Study type: Medical/biological study (experimental study)

Pulsed radio frequency radiation affects cognitive performance and the waking electroencephalogram. med./bio.

Published in: Neuroreport 2007; 18 (8): 803-807

Aim of study (acc. to author)

To study the effects of radiofrequency electromagnetic fields on brain physiology. The effects of a pulse modulation and a continuous wave radiofrequency exposure on cognitive performance and the waking EEG were compared.

Background/further details

During exposure (pulse modulation, continuous wave, or sham exposure), 24 participants performed cognitive tasks. EEG was recorded during baseline (before exposure), immediately after, and 30 and 60 min after exposure.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 30 min
  • SAR: 1 W/kg peak value (10 g) (spatial peak)
Exposure 2: 900 MHz
Modulation type: CW
Exposure duration: continuous for 30 min
  • SAR: 1 W/kg peak value (10 g) (spatial peak)

General information

Three experimental conditions (PW, CW, and sham) were applied at weekly intervals in a double-blind, randomized, counterbalanced crossover design.

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 30 min
Modulation
Modulation type pulsed
Pulse width 0.577 ms
Duty cycle 12.5 %
Additional info

GSM handset frame structure (4.6 ms) with one slot active and modulation components of 2, 8, 217, 1733 Hz, and higher harmonics [Huber et al., 2005]

Exposure setup
Exposure source
Distance between exposed object and exposure source 115 mm
Setup The subject's head was positioned between two planar patch antennas and was exposed unilaterally on the left hemisphere. The center of the antenna was located 42 mm vertically above the ear canal at a distance of 115 mm from the head [Huber et al., 2003].
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 1 W/kg peak value - 10 g spatial peak

Exposure 2

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 30 min
Modulation
Modulation type CW
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 1 W/kg peak value - 10 g spatial peak

Reference articles

  • Huber R et al. (2005): Exposure to pulse-modulated radio frequency electromagnetic fields affects regional cerebral blood flow.
  • Huber R et al. (2003): Radio frequency electromagnetic field exposure in humans: Estimation of SAR distribution in the brain, effects on sleep and heart rate.

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Pulse modulated radiofrequency exposure reduced reaction speed and increased accuracy in a working memory task. It also increased spectral power in the EEG in the 10.5-11 Hz range (alpha wave activity) 30 min after exposure.
No effects were found for continuous wave radiofrequency exposure.
These data provide further evidence for a nonthermal biological effect of pulsed radiofrequency fields. The underlying physiological mechanisms remain unknown. Thus, the effects have to be interpreted cautiously, in particular, with respect to possible health consequences.

Study character:

Study funded by

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