12/04/2011
Sleep EEG Alterations: Effects of Different Pulse-Modulated Radio Frequency Electromagnetic Fields
Marc R. Schmid, Sarah P. Loughran, Sabine J. Regel, Manuel Murbach, Aleksandra Bratic Grunauer, Thomas Rusterholz, Alessia Bersagliere, Niels Kuster, and Peter Achermann, Journal of Sleep Research, Volume 21, Issue 1, pp. 50–58, February, 2012, online April 12, 2011
Previous studies have observed increases in EEG power during sleep in the spindle frequency range (approx. 11–15 Hz) after RF EMF exposure synthesizing GSM conditions. This study investigated whether pulse-modulation frequency components in the range of sleep spindles may be involved in mediating these effects. 30 young healthy men were exposed, at weekly intervals, to 3 different conditions for 30 min directly prior to an 8-h sleep period. Exposure consisted of a 900-MHz RF EMF, pulse modulated at 14 Hz or 217 Hz (psSAR of 2 W/kg), and a sham control condition. During exposure, subjects performed three different cognitive tasks (measuring attention, reaction speed and working memory), which were presented in a fixed order. EEG power in the spindle frequency range was increased during non-rapid eye movement sleep (2nd episode) following the 14-Hz pulse-modulated condition. A similar but non-significant increase was also observed following the 217-Hz pulse-modulated condition. Importantly, this exposure-induced effect showed considerable individual variability. Regarding cognitive performance, no clear exposure-related effects were seen. Consistent with previous findings, the results provide further evidence that pulse-modulated RF EMF alter brain physiology, although the time-course of the effect remains variable across studies. Additionally, we demonstrated that modulation frequency components within a physiological range may be sufficient to induce these effects.
