Study type: Medical/biological study (experimental study)

Human Postural Control Under High Levels of Extremely Low Frequency Magnetic Fields med./bio.

By: Bouisset N, Villard S, Legros A
Published in: IEEE Access 2020; 8: 101377-101385
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Aim of study (acc. to author)

The effects of exposure of the human head to extremely low frequency magnetic fields on postural control should be investigated.

Background/further details

Four types of stimulations and a negative control were presented to 20 participants in a random order: 1) exposure to a 20 Hz magnetic field, 2) exposure to a 60 Hz magnetic field, 3), exposure to a 90 Hz magnetic field, 4) DC stimulation (positive controll) and 5) no stimulation (negative control).
Postural control is the ability of the human body to maintain an upright body position. In an earlier studie (Glover et al. 2007), no effect of an extremely low frequency magnetic field of 2 T/s on human postural control was found, but it was hypothesized that a stimulation with more than 4 T/s should be able to evoke an effect. This hypothesis was investigated in the present study.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 20 Hz
Exposure duration: 5 seconds
Exposure 2: 60 Hz
Exposure duration: 5 seconds
Exposure 3: 90 Hz
Exposure duration: 5 seconds

Exposure 1

Main characteristics
Frequency 20 Hz
Type
Exposure duration 5 seconds
Exposure setup
Exposure source
Setup head coil exposure system consisting of a pair of 99-turn coils (11 layers of 9 turns each, 35.6 cm inner diameter and 50.1 cm outer diameter) made of hollow square copper wire cooled by circulating water; the two coils were assembled into a Helmholtz-like configuration, spaced 20.6 cm from center to center; the participants' ears were centered between the coils; field was vertically orientated and homogeneous at the location of the participants' head; to conceal the noise generated by the coils, subjects wore earplugs throughout the experiment
Additional info a direct current stimulation was delivered using a transcranial direct current stimulation device as positive control
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 50 mT - measured and calculated - equates to 8.89 T/s

Exposure 2

Main characteristics
Frequency 60 Hz
Type
Exposure duration 5 seconds
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 50 mT - measured and calculated - equates to 26.66 T/s

Exposure 3

Main characteristics
Frequency 90 Hz
Type
Exposure duration 5 seconds
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 50 mT - measured and calculated - equates to 39.98 T/s

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

No effects of exposure of the human head to extremely low frequency magnetic fields on postural control were found.

Study character:

Study funded by

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