To analyze whether the electric current perception threshold of different groups of persons reporting electromagnetic hypersensitivity differs significantly from the general population and to which extent recruitment influences the results, three groups of self-declared electromagnetic hypersensitive persons were investigated. Self-declared electromagnetic hypersensitivity persons were selected 1) from members of a self aid group (25 women and 12 men), 2) from responders to a newspaper call (23 women and 6 men), and 3) from persons actively asking for investigations in their search for help (15 women and 9 men).
Exposure duration: until first perception of current
The data showed that quantitative electrosensitivity was quite different among the three groups. The members of the self aid group exhibit a considerable overlap with general population. Pooled together as a group it could be shown that hypersensitive persons differ significantly from the general population, however with a pronounced overlap with the normal range.
It can be concluded that electromagnetic hypersensitivity groups are very inhomogeneous and contain numerous persons with no increased ability to perceive low frequency electric or magnetic fields. This investigation shows the importance of the study design, in particular of the recruitment strategies of electromagnetic hypersensitivity persons.