Resting EEG effects during exposure to a pulsed ELF magnetic field.
Continuing evidence suggests that extremely low frequency magnetic fields (ELF MFs) can affect animal and human behavior. We have previously demonstrated that after a 15 min exposure to a pulsed ELF MF, with most power at frequencies between 0 and 500 Hz, human brain electrical activity is affected as measured by electroencephalography (EEG), specifically within the alpha frequency (8-13 Hz). Here, we report that a pulsed ELF MF affects the human EEG during the exposure period. Twenty subjects (10 males; 10 females) received both a magnetic field and a sham session of 15 min in a counterbalanced design. Analysis of variance (ANOVA) revealed that alpha activity was significantly lower over the occipital electrodes (O1, Oz, O2) [F(1,16) = 5.376, P < .01, eta2 = 0.418] after the first 5 min of magnetic field exposure and was found to be related to the order of exposure (MF-sham vs. sham-MF). This decrease in alpha activity was no longer significant in the 1st min post-exposure, compared to sham (P > .05). This study is among the first to assess EEG frequency changes during a weak (+/-200 microTpk), pulsed ELF MF exposure.
Cook
Charles M
CM
Department of Nuclear Medicine, Lawson Health Research Institute, St. Joseph's Health Care (London), London, Ontario, Canada. ccook@lri.sjhc.london.on.ca
Thomas
Alex W
AW
Keenliside
Lynn
L
Prato
Frank S
FS
D000222:Adaptation, Physiological / Q000502:physiology / Q000528:radiation effects; D000328:Adult; D001921:Brain / Q000502:physiology* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004569:Electroencephalography / Q000379:methods / Q000528:radiation effects*; D004574:Electromagnetic Fields; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D011829:Radiation Dosage; D012146:Rest / Q000502:physiology*