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Effects of extremely low‐frequency magnetic field exposure on cognitive functions: results of a meta‐analysis
Author(s) -
Barth Alfred,
Ponocny Ivo,
PonocnySeliger Elisabeth,
Vaorbert,
Winker Robert
Publication year - 2010
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.20543
Subject(s) - bioelectromagnetics , meta analysis , cognition , sample size determination , flexibility (engineering) , statistical analysis , psychology , statistical power , audiology , statistics , cognitive psychology , magnetic field , mathematics , medicine , physics , neuroscience , pathology , quantum mechanics
There is extensive literature on possible effects of extremely low‐frequency magnetic fields (ELF‐MFs) on human cognitive functions. However, due to methodological deficits (e.g., low statistical power, small sample sizes) findings have been inconsistent. In the current study we try to overcome these problems by carrying out a meta‐analysis. Literature research revealed 17 studies. Nine of these were included in the meta‐analysis because they fulfilled minimum requirements (e.g., at least single‐blind experimental study design and documentation of means and standard deviation of the dependent variables). All of the studies used a 50 Hz magnetic field exposure. Small but significant effect sizes could be detected in two cognitive dimensions: in the hard level of visual duration discrimination, task‐exposed subjects performed better than controls; at the intermediate level however, exposed subjects performed worse. Additionally, a significant improvement of correct responses was observed in the dimension of “flexibility” under exposure. However, due to the small number of studies per performance dimensions and the resulting instability of estimates, these findings have to be treated with extreme caution. Taken together, the results of the meta‐analysis provide little evidence that ELF‐MFs have any effects on cognitive functions. Bioelectromagnetics 31:173–179, 2010. © 2009 Wiley‐Liss, Inc.