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.
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.
|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.|
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.