Influence of short-term exposure of magnetic field on the bioelectrical processes of the brain and performance.

The influence of an extremely-low-frequency (ELF) magnetic field on the bioelectrical processes of brain and performance was studied by EEG spectral analysis, auditory-evoked potentials (AEP), reaction time (RT) and target-deletion test (TDT). Fourteen volunteers were exposed for 15 min to an intermittent (1 s on/off) 45-Hz magnetic field at 1000 A/m (1.26 mT). Each person received one real and one sham exposure. Statistically significant increases in spectral power through alpha- and beta-bands, as well as in mean frequency of the EEG spectrum were observed after magnetic field exposure. Field-dependent changes of N100 were also revealed. No changes in the amplitudes or latencies of the earlier peaks were observed. No direct effects on RT, nor on TDT performance were seen. However, practice effects on RT (decrease of RT in the course of the test-sessions) seemed to be interrupted by exposure to the magnetic field.