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Effects of 45‐Hz magnetic fields on the functional state of the human brain
Author(s) -
Lyskov Evgeny B.,
Juutilainen Jukka,
Jousmäki Veikko,
Partanen Juhani,
Medvedev Sviatoslav,
Hänninen Osmo
Publication year - 1993
Publication title -
bioelectromagnetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.435
H-Index - 81
eISSN - 1521-186X
pISSN - 0197-8462
DOI - 10.1002/bem.2250140202
Subject(s) - electroencephalography , audiology , alpha (finance) , medicine , brain activity and meditation , anesthesia , physics , psychology , nuclear magnetic resonance , neuroscience , surgery , construct validity , patient satisfaction
The influence of sinusoidal 45‐Hz magnetic fields on the brain functions of 20 volunteers was investigated in a double‐blind study using spectral analysis of EEG and measurements of Omega potentials and reaction time (RT). The field strength was 1,000 A/m (1.26 mT) and the duration of exposure was 1 h. Ten volunteers were exposed to a continuous field and ten received an intermittent exposure (1 s on/1 s off). Each person received one real and one sham exposure. One half of the volunteers got the real exposure first and the sham treatment after at least 24 h. For the rest, the sequence was inverse. The measurements of EEG, omega potentials and RT were performed before and after each exposure. Several statistically significant changes were observed, most of them after intermittent exposure. In the EEG, an increase of alpha (7.6–13.9 Hz) activity and a decrease of delta (1.5–3.9 Hz) activity were observed. β waves (14.2–20 Hz) increased in the frontal derivations as did the total power in occipital derivations. The mean and peak frequencies of EEG increased mainly in the frontal derivations. No direct effects on RT were seen. Learning to perform the RT test (decrease of RT in repeated trials), however, seemed to be affected by the exposure. The persons who received real exposure first learned more slowly than those who got sham exposure first. Further experiments are necessary to confirm the findings and for understanding the mechanisms of the effects. © 1993 Wiley‐Liss. Inc.