Study type: Medical/biological study (experimental study)

Radiofrequency signal affects alpha band in resting electroencephalogram. med./bio.

Published in: J Neurophysiol 2015; 113 (7): 2753-2759

Aim of study (acc. to author)

The effects of exposure of subjects to a 900 MHz electromagnetic field (GSM) on the brain activity should be investigated in a resting EEG.

Background/further details

26 subjects (13 male, 13 female) participated in 2 sessions, respectively: exposure and sham exposure. Each session was divided into a pre-exposure part, an exposure/sham exposure part and a post-exposure part. During each part, the resting EEG with open eyes and with closed eyes was measured repeatedly in separate runs for 3 minutes per run, respectively. Two runs were measured during the pre- and post-exposure parts, respectively, and 3 runs were measured during the exposure/sham exposure part.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 26 minutes
  • power: 2 W peak value
  • power: 250 mW mean
  • SAR: 0.49 W/kg maximum (10 g)
  • SAR: 0.7 W/kg maximum (1 g)
  • SAR: 0.93 W/kg peak value

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 26 minutes
Additional info GSM
Modulation
Modulation type pulsed
Duty cycle 12.5 %
Exposure setup
Exposure source
Chamber dimly lit, electrically shielded room
Setup mobile phone was positioned against the left ear of subject and connected to a PC to control exposure; subjects were seated in a comfortable chair and a screen was placed in front of them to keep their eyes in a well-defined direction; interference of EEG electrodes with mobile phone was controlled; electrode impedance was controlled
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power 2 W peak value - - -
power 250 mW mean - - -
SAR 0.49 W/kg maximum measured 10 g -
SAR 0.7 W/kg maximum measured 1 g -
SAR 0.93 W/kg peak value measured - -

Reference articles

  • Ghosn R et al. (2012): Effects of GSM 900 MHz on middle cerebral artery blood flow assessed by transcranial Doppler sonography.

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

During the exposure and post-exposure part, the alpha wave power was significantly decreased in the EEG with closed eyes in the exposure session compared to the sham exposure session. All other parameters did not show any significant differences between exposure and sham exposure.
The authors conclude that exposure to a 900 MHz electromagnetic field (GSM) might influence alpha waves in the resting EEG and thus the brain activity.

Study character:

Study funded by

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