Study type: Medical/biological study (experimental study)

Resting EEG effects during exposure to a pulsed ELF magnetic field. med./bio.

Published in: Bioelectromagnetics 2005; 26 (5): 367-376

Aim of study (acc. to author)

To study the effects of pulsed extremely low frequency magnetic fields on the human EEG during the exposure period.

Background/further details

In a previous study it was shown that after a 15 min exposure to a pulsed extremely low frequency magnetic field, with most power at frequencies between 0 and 500 Hz, human brain electrical activity is affected, specifically within the alpha waves frequency (8-13 Hz) (see publication 10628).

Endpoint

Exposure

Exposure Parameters
Exposure 1:
  • unspecified
Modulation type: pulsed
Exposure duration: 15 min

Exposure 1

Main characteristics
Frequency
  • unspecified
Type
Waveform
Exposure duration 15 min
Modulation
Modulation type pulsed
Additional info

853 ms segment consisting of 18 pulses with each pulse having a maximum rise of 1 ms. Each pattern consised of a pulse segment followed by varying refractory periods of 110, 220, 330 ms plus a constant fourth period of 5000 ms after which another pulse segment (853 ms) was delivered. This pattern was repeated for 15 min.

Exposure setup
Exposure source
Setup Subjects were seated in the exposure system consisting of three orthogonal square coils with only the vertical coil pair powered.
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 200 µT peak value unspecified - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Occipital alpha waves activity (8-13 Hz) decreased during exposure to a pulsed extremely low frequency magnetic field compared to sham exposure. This effect was revealed after the first 5 min of a 15 min irradiation and was dependent on the magnetic field/sham order of exposure. This decrease was no longer significant in the first minute post-exposure, compared to sham exposure.
(Discrepancies between the current results and the data of the previous study suggest that the EEG changes may be sensitive to the characteristics of the magnetic field pulse train).

Study character:

Study funded by

Replication studies

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