Study type: Medical/biological study (experimental study)

Effects of information and 50 Hz magnetic fields on cognitive performance and reported symptoms med./bio.

Published in: Bioelectromagnetics 2007; 28 (1): 53-63

Aim of study (acc. to author)

The objective of this study was to explore the role of expectancies and beliefs about the potential effects of electromagnetic fields and the effects of 50 Hz magnetic fields acute exposure on cognitive performance, the reporting of physical symptoms and some psychological and physiological parameters.

Background/further details

74 male subjects were randomly assigned to one of five groups, which differed in (1) the type of information they were given concerning the expected magnetic field effect on performance in cognitive tests (positive = enhancement of the performance; negative = impairment of the performance; neutral) and (2) the type of exposure (real or sham exposure). Three groups were sham-exposed with positive (group+), negative (group-) and neutral information (group+/-); one group was really exposed with neutral information (exposure group) and one group was not exposed, they did not receive any field-related information (control group). All the subjects, except the control group, were led to believe that they would be exposed to a magnetic field of 400 µT.



Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 30 min

Exposure 1

Main characteristics
Frequency 50 Hz
  • unspecified
Exposure duration continuous for 30 min
Additional info vertical magnetic field.
Exposure setup
Exposure source
Setup The subjects wore a magnetic helmet for exposing the head to a homogeneous 50 Hz MF. The helmet is a cubic structure formed by six Helmholtz coils distributed in three orthogonal directions. There was no perceptible warming nor noise under experimental conditions.
Sham exposure A sham exposure was conducted.
Additional info All volunteers except the ones in the control group were led to believe that they would be exposed to MF but just one group was exposed.
Measurand Value Type Method Mass Remarks
magnetic flux density 400 µT effective value unspecified - -

Reference articles

  • Crasson M et al. (1999): 50 Hz magnetic field exposure influence on human performance and psychophysiological parameters: two double-blind experimental studies

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)

No significant difference was found among the five groups depending on the type of information and the type of exposure in cognitive performance, psychological and physiological parameters. The type of information given failed to induce expected changes in parameters measured.

Study character:

Study funded by

Related articles