Original ArticleNeurophysiological Effects of Flickering Light in Patients with Perceived Electrical HypersensitivitySandström, Monica BSc; Lyskov, Eugene MD, PhD; Berglund, André; Medvedev, Sviatoslav MD, PhD; Hansson Mild, Kjell PhDAuthor Information From the Department of Environmental Medicine. University of Umeå, Umeå, Sweden (Mrs Sandström); the National Institute for Working Life, Umeå, Sweden (Mrs Sandström, Mr Berglund, Dr Hansson Mild); and the Institute of the Human Brain, St Petersburg, Russia (Dr Lyskov, Dr Medvedev). This article was presented at the Cost 244: Electromagnetic Hypersensitivity, Graz, Austria, September, 1994; and the 7th International Congress of Psychophysiology, Thessaloniki, Greece, September 1994. Address correspondence to: Kjell Hansson Mild, PhD, National Institute for Working Life, Box 7654, S-907 13 Umeå, Sweden. Journal of Occupational & Environmental Medicine: January 1997 - Volume 39 - Issue 1 - p 15-22 Buy Abstract An increasing number of people in Sweden are claiming that they are hypersensitive to electricity. These patients suffer from skin as well as neurological symptoms when they are near computer monitors, fluorescent tubes, or other electrical appliances. Provocation studies with electromagnetic fields emitted from these appliances have, with only one exception, all been negative, indicating that there are other factors in the office environment that can effect the autonomic and/or central nervous system, resulting in the symptoms reported. Flickering light is one such factor and was therefore chosen as the exposure parameter in this study. Ten patients complaining of electrical hypersensitivity and the same number of healthy voluntary control subjects were exposed to amplitude-modulated light. The sensitivity of the brain to this type of visual stimulation was tested by means of objective electrophysiological methods such as electroretinography and visual evoked potential. A higher amplitude of brain cortical responses at all frequencies of stimulation was found when comparing patients with the control subjects, whereas no differences in retinal responses were revealed. © Williams & Wilkins 1997. All Rights Reserved.