Document Detail

Absence of daytime 50 Hz, 100 microT(rms) magnetic field or bright light exposure effect on human performance and psychophysiological parameters.
MedLine Citation:
PMID:  15768425     Owner:  NLM     Status:  MEDLINE    
The purpose of this study was to reproduce and extend two earlier studies of the effects of human exposure to 50 Hz magnetic fields (MF). In a recent paper, we described results of two double-blind investigations performed to examine effects of 100 microT(rms) 50 Hz MF exposure on psychological parameters in the same group of healthy human volunteers. In each exposure session, at 1 week intervals, with sham, continuous, and intermittent (15 s ON/OFF cycles) MF conditions, mood ratings, performance measures, and electrophysiological measures were taken. In the first study, significant amplitude changes were observed in the event-related brain potentials (ERP) recorded during a dichotic listening task. In the second study, latency and reaction time (RT) slowing were seen on a visual discrimination task (P(300) paradigm). Although these results were little related to the number of parameters analysed, they indicate that low level 50 Hz MF might have a slight influence on ERP and RT under specific circumstances of sustained attention. Before concluding that moderately strong MF exposure can influence cognitive function, previous results should be replicated, using the same paradigms with another group of healthy volunteers. In the present study, 18 healthy subjects were exposed to three experimental sessions of 30 min each, given at 1 week intervals. The sessions consisted of continuous 100 microT(rms) 50 Hz MF exposure, sham condition, and bright light (5000 lux) exposure. The study was performed double-blind, with the exposure order counter-balanced. The data on mood, ERP, RT, and other performance measures did not show any differences among the sham exposure, light exposure, and MF exposure conditions. The results of this study do not support the hypothesis that extremely low frequency (ELF) MF exposure affects the brain's electrical activity or cognitive function at field strength (100 microT(rms)) similar to that found in very close proximity of some household and industrial electrical appliances and well in excess of the average MF strength (c. 0.1 microT) found in homes. The sensitivity of the experiment was possibly not sufficient to detect an effect at this relatively low MF, and larger sample sizes would be required in further studies.
Marion Crasson; Jean-Jacques Legros
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Publication Detail:
Type:  Clinical Trial; Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Bioelectromagnetics     Volume:  26     ISSN:  0197-8462     ISO Abbreviation:  Bioelectromagnetics     Publication Date:  2005 Apr 
Date Detail:
Created Date:  2005-03-21     Completed Date:  2005-06-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8008281     Medline TA:  Bioelectromagnetics     Country:  United States    
Other Details:
Languages:  eng     Pagination:  225-33     Citation Subset:  IM    
Belgian BioElectroMagnetic Group, Psychoneuroendocrinology Unit, University of Liège, B-4000 Liège, Belgium.
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MeSH Terms
Brain / physiology,  radiation effects
Cognition / physiology*,  radiation effects*
Double-Blind Method
Electroencephalography / methods
Electromagnetic Fields*
Evoked Potentials / physiology*,  radiation effects*
Psychomotor Performance / physiology*,  radiation effects*
Reaction Time / physiology,  radiation effects

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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