Time-course of electromagnetic field effects on human EEG and performance.

The present study was aimed to investigate the time-course of GSM-induced effects on EEG, cognitive and behavioral performances. Twenty subjects were randomly assigned to two experimental groups: in the first, subjects were exposed for 45 min before the recording session (“before”); in the other condition subjects were exposed during the recording (“during”). Each subject was sub- mitted to a baseline (BSL), a real exposure (ON session) and a sham exposure (OFF session), according to a double-blind design. Resting EEG, reaction times, cognitive and attentional tasks, and tympanic temperature were collected during the recording sessions. The tympanic temperature was significantly higher for the exposed ear, indicating a local heating. No effects were found on cognitive and vigilance tasks. The results of ANOVAs on reaction times (RTs) showed a significant effect: ON sessions showed shorter RTs as compared to both BSL and OFF conditions. Moreover, a significant effect for the Group factor indicated that the “before” group had faster RTs than the “during” group. The EEG spectral power showed comparable effects on Fz, Cz, Pz and T3 derivations, indicating more marked EEG changes under the electromagnetic field exposure. These findings point to a clear time course of the effects induced by electromagnetic field on human EEG and performances.