Sauter C, Dorn H, Bahr A, Hansen M-L, Peter A, Bajbouj M, Danker-Hopfe H. Effects of exposure to electromagnetic fields emitted by GSM 900 and WCDMA mobile phones on cognitive function in young male subjects. Bioelectromangetics. 28 OCT 2010. Ahead of print.
Many studies have been conducted on possible effects of radiofrequency electromagnetic fields (RF EMFs) on neurobehavioral outcomes. Most of these studies examined the effects of Global System for Mobile Communication (GSM)-like signals, and the results of these studies are inconsistent. Little information is available on the effects of Wideband Code-Division Multiple Access/3rd Generation Universal Mobile Telecommunications System (WCDMA/3G UMTS) signals on cognitive function.
The objective of the study was to examine possible effects of GSM 900 and WCDMA/3G UMTS on attention and working memory in a randomized double-blind cross-over study.
Thirty healthy male volunteers 18-30 years of age were tested on nine study days separated by 2-week intervals. They were exposed to three conditions (sham, GSM900 and WCDMA/3GUMTS) in a randomly assigned and balanced order three days per condition for 7 hours and 15 minutes per day. Cognitive tests were administered twice on each exposure day, in the morning and in the afternoon. Different aspects of attention (divided attention, selective attention and vigilance) and working memory were evaluated.
Divided attention: Under WCDMA exposure, a slight but statistically significant increase in reaction time to visual stimuli was observed in the morning. Statistical significance disappeared after correction for multiple testing. On the contrary, in the afternoon, mean reaction time decreased (non-significantly) compared to sham exposure. Selective attention: No effect of any type of exposure was observed either on reaction time or on the number of correct reactions in the morning or in the afternoon. Vigilance: Higher number of correct reactions and shorter reaction times were seen under GSM exposure compared to sham in the morning. The same tendency was observed for the number of correct reactions under WCDMA exposure. These results were no longer significant after adjustment for multiple testing. No significant time-of-day effect was seen. Working memory: No significant effect of GSM or WCDMA exposure was seen either in the morning or in the afternoon. There was a significant time-of-day effect: after correction for multiple testing, shorter reaction times were seen in the afternoon than in the morning under GSM exposure.
Interpretation and Conclusion
The results were inconsistent in terms of the direction of the observed effects showing both improvements and deteriorations. Statistical significance of most effects disappeared after correction for multiple testing. The authors assumed that there was no effect of RF EMF exposure on the examined cognitive domains. Effect of time-of-day was more consistent, indicating the need to control for this parameter in studies of RF effects on cognitive functions.