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Human exposure to power frequency magnetic fields up to 7.6 mT: An integrated EEG/fMRI study
Author(s) -
Modolo Julien,
Thomas Alex W.,
Legros Alexandre
Publication year - 2017
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.22064
Subject(s) - electroencephalography , bioelectromagnetics , eeg fmri , magnetic resonance imaging , functional magnetic resonance imaging , audiology , nuclear magnetic resonance , alpha (finance) , brain activity and meditation , medicine , neuroscience , psychology , nuclear medicine , physics , radiology , magnetic field , surgery , construct validity , quantum mechanics , patient satisfaction
We assessed the effects of power‐line frequency (60 Hz in North America) magnetic fields (MF) in humans using simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). Twenty‐five participants were enrolled in a pseudo‐double‐blind experiment involving “real” or “sham” exposure to sinusoidal 60 Hz MF exposures delivered using the gradient coil of an MRI scanner following two conditions: (i) 10 s exposures at 3 mT (10 repetitions); (ii) 2 s exposures at 7.6 mT (100 repetitions). Occipital EEG spectral power was computed in the alpha range (8–12 Hz, reportedly the most sensitive to MF exposure in the literature) with/without exposure. Brain functional activation was studied using fMRI blood oxygen level‐dependent (BOLD, inversely correlated with EEG alpha power) maps. No significant effects were detected on occipital EEG alpha power during or post‐exposure for any exposure condition. Consistent with EEG results, no effects were observed on fMRI BOLD maps in any brain region. Our results suggest that acute exposure (2–10 s) to 60 Hz MF from 3 to 7.6 mT (30,000 to 76,000 times higher than average public exposure levels for 60 Hz MF) does not induce detectable changes in EEG or BOLD signals. Combined with previous findings in which effects were observed on the BOLD signal after 1 h exposure to 3 mT, 60 Hz MF, this suggests that MF exposure in the low mT range (<10 mT) might require prolonged durations of exposure to induce detectable effects. Bioelectromagnetics. 38:425–435, 2017. © 2017 Wiley Periodicals, Inc.