The effect of a 50 Hz magnetic field on cognitive function in humans

Abstract

Objectives: To examine whether the power frequency magnetic field of 0.6 mT applied to humans has an effect on cognitive function as has been suggested by animal studies. These fields are less than the suggested intervention level in the UK of 1.6 mT and are similar to those found close to some domestic appliances. Method and materials: A randomized three-way cross-over design using a battery of computerized cognitive function tests were used in the presence or absence of a 50Hz or static magnetic field. Sixteen healthy volunteers undertook two training and three test sessions with a 50Hz or static 0.6 mT magnetic field from a set of coils centred on the head. Results: In response to the 50Hz field, disruptions of accuracy were seen from an attentional task (the ability to correctly recognize words shown 20min previously and the ability to maintain a string of digits in working memory). There was no similar response to comparable levels of static magnetic field. Conclusions: These tests indicated at least temporary deterioration in attention, and working and secondary memory performance while a 50 Hz field is applied. There were no adverse effects on speed from any of the tasks. It was not possible in this study to be sure if these effects were persistent.