Medical/biological study (experimental study)

Effects of exposure to electromagnetic fields emitted by GSM 900 and WCDMA mobile phones on cognitive function in young male subjects.

Published in: Bioelectromagnetics 2011; 32 (3): 179-190

Aim of study (acc. to author)

To study possible effects of long-term electromagnetic field exposure to mobile phone handset-like signals (GSM and W-CDMA) on attention and working memory in 30 healthy male subjects (18-30 years old).
Background/further details: The subjects were tested on nine study days (separated by two week intervals) in which they were exposed to three exposure conditions (sham exposure, GSM and W-CDMA) in a randomly assigned and balanced order. All tests were presented twice (morning and afternoon) on each study day within a fixed timeframe.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Exposure duration: 3 days (à 7 h 15 minutes), separated by at least two week intervals
Distinction: GSM
Exposure 2: 1,966 MHz
Exposure duration: 3 days (à 7 h 15 minutes), separated by 2-week intervals and not necessarily consecutive
Distinction: WCDMA/3G UMTS
General information
9 study days (separated by 2-week intervals) with randomly assigned continuous exposure (sham exposure, GSM 900 and WCDMA/3G UMTS, 3 days each, not necessarily consecutive)
Exposure 1
Main characteristics
Frequency 900 MHz
Type
Exposure duration 3 days (à 7 h 15 minutes), separated by at least two week intervals
Distinction GSM
Exposure setup
Exposure source/structure
Chamber details examination room with low background fields
Sham exposure A sham exposure was conducted.
Additional information antenna connected to a thin microwave RF coaxial cable; antenna designed like in cell phones
Parameters
Measurand Value Type Method Remarks
power 1 W - - input power
SAR 7.82 W/kg - measured and calculated -
Measurement and calculation details
field distribution was simulated and measured in a phantom filled with head tissue-equivalent liquid; SAR measurements made with a DASY 4 measurement system
Exposure 2
Main characteristics
Frequency 1,966 MHz
Exposure duration 3 days (à 7 h 15 minutes), separated by 2-week intervals and not necessarily consecutive
Distinction WCDMA/3G UMTS
Exposure setup
Exposure source/structure
Parameters
Measurand Value Type Method Remarks
power 1 W - - input power
SAR 10.98 W/kg - measured and calculated -
Exposed system:
  • human
  • partial body: head

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)

Univariate comparison (t-test or Wilcoxon test) revealed significant changes when subjects were exposed to GSM exposure (higher number of correct reactions and shorter reaction time in the morning trial) compared to sham exposure, only in the vigilance test. In the W-CDMA exposure condition, one parameter in the vigilance (higher number of correct reactions) and one in the test on divided attention (slower reaction time in the morning session) were altered compared to sham exposure. Performance in the selective attention test and the n-back task was not affected by GSM or W-CDMA exposure. Time-of-day effects were evident for the tests on divided and selective attention, as well as for working memory.
After correction for multiple testing (Bonferroni inequality), only time-of-day effects remained significant in two tests, resulting in faster reactions in the afternoon trials.
The authors conclude, that the data do not provide any evidence of an electromagnetic field effect on human cognition, but they underline the necessity to control the paramter time-of-day.
Study character:
  • medical/biological study
  • experimental study
  • full/main study

Study funded by

  • Bundesamt für Strahlenschutz (BfS; Federal Office for Radiation Protection), Salzgitter, Germany
  • Deutsches Mobilfunk Forschungsprogramm (DMF; German Mobile Phone Research Programme) at Federal Office for Radiation Protection (BfS)

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