Medical/biological study (experimental study)

Cognitive effects of radiation emitted by cellular phones: the influence of exposure side and time.

Published in: Bioelectromagnetics 2009; 30 (3): 198-204

Aim of study (acc. to author)

To examine time dependence effects of exposure to radiofrequency irradiation, emitted by GSM cellular phones, on cognitive functions of humans. The authors aimed to replicate and extend a previous study (publication 12887); especially to examine time-dependency and slowing of the left-hand response as results of the previous study.
Background/further details: 48 healthy males (right-handed) were divided into three groups: 1) exposure to the left side of the head, 2) exposure to the right side of the head, 3) sham exposure. All partcipants performed a spatial working memory task (that required either a left-hand or a right-hand response; 12 blocks of 50 trials). By averaging the reaction times separately for each block, the time course of the radiofrequency irradiation effect could be assessed.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 890.2 MHz
Exposure duration: 1 h
  • power: 2 W peak value
  • power: 0.25 W average over time
  • SAR: 0.54 W/kg minimum
  • SAR: 1.09 W/kg maximum
General information
three exposure conditions were tested: i) exposure at the left side of the head ii) exposure at the right side of the head iii) sham exposure
Exposure 1
Main characteristics
Frequency 890.2 MHz
Type
Exposure duration 1 h
Exposure setup
Exposure source/structure
Distance between exposed object and exposure source 1.5 cm
Setup details two standard Nokia 5110 GSM cellular phones attached to both sides of the head by a nonconductive frame
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Remarks
power 2 W peak value - -
power 0.25 W average over time - -
SAR 0.54 W/kg minimum - -
SAR 1.09 W/kg maximum - -
Exposed system:
  • human
  • partial body: head (left or right side)

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

During the first two time blocks, the average reaction time of the right-hand responses [matching condition] was significantly longer under left-side exposure than under right-side exposure and sham exposure averaged together. This result confirms an effect of exposure on reaction times. Left-hand responses [mismatching condition] showed the same pattern, but it was non-significant. The participants failed to judge which phone was operating during the experiment.
Although the present results confirmed some findings from the previous study (e.g. time dependency of reaction times), differences between the present results and previous findings may be due to the following factors: exposure duration, responding hand, side of exposure, and differences in the cognitive tasks. These factors may have major influence on the detection of radiofrequency irradiation effects.
Study character:
  • medical/biological study
  • experimental study
  • full/main study

Study funded by

  • not stated/no funding

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