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Thresholds for 60 Hz magnetic field stimulation of peripheral nerves in human subjects
Author(s) -
Bailey William H.,
Nyenhuis John A.
Publication year - 2005
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.20106
Subject(s) - bioelectromagnetics , rheobase , magnetic field , nuclear magnetic resonance , pulse (music) , population , coronal plane , peripheral , physics , electric field , biomagnetism , stimulation , biomedical engineering , anatomy , medicine , optics , environmental health , quantum mechanics , detector
The goal of the research reported here is to narrow the range of uncertainty about peripheral nerve stimulation (PNS) thresholds associated with whole body magnetic field exposures at 50/60 Hz. This involved combining PNS thresholds measured in human subjects exposed to pulsed magnetic gradient fields with calculations of electric fields induced in detailed anatomical models of the body by that same exposure system. PNS thresholds at power frequencies (50/60 Hz) can be predicted from these data due to the wide range of pulse durations (70 μs to 1 ms), the length of the pulse trains (several tens of ms), and the exposure of a large part of the body to the magnetic field. These data together with the calculations of the rheobase electric field exceeded in 1% (E 1% ) of two anatomical body models, lead to a median PNS detection threshold of 47.9 ± 4.4 mT for a uniform 60 Hz magnetic field exposure coronal to the body. The threshold for the most sensitive 1% of the population is about 27.8 mT. These values are lower than PNS thresholds produced by magnetic fields with sagittal and vertical orientations or nonuniform exposures. Bioelectromagnetics 26:462–468, 2005. © 2005 Wiley‐Liss, Inc.