Human cognitive performance in a 3 mT power-line frequency magnetic field

Bioelectromagnetics. 2011 Dec;32(8):620-33. doi: 10.1002/bem.20676. Epub 2011 May 4.


Extremely low frequency (ELF, <300 Hz) magnetic fields (MF) have been reported to modulate cognitive performance in humans. However, little research exists with MF exposures comparable to the highest levels experienced in occupations like power line workers and industrial welders. This research aims to evaluate the impact of a 60 Hz, 3 mT MF on human cognitive performance. Ninety-nine participants completed the double-blind protocol, performing a selection of psychometric tests under two consecutive MF exposure conditions dictated by assignment to one of three groups (sham/sham, MF exposure/sham, or sham/MF exposure). Data were analyzed using a 3 × 2 mixed model analysis of variance. Performance between repetitions improved in 11 of 15 psychometric parameters (practice effect). A significant interaction effect on the digit span forward test (F = 5.21, P < 0.05) revealed an absence of practice effects for both exposure groups but not the control group. This memory test indicates MF-induced abolition of the improvement associated with practice. Overall, this study does not establish any clear MF effect on human cognition. It is speculated that an ELF MF may interfere with the neuropsychological processes responsible for this short-term learning effect supported by brain synaptic plasticity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analysis of Variance
  • Brain / physiology
  • Brain / radiation effects
  • Cognition / physiology
  • Cognition / radiation effects*
  • Double-Blind Method
  • Electromagnetic Fields / adverse effects*
  • Female
  • Humans
  • Magnetic Fields / adverse effects*
  • Male
  • Middle Aged
  • Occupational Exposure / adverse effects*
  • Psychological Tests*
  • Reaction Time / physiology
  • Reaction Time / radiation effects
  • Task Performance and Analysis*