Eltiti S, Wallace D, Zougkou K, Russo R, et al. (2007):
aims of this study were:
The authors carried out a pilot study that helped develop an EHS questionnaire. In the next study they revised the questionnaire and sent it to a randomly selected sample of 20,000 people. Completed questionnaires were received from 18.2%. Principal components analysis of the symptoms resulted in 8 subscales: neurovegetative, skin, auditory, headache, cardiorespiratory, cold related, locomotor, and allergy related symptoms. The next study established the validity of the questionnaire in that EHS individuals showed a higher severity of symptoms on all subscales compared to the control group.
The authors state that the scale provides an index of the type and severity of symptoms commonly experienced by people believing themselves to be EHS and a screening tool that researchers can use to pre-select the most sensitive individuals to take part in their research.