Study type: Medical/biological study (experimental study)

Human exposure to power frequency magnetic fields up to 7.6 mT: An integrated EEG/fMRI study. med./bio.

Published in: Bioelectromagnetics 2017; 38 (6): 425-435

Aim of study (acc. to author)

To investigate the effects 60 Hz magnetic fields on the human brain activity.

Background/further details

Subjects were divided in two groups: Group 1 (n=13, 5 males and 8 females) were first exposed to a 3 mT magnetic field (12 x 10 seconds) while EEG signals were recorded and the fMRI images were taken (respectively 8 images after the 10 seconds of exposure). Afterwards, they were exposed to a magnetic field with 7.6 mT (100 x 2 seconds with 2 seconds rest between) while only EEG signals were recorded. Group 2 (n=12, 5 males and 7 females) was subjected to the same procedure except they were sham exposed instead of the 3 mT magnetic field.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 60 Hz
Exposure duration: intermittent 12 x for 10 seconds
Exposure 2: 60 Hz
Exposure duration: intermittent 100 x for 2 seconds

Exposure 1

Main characteristics
Frequency 60 Hz
Type
Waveform
Exposure duration intermittent 12 x for 10 seconds
Additional info subjects wore earplugs to reduce noises produced by the MRI scanner, and also to prevent them from hearing the sound produced by the MRI scanner during the 60 Hz MF exposure; subjects were equipped with an EEG cap and with a pulse oximeter on the index finger
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 3 mT - - - first exposure

Exposure 2

Main characteristics
Frequency 60 Hz
Type
Waveform
Exposure duration intermittent 100 x for 2 seconds
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 7.6 mT - - - second exposure

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

No significant effects were found between EEG signals of exposed and sham exposed subjects or between exposure condition and post-exposure condition. Furthermore, no significant effects between exposure and sham exposure were found in the brain activity examined with fMRI. Similar levels of comfort or stress were reported in both groups while no magnetophosphene perception was reported.
The authors conclude that acute exposure to a 60 Hz magnetic field of 3 to 7.6 mT does not induce detectable changes in the human brain activity assessed by EEG and fMRI.

Study character:

Study funded by

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