Study type: Medical/biological study (experimental study)

Effects of electromagnetic field emitted by cellular phones on the EEG during a memory task. med./bio.

Published in: Neuroreport 2000; 11 (4): 761-764

Aim of study (acc. to author)

To assess the possible effects of electromagnetic field exposure on human brain electric oscillatory activity during an auditory memory task with words as stimuli.

Background/further details

The authors focused on event related desynchronisation (ERD) and synchronisation (ERS) (ERD/ERS is a pattern in the EEG signal, that shows functional alterations of neuronal networks) of the 4-6 Hz, 6-8 Hz, 8-10 Hz and 10-12 Hz narrow EEG frequency bands. EEG frequencies are subdivided into frequency bands. The simultaneously recorded responses of different EEG frequency bands differ from each other and reflect different cognitive and/or mental processes.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 902 MHz
Modulation type: pulsed
Exposure duration: continuous for 30 min

Exposure 1

Main characteristics
Frequency 902 MHz
Type
Exposure duration continuous for 30 min
Modulation
Modulation type pulsed
Pulse width 0.557 ms
Repetition frequency 217 Hz
Additional info

Pulse width is probably a misprint instead of 0.577 ms.

Exposure setup
Exposure source
Distance between exposed object and exposure source 20 mm
Chamber The subject was seated in a comfortable chair in a dimmed registration room and was instructed to look at a TV screen placed 1.5 m in front of him/her and to avoid unnecessary eye movements.
Setup A standard GSM phone was mounted to the subject's head over the right posterior temporal region in a normal use position. The antenna was located about 20 mm from the head. The phone was operated via a computer from an adjacent room.
Additional info Each EEG test session was subdivided into two segments, with or without EMF in single-blind, counterbalanced order. The total testing time was about 60 min.
Parameters
Measurand Value Type Method Mass Remarks
power 0.25 W mean - - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The radiation to electromagnetic fields significantly increased EEG power in the 8-10 Hz frequency band only. Nonetheless, the presence of electromagnetic fields altered the ERD/ERS responses in all studied frequency bands as a function of time and memory task. The results suggest that the radiation to electromagnetic fields does not alter the resting EEG per se but modifies the brain responses during a memory task.

Study character:

Study funded by

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