Study type: Medical/biological study (experimental study)

The alpha band of the resting electroencephalogram under pulsed and continuous radio frequency exposures. med./bio.

Published in: IEEE Trans Biomed Eng 2013; 60 (6): 1702-1710

Aim of study (acc. to author)

To examine the effect of exposure to pulsed or continuous GSM-like electromagnetic fields on the resting EEG alpha wave activity in humans.

Background/further details

In many studies, indications of an effect of pulsed radiofrequency electromagnetic fields on the EEG have been found (for example Curcio et al. 2005, Croft et al. 2008).
72 healthy volunteers (35 females) were examined under: 1) sham exposure, 2) continuous radiofrequency exposure, 3) pulsed radiofrequency exposure and 4) pulsed extremely low frequency magnetic exposure. Participants attended a two hours recording session which included four 30 minutes intervals (four minutes break in between) where the order of exposure was counter balanced. In each 30 minutes interval, the first five minutes served as baseline, followed by 20 minutes exposure and five minutes post exposure period. Between the intervals, the arousal state was determined.

Endpoint

Exposure

Exposure Parameters
Exposure 1:
Modulation type: CW
Exposure duration: continuous for 3 x 20 min
  • SAR: 1.95 W/kg spatial average (10 g)
Exposure 2:
Modulation type: pulsed
Exposure duration: continuous for 3 x 20 min
  • SAR: 1.95 W/kg peak value
  • SAR: 0.06 W/kg
Exposure 3: 2.1–217 Hz
Exposure duration: continuous for 3 x 20 min

General information

Participants were exposed in 4 times 20 min sessions with a 4 min break between exposures: 1) sham exposure 2) continuous RF exposure 3) pulsed RF exposure 4) ELF exposure

Exposure 1

Main characteristics
Frequency
Type
Exposure duration continuous for 3 x 20 min
Modulation
Modulation type CW
Exposure setup
Exposure source
  • specially designed handset
Chamber handset was placed in ear-to-mouth position (held via a cradle), over the right hemisphere; speaker and antenna located over the auditory canal; another handset (not radiating), but otherwise identical, placed on the left side of the head
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 1.95 W/kg spatial average - 10 g -

Exposure 2

Main characteristics
Frequency
Type
Exposure duration continuous for 3 x 20 min
Modulation
Modulation type pulsed
Additional info

GSM-DTX signal

Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 1.95 W/kg peak value - - -
SAR 0.06 W/kg - - - -

Exposure 3

Main characteristics
Frequency 2.1–217 Hz
Type
Waveform
Exposure duration continuous for 3 x 20 min
Additional info GSM-DTX-like pulsing
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 25 µT peak value - - at the front surface of the handset
eddy current density 7.77 µA/m² spatial average calculated - -

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)

Exposure to pulsed radiofrequency electromagnetic fields significantly changed the alpha wave activity when compared to sham exposure. However, no significant differences were found between the exposure to pulsed and continuous radiofrequency fields, where a slight but not significant difference in the EEG was found in comparison to sham exposure.
Compared to sham exposure, no significant effect of pulsed extremely low frequency magnetic exposure on the EEG activity was observed.
The results indicate that the alpha waves of the resting EEG are altered by radiofrequency electromagnetic fields, but do not support the hypothesis that the pulsing is essential for this effect.

Study character:

Study funded by

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