The increasing number of telecommunication devices available and the length of time spent using mobile telephones has aroused interest for possible interactions between humans and radio-frequency (RF) radiations. It has been proposed that a precautionary principle should be adopted, particularly for children even if, at present, there is no convincing scientific data to recommend such a limited use of mobile phones.
In view of the proximity between radio-frequency source (i.e. mobile phones) and the human brain, several studies have investigated the effects of electromagnetic fields (EMFs) on resting cerebral activity, but results have often been contradictory.
A recent study, to be published in the next issue of Neuroscience Research, was conducted with the aim to test whether a global system for mobile communication (GSM) signal affects human resting EEG, analyzed with a high EEG frequency resolution, and, when this influence is most evident on EEG spectral power, i.e. whether this is restricted to the period of real exposure or if it continues after exposure cessation.
Researchers from Italy recorded the resting electroencephalogram of 20 healthy subjects in order to investigate the effect of EMF exposure on EEG waking activity and its temporal development. The subjects were randomly assigned to two groups and exposed, in double-blind conditions, to a typical mobile phone signal before or during the EEG recording session.
The results show that, under real exposure as compared to baseline and sham conditions, EEG spectral power was influenced in some bins of the alpha band. This effect was greater when the EMF was on during the EEG recording session than before it.
The authors conclude that EMFs like the ones emitted by mobile phones influence normal brain physiology, probably by means of changes in cortical excitability. However, the authors add that conclusions about possible health consequences are premature, particularly with respect to chronic and/or repeated exposures, and investigations on cell mechanisms are needed to better understand the macroscopic cerebral influences