Terrestrial Trunked Radio (TETRA) exposure and its impact on slow cortical potentials

Abstract

BackgroundStudies have shown that exposure to radiofrequency electromagnetic fields (RF-EMF) in the mobile communication frequency range may induce physiological modifications of both spontaneous as well as event-related human electroencephalogram. So far, there are very few peer-reviewed studies on effects of Terrestrial Trunked Radio (TETRA), which is a digital radio communication standard used by security authorities and organizations in several European countries, on the central nervous system. ObjectivesTo analyze the impact of simulated TETRA handset signals at 385MHz on slow cortical potentials (SCPs). Methods30 young healthy males (25.2±2.7 years) were exposed in a double-blind, counterbalanced, cross-over design to one of three exposure levels (TETRA with 10g averaged peak spatial SAR: 1.5W/kg, 6.0W/kg and sham). Exposure was conducted with a body worn antenna (especially designed for this study), positioned at the left side of the head. Subjects had 9 test sessions (three per exposure condition) in which three SCPs were assessed: SCP related to a clock monitoring task (CMT), Contingent negative variation (CNV) and Bereitschaftspotential (BP). ResultsNeither behavioral measures nor the electrophysiological activity was significantly affected by exposure in the three investigated SCP paradigms. Independent of exposure, significant amplitude differences between scalp regions could be observed for the CMT-related SCP and for the CNV. ConclusionsThe present results reveal no evidence of RF-EMF exposure-dependent brain activity modifications investigated at the behavioral and the physiological level.