Study type: Medical/biological study (experimental study)

Human Postural Responses to High Vestibular Specific Extremely Low-Frequency Magnetic Stimulations. med./bio.

Published in: IEEE Access 2020; 8: 165387-165395

Aim of study (acc. to author)

The effects of exposure of the human vestibular organ to a low frequency magnetic field or current on postural control should be investigated.

Background/further details

A total of 38 healthy participants were examined in this randomized crossover study. The following conditions were investigated: 1) exposure to a magnetic field, 2) alternating current stimulation, 3) direct current stimulation (positive control), 4) no stimulation (negative control). The stimulations in groups 1 and 2 were applied with different frequencies: a) 20 Hz, b) 60 Hz, c) 90 Hz, d) 120 Hz and e) 160 Hz.
Postural control is the ability of the human body to maintain an upright body position. In a previous study by Villard et al. (2018), no effects of exposure of the vestibular organ to a low frequency magnetic field on postural control were found. However, this field had a vertical orientation, so in the present study a horizontal orientation of the magnetic field was investigated.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 20–160 Hz
Exposure duration: 5 seconds per condition per trial
Exposure 2: 20–160 Hz
Exposure duration: 5 seconds per condition per trial
  • 2 mA

Exposure 1

Main characteristics
Frequency 20–160 Hz
Type
Exposure duration 5 seconds per condition per trial
Exposure setup
Exposure source
Setup headset coil exposure system (6.70 kg) consisting of two 570 turn-coils of 5.9 cm of mean diameter, with a 2.5-cm diameter core of Permendur-49; the two coils were bound together to a custom adjustable headset to fit participants’ heads; although only the right vestibular organ was stimulated, both were kept together to prevent any postural bias due to asymmetrical load; the whole headset was suspended by a rod system, tied to a vest worn around participants’ chests to unload the weight of the coils as they were maintained on the participants’ head; subjects wore earplugs throughout the experiment to conceal the noise generated by the coils
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 100 mT effective value - - at 3 cm from the coils where the vestibular organ approximately lies
magnetic flux density 141.42 mT peak value - - at 3 cm from the coils where the vestibular organ approximately lies

Exposure 2

Main characteristics
Frequency 20–160 Hz
Type
Exposure duration 5 seconds per condition per trial
Exposure setup
Exposure source
Setup transcranial current stimulation device (StarStim, Neuroelectrics, Spain) with circular 25 cm2 Ag/AgCl electrodes; the magnetic field headset exposure system was set over the StarStim exposure cap; both the StarStim cap and the magnetic field exposure device were kept on the head during all testing conditions
Parameters
Measurand Value Type Method Mass Remarks
cf. remarks - peak value - - 2 mA

Reference articles

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 vestibular organ to a low frequency magnetic field or current on postural control were found.

Study character:

Study funded by

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