Effect of a 915-MHz simulated mobile phone signal on cognitive function inman

Purpose: To examine whether a simulated mobile telephone transmission at 91 5 MHz has an effect on cognitive function in man. Materials and methods: Thirty-six subjects in two groups were each given tw o training sessions and then three test sessions in a randomized three-way cross-over design. About 1 W mean power at 915 MHz from a quarter-wave ante nna mounted on a physical copy of an analogue phone, as a sine wave, or mod ulated at 217 Hz with 12.5% duty cycle, or no power, was applied to the lef t squamous temple region of the subjects while they undertook a series of c ognitive function tests lasting similar to 25-30 min. The second group was investigated for sleep, consumption of alcohol and beverages, and any other substances that might affect performance. Results: In both groups, the only test affected was the choice reaction tim e and this showed as an increase in speed (a decrease in reaction time). Th ere were no changes in word, number or picture recall, or in spatial memory . While an effect of visit-order was evident suggesting a learning effect o f repeat tests, the design of the study allowed for this. Additionally, the re was no systematic error introduced as a result of consumption of substan ces or sleep time. Conclusions: There was evidence of an increase in responsiveness, strongly in the analogue and less in the digital simulation, in choice reaction time . This could be associated with an effect on the angular gyrus that acts as an interface between the visual and speech centres and which lies directly under and on the same side as the antenna. Such an effect could be consist ent with mild localized heating, or possibly a non-thermal response, which is nevertheless power-dependent.