Three conditions were examined: "control", "noise", and "magnetic field". The "noise" condition represented the sham exposure, because generation of the magnetic field was also accompanied by noise.
In total, 66 subjects were examined. Thirty-six subjects were exposed to the "control" condition and to the "magnetic field" (or vice versa). The remaining 30 subjects were exposed to the "control" condition and to the "noise" condition (or vice versa). There was a one hour break between the two conditions.
Subjects were divided into sensitive and non-sensitive to electromagnetic fields according to their own ratings.
Exposure duration: 1 hour
|Chamber||wooden cabin in a transformer station|
|Setup||subjects were seated in a wooden cabin, which was placed at a distance from a transformer coil, so that the magnetic field was approximately 1 mT in the head region; magnetic field exposure was accompanied with noise of about 45 dB; temperature was 21°C and humidity circa 48%|
|Sham exposure||A sham exposure was conducted.|
|Additional info||control condition: background magnetic field was less than 3 µT and noise less than 28 dBA; noise condition: background field was less than 3 µT and noise about 45 dB as in magnetic field condition|
|magnetic flux density||1 mT||-||-||-||at the head ± 10%|
No significant differences were found in the comparison of the conditions "control" versus "noise". Significant differences were found in the "magnetic field" condition when compared to the "control". The exposed subjects had a lowered attention, perception and memory performance. Significant differences were also found in the comparison of the "magnetic field" condition versus the "noise" condition: The memory performance and the perception were significantly decreased and more discomfort was observed. Including the self-rated sensitivity of the probands into the statistical analysis, led to even more pronounced effects in subjects rated as sensitive to electromagnetic fields but diminished the effects in non-sensitive subjects.
The authors suggest that the data indicate a reduction of cognitive performance in attention, perception and memory performance by a 50 Hz magnetic field which seems to be influenced by the self-perception of sensitivity to electromagnetic fields.