Study type: Medical/biological study (experimental study)

Effects of GSM electromagnetic field on the MEG during an encoding-retrieval task med./bio.

By: Hinrichs H, Heinze HJ
Published in: NeuroReport 2004; 15 (7): 1191-1194
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Aim of study (acc. to author)

To study potential effects of GSM 1800 electromagnetic fields on verbal memory encoding by recording event-related magnetic fields from the brain (electrocortical magnetic fields caused by sensory, motor, or psychic events; measured via MEG) during subsequent memory retrieval.

Background/further details

After encoding words from a study list presented in the first phase (under exposure) subjects had to discriminate old from new words mixed together in a test list presented during the second phase (without exposure).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1.87 GHz
Modulation type: pulsed
Exposure duration: continuous for 30 min
  • power: 1 W peak value
  • power: 0.25 W average over time
  • SAR: 0.61 W/kg average over mass (10 g) (according to CENELEC standard)
  • SAR: 1.14 W/kg average over mass (1 g) (according to ANSI norm)

Exposure 1

Main characteristics
Frequency 1.87 GHz
Type
Exposure duration continuous for 30 min
Additional info Reference article: Institut für Mobil- und Satellitenfunktechnik (IMST), Kamp-Lintfort/Germany: Dosimetrische Vermessung von DCS 1800-Mobiltelefonen. Technical report 1998.
Modulation
Modulation type pulsed
Repetition frequency 217 Hz
Exposure setup
Exposure source
Chamber The subjects were seated in a wooden chair in the center of a chamber (2 x 1.8 x 2 m) the walls of which were covered by foam pads preventing reflections.
Setup A GSM like signal was generated by a signal generator and fed to the antenna of a mobile phone which was located close to the left ear of the subjects in the 30° position according to CENELEC.
Additional info Each subject performed the experiment twice with either EMF or sham exposure (double blind) on separate days.
Parameters
Measurand Value Type Method Mass Remarks
power 1 W peak value measured - -
power 0.25 W average over time measured - -
SAR 0.61 W/kg average over mass estimated 10 g according to CENELEC standard
SAR 1.14 W/kg average over mass estimated 1 g according to ANSI norm
Measurement and calculation details

The field strength, modulation and homogeneity were checked before the start by means of a spectrum analyser. The field power was continuously monitored by a field power sensor. The SAR was estimated in a separate simulation study (see reference article).

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Exposure to electromagnetic fields changed an early (350-400 ms) task-specific component of the event-related magnetic fields indicating an interference of electromagnetic fields and item encoding. Behavioural measures (reaction times, the rate of correctly detected new and correctly identified old words) were not significantly affected. Adverse health effects cannot be derived from these results.

Study character:

Study funded by

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