Effects of an ELF (50 Hz, 1 mT) electromagnetic field (EMF) on concentration in visual attention, perception and memory including effects of EMF sensitivity.

To investigate psychological effects of an extremely low frequency (ELF)-electromagnetic field (EMF), an experiment with three conditions was designed. EMF field of 50 Hz and 1 mT accompanied by 45 dB SPL noise (EMF + noise), noise, and control. A group of 66 subjects (Ss) participated in the control and in one of the experimental conditions. The sequence of conditions (expositions) was balanced. Expositions were double-blind (except for the obvious control), lasted 1 h and were separated by a 1 h pause. During exposition Ss (three by three) performed tests on attention, perception, memory and filled out a psychological questionnaire. Statistical analysis (one-tailed probability) showed less attention (P < 0.05), perception (P < 0.05) and memory performance (P < 0.1) in Ss exposed to EMF + noise compared with control, whereas for noise versus control no difference was found. Comparing EMF + noise versus noise related to control, reduced perception, less memory performance and more discomfort was observed (P < 0.1). Dividing Ss according to their self-rated sensitivity to EMF, all differences disappeared in the low sensitivity group (N = 30) and were pronounced in sensitive Ss (N = 36). Results indicate an immediate reduction of cognitive performance in attention, perception and memory performance by a 50 Hz EMF of 1 mT. These effects seem to be modulated by the self-perception of sensitivity to EMF.