Results

89 subjectively electrosensitive persons and 107 controls could be gained for the investigation. The electrosensitive persons included in the study must not be seriously ill, they had to have a high symptom load and they had to attribute their symptoms to concrete sources of electromagnetic fields. The controls were matched to the electrosensitive persons by age, sex, EMF exposure at home or EMF exposure at the working place. The research program included some questionnaires on type and intensity of the symptoms, concomitant diseases and sleep quality. Furthermore, the so-called “allostatic load” (clinical-medical parameters which are stress relevant and permit statements on the further health development of a person) and the existence of certain genetic factors were examined. With the help of the transcranial magnetic stimulation (TMS) the subjective and objective perception threshold and the competence to perceive magnetic pulses and the so-called “excitability” were assessed.

In a blinded perception experiment series of magnetic pulses of increasing intensity were applied to the volunteers´ heads. After each pulse received the volunteers should indicate if they had perceived it or not. Subsequently the objective resting threshold and the active motor threshold were measured.

With respect to the objective motor thresholds in TMS the electrosensitive persons did not differ on average from the control persons, whereas a large spectrum of perception thresholds occurred in both groups. Should electrosensitive persons actually be more sensitive to electromagnetic fields one would have to expect that they show a lower objective perception threshold, which was not the case in this study. Several other investigations showed similar results.

With respect to the competence to differentiate actual magnetic pulses from sham pulses, however, there were clear differences between electrosensitive persons and control persons. Electrosensitive persons displayed a poorer competence to differentiate true pulses from sham pulses compared to controls due to an increased false alarm rate. The corresponding results from an earlier feasibility study with a smaller number of volunteers could, thus, be basically confirmed. On the basis of the broader age distribution of the volunteers in this study it could be determined that the competence to discriminate depends on age, i. e. with increasing age it was harder for the controls to differentiate between true and sham pulses. This age-dependent impairment could not be found in the electrosensitive persons.

A double pulse examination was carried out to determine the cortical excitability. Short temporal intervals (2ms) between the two magnetic pulses resulted in an inhibition of the subsequent motor potential, long intervals (15ms), however, resulted in a facilitation. Compared with the control persons, the electrosensitive persons displayed a modified facilitation. Part of the corresponding results of the preceding feasibility study could, thus, be confirmed. However, due to the fact that older persons had been included in this study, it showed for the first time that this effect is age dependent.

With the help of different parameters of the allostatic load conclusions can be drawn on a possible impairment of health in chronically stressed persons. Measurement of these parameters did not show any differences between electrosensitive persons and control persons.

In view of possible genetic differences between electrosensitive persons and controls genes for neuronal receptors (serotonin transporter promotor gene, dopamine-D4 receptor gene) were investigated but no differences between electrosensitive persons and control persons could be found regarding the genetic equipment with respect to these two features.

When evaluating the data collected with the help of questionnaires with respect to the occurrence of dysfunctional cognitions (incorrect evaluations, attitudes) clear differences could be found between the electrosensitive persons and the controls. On the basis of answers to 6 specific questions of the questionnaires and the time required for handling the questionnaire of complaints, there was a high hit rate in allocating the volunteers to the electrosensitive persons or the control persons.

By means of functional Magnetic Resonance Imaging (fMRI), the cortical activity in case of exposure or, respectively, pronounced exposure to a thermal stimulus or a „mobile signal” was examined in 15 electrosensitive persons and 15 control persons. Under exposure to thermal stimuli the electrosensitive persons showed the same activation pattern as the control persons. Under exposure to a pretended „mobile phone signal“ no activation of special regions of the brain was observed in the control persons. However, in the electrosensitive persons, regions of the brain were activated that participate in anticipatory activities. Furthermore, part of the electrosensitive persons reported complaints during the pretended exposure to mobile phone radiation or, respectively, believed that they had perceived the radiation.

The final report of the project can be downloaded as PDF file in German (1.432 KB).

References

• Frick et al, Comparison perception of singular transcranial magnetic stimuli by subjectively electrosensitive subjects and general population controls, Bioelectromagnetics . (2005) 26:287-298
• Frick, U., Mayer, M., Hauser, S., Binder, H., Rosner, R., & Eichhammer, P., Entwicklung eines deutschsprachigen Messinstrumentes für "Elektrosmog-Beschwerden", Umweltmedizin in Forschung und Praxis (2006) 11, 103-113
• Landgrebe, M., et al., Altered cortical excitability in subjectively electrosensitive patients: Results of a pilot study. J Psychosom Res (2007) 62: 283-288
• Landgrebe M., et. al., Transkranielle Magnetstimulation zur biologischen Charakterisierung somatoformer Störungen am Beispiel der subjektiven Elektrosensibilität. Nervenheilkunde (2006) 25, 653-656

Conclusions

The objective of the project was, on the one hand, to clarify a possible cause-effect interrelation between EMF and the complaints/symptoms of the subjectively electrosensitive persons and, on the other hand, to search factors that could contribute to generating or maintaining electromagnetic hypersensitivity.

Like the preceding feasibility study, this project also showed that the electrosensitive volunteers were not able to better differentiate between true and sham pulses, however, they showed a poorer performance than control persons, since they often indicated that they had “perceived” something even in cases of sham pulses. Likewise some electrosensitive persons showed disorders as a reaction to the pretended „mobile phone signal“ they had been exposed to during the fMRI and at least indicated that they could „perceive“ the field.

In this project, as in many other investigations, no interrelation between EMF and the complaints of affected persons could be proven. A causal interrelation between EMF and the complaints can, thus, be excluded with high probability. This judgement is also shared by the World Health Organization (WHO). In the Fact Sheet No. 296 from December 2005 WHO has stated that there is no scientific basis for linking the symptoms of electrosensitive persons with exposure to electromagnetic fields.

However, since electromagnetic hypersensitivity is a serious health problem for the affected people and since such people are under high psychological strain, it is reasonable and necessary to search for other causal factors. First indications of involved factors were found within the scope of this project.

Other factors that are essential for „electromagnetic hypersensitivity“ are examined in another DMF research project. In the final report to the DMF all results will be summarised and discussed.

It is by all means reasonable to continue research associated with the phenomenon of „electromagnetic hypersensitivity“. However, it should concentrate on the predisposing factors and on possible therapies. In connection with this it is important to improve the definition of the disease pattern, this definition should then lead to a more objective selection of volunteers and, thus, hopefully to a more homogeneous group of volunteers. However, these questions cannot be solved through radiation protection research only.