Study type: Medical/biological study (experimental study)

High Frequency GSM-1800 Fields with Various Modulations and Field Strengths: No Short Term Effect on Human Awake EEG med./bio.

By: Hinrichs H, Heinze HJ
Published in: Edition Wissenschaft 2006; 23: 1-12
Journal not peer-reviewed
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Aim of study (acc. to author)

To study the influence of modulation and field strength of electromagnetic fields according to the GSM 1800 standard on short-term EEG alterations.

Background/further details

27 healthy subjects were studied. For each of them five short EEG epochs (each four minutes; 3.5 minutes break in between) were recorded under exposure. Due to artefacts or vigilance fluctuations, only data from 18 subjects (11 female) were evaluated.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1,800 MHz
Modulation type: CW
Exposure duration: intermittent, 4 min on/3.5 min off, for each condition
  • power: 0.25 W peak value
  • power: 0.25 W mean
  • SAR: 1.22 W/kg average over mass (10 g)
  • SAR: 2.28 W/kg average over mass (1 g)
Exposure 2: 1,800 MHz
Modulation type: pulsed
Exposure duration: intermittent, 4 min on/3.5 min off, for each condition
  • power: 2 W peak value
  • power: 0.25 W mean
  • SAR: 1.22 W/kg average over mass (10 g)
  • SAR: 2.28 W/kg average over mass (1 g)
Exposure 3: 1,800 MHz
Modulation type: pulsed
Exposure duration: intermittent, 4 min on/3.5 min off, for each condition
  • power: 1 W peak value
  • power: 0.125 W mean
  • SAR: 0.61 W/kg average over mass (10 g)
  • SAR: 1.14 W/kg average over mass (1 g)
Exposure 4: 1,800 MHz
Modulation type: pulsed
Exposure duration: intermittent, 4 min on/3.5 min off, for each condition
  • power: 2 W peak value
  • power: 0.125 W mean
  • SAR: 0.61 W/kg average over mass (10 g)
  • SAR: 1.14 W/kg average over mass (1 g)
Exposure 5: 1,800 MHz
Modulation type: pulsed
Exposure duration: intermittent, 4 min on/3.5 min off, for each condition
  • power: 8 W peak value
  • power: 0.125 W mean
  • SAR: 0.61 W/kg average over mass (10 g)
  • SAR: 1.14 W/kg average over mass (1 g)

General information

Following a 6-min adaptation period, EEG recordings of 4 min were made for each of six exposure conditions, including sham, that were separated by breaks of 3.5 min. The sequence of conditions was randomised over subjects in double blind mode.

Exposure 1

Main characteristics
Frequency 1,800 MHz
Type
Exposure duration intermittent, 4 min on/3.5 min off, for each condition
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 10 mm
Chamber EEG recordings were performed in a separate room, the walls of which were coated with RF-absorbing foam elements with an attenuation of at least 20 dB at 1-2 GHz. The bioamplifier was positioned outside this room.
Setup Subjects were seated in a wooden desk chair in a relaxed wakefulness with eyes closed. The mobile phone was attached to the frame of the chair and was individually positioned with its antenna close to the subject's ear.
Sham exposure A sham exposure was conducted.
Additional info The orientation and position of the antenna approximately matched the 30° position as specified in the measurement standard drafted by CENELEC, SC211/B, WGMTE (1997).
Parameters
Measurand Value Type Method Mass Remarks
power 0.25 W peak value measured - -
power 0.25 W mean measured - -
SAR 1.22 W/kg average over mass measured 10 g -
SAR 2.28 W/kg average over mass measured 1 g -
Measurement and calculation details

Signal characteristics were continuously controlled with the aid of an output monitor included in the test generator. The corresponding SAR values were assessed in a separate study (IMST, 1998) with an anatomically realistic full scale head phantom.

Exposure 2

Main characteristics
Frequency 1,800 MHz
Type
Exposure duration intermittent, 4 min on/3.5 min off, for each condition
Modulation
Modulation type pulsed
Repetition frequency 217 Hz
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power 2 W peak value measured - -
power 0.25 W mean measured - -
SAR 1.22 W/kg average over mass measured 10 g -
SAR 2.28 W/kg average over mass measured 1 g -

Exposure 3

Main characteristics
Frequency 1,800 MHz
Type
Exposure duration intermittent, 4 min on/3.5 min off, for each condition
Modulation
Modulation type pulsed
Repetition frequency 217 Hz
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power 1 W peak value measured - -
power 0.125 W mean measured - -
SAR 0.61 W/kg average over mass measured 10 g -
SAR 1.14 W/kg average over mass measured 1 g -

Exposure 4

Main characteristics
Frequency 1,800 MHz
Type
Exposure duration intermittent, 4 min on/3.5 min off, for each condition
Modulation
Modulation type pulsed
Repetition frequency 108 Hz
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power 2 W peak value measured - -
power 0.125 W mean measured - -
SAR 0.61 W/kg average over mass measured 10 g -
SAR 1.14 W/kg average over mass measured 1 g -

Exposure 5

Main characteristics
Frequency 1,800 MHz
Type
Exposure duration intermittent, 4 min on/3.5 min off, for each condition
Modulation
Modulation type pulsed
Repetition frequency 27 Hz
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power 8 W peak value measured - -
power 0.125 W mean measured - -
SAR 0.61 W/kg average over mass measured 10 g -
SAR 1.14 W/kg average over mass measured 1 g -

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

During the four minute exposures under various modulations and field strengths no short-term alterations of the EEG were observed. None of the subjects experienced any remarkable sensations during exposure.
In this study, no evidence for an athermic biological effect of GSM electromagnetic fields on awake EEG was found.

Study character:

Study funded by

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