19/02/2015
Inter-Individual and Intra-Individual Variation of the Effects of Pulsed RF EMF Exposure on the Human Sleep EEG
Caroline Lustenberger, Manuel Murbach, Laura Tüshaus, Flavia Wehrle, Niels Kuster, Peter Achermann, and Reto Huber, Bioelectromagnetics, Volume 36, Issue 3, pp. 169–177, April 2015, online February 17, 2015
Several studies have associated pulse-modulated radiofrequency electromagnetic fields (RF EMF) with brain activity during sleep. Typically, changes in the electroencephalographic (EEG) power were reported in the spindle frequency ranges (13.75–15.25 Hz) and delta-theta (1.25–9 Hz) frequency range. It is still unknown whether individual subjects react in a similar way when repeatedly exposed. Thus, our study aimed to investigate inter-individual variation and intra-individual stability of field effects. 20 young male volunteers were exposed twice for 30 min prior to sleep to the same amplitude modulated 900 MHz RF EMF signal. The RF exposure level was adjusted to a spatial peak specific absorption rate of 2 W/kg averaged over 10 g, and had a fundamental modulation frequency of 2 Hz, with suppressed harmonics above 50 Hz. The topographical analysis of EEG power during all-night non-rapid eye movement sleep revealed: (1) exposure-related increases in delta-theta frequency range in several fronto-central electrodes; and (2) no significant differences in spindle frequency range. We did not observe reproducible within-subject RF EMF effects on sleep spindle and delta-theta activity in the sleep EEG and it remains unclear whether a biological trait of how the subjects’ brains react to RF EMF exists.
The scientific and technical impact of the study can be summarized as:
- Further evidence of pulse-modulated RF EMF affecting brain physiology
- No evidence that some subjects are more susceptible/sensitive to RF EMF
- The biological relevance of the changes in the delta-theta range remains unknown.