To establish a dose-response relationship between the field strength of electromagnetic fields and previously reported effects (see "Related articles") on the brain, the authors aimed to investigate the influence of electromagnetic field exposure by varying the signal intensity (0.2 W/kg; 5 W/kg; sham exposure).
The heads of 15 healthy male subjects was unilaterally exposed for 30 min prior to sleep. During exposure subjects performed cognitive tasks. Immediately after exposure, night-time sleep was polysomnographically recorded for 8 h.
The study consisted of three sessions separated by 1-week intervals in a randomized double-blind crossover design. Each session consisted of an adaptation night and a subsequent experimental night.
|Exposure duration||continuous for 30 min|
|Setup||Subjects were exposed unilaterally (left hemisphere) with their heads positioned between two plates to ensure a well-defined position with respect to the planar antennas [Huber et al., 2000, 2003].|
|Sham exposure||A sham exposure was conducted.|
Sleep architecture was not affected by electromagnetic field exposure. The sleep EEG revealed a dose-dependent increase of power in the spindle frequency range in non-REM sleep.
Reaction speed decreased with increasing field strength in the 1-back task, while accuracy in the 2-choice reaction time task and N-back task were not affected in a dose-dependent manner.
In conclusion, the data revealed first indications of a dose-response relationship between electromagnetic field intensity and its effects on brain physiology.