Abstract—Mobile phone handsets such as those operating in the GSM network emit extremely low frequency electromagnetic fields ranging from DC to at least 40 kHz. As a subpart of an extended protocol, the influence of these fields on the human resting EEG has been investigated in a fully counter balanced, double blind, cross-over design study that recruited 72 healthy volunteers. A decrease in the alpha frequency band was observed during the 20 minutes of ELF exposure in the exposed hemisphere only. This result suggests that ELF fields as emitted from GSM handsets during the DTX mode may have an effect on the resting alpha band of the human EEG. I. INTRODUCTION HERE is ongoing concern regarding possible health and biological effects that can arise from the exposure of users to the electromagnetic emissions that personal telecommunication devices such as Global System for Mobiles (GSM) handsets emit. Investigations seem to detect biological effects associated with the exposure in equal frequency with investigations that do not. This fact combined with the absence of any acceptable physical mechanism that could explain any of the observed effects requires empirical tests of the possibility to continue. We have previously examined the effects of continuous and pulsed mobile phone like radiation on the human resting EEG [1], and so have many others [2]. One aspect of mobile phone exposure, which remains sidelined in current research in comparison to RF, is that caused by the Extremely Low Frequency (ELF) field which is produced by the flow of currents inside handset devices. The sole influence of this exposure on human brain variables has yet to be studied. Some relevant works are those that used real handsets for their investigations, and as such combine RF and ELF exposures. Examples are the works of Russel and Cosic [3], Curcio et al. [4], and Croft et al. [5], but are difficult to compare due to the combination of exposures. The works of Cook et al. are also relevant where changes in brain activity Manuscript received April 7, 2008. N. Perentos is with RMIT University, Melbourne, VIC 3000, Australia (phone: +61 4 2192 5572; fax: +61 3 9925 2954; e-mail: n.perentos@ student.rmit.edu.au). R. Croft is with Swinburne University, Melbourne, Australia (e-mail: RCroft@groupwise.swin.edu.au). R. McKenzie is with RMIT University, Melbourne, Australia (e-mail: Ray.McKenzie@rmit.edu.au). D. Cvetkovic is with RMIT University, Melbourne, Australia (e-mail: Dean.Cvetkovic@rmit.edu.au). I. Cosic is with RMIT University, Melbourne, Australia (e-mail: Irena.Cosic@rmit.edu.au). after and during exposure to pulsed ELF fields were observed [6, 7]. However, field characteristics in the works of Cook et al. significantly differed from those of mobile phones. Differences lie in the intensity, frequency content and spatial distribution of the fields. These characteristics have been studied by a few independent laboratories. The radiation is found to be spatially confined in close proximity to the source and spatial field decay is rapid, dropping significantly by the time it reaches the centre of the brain [8, 9]. The radiation dose associated with these ELF exposures has also been assessed and was found to be well below relevant exposure guidelines. So while technical and dosimetric aspects of the fields have been the subject of investigations it remains to determine whether they are capable of causing any measurable changes in brain variables. The statistical variation and contradictory nature of previous results in RF bioeffects literature can be avoided by employing robust experimental protocols. A similar approach was followed in our earlier study where we adjusted the experimental protocol accordingly, partly building on previous research, to avoid most methodological limitations. However one such limitation remained, that of small sample size, which led us to view those results with caution. In fact very few studies have used sample sizes greater than 30 and just two studies have recruited more than 50 volunteers [5, 10]. The significance of large samples is also stressed in a recent review by Valentini et al. [2]. To address this issue and the relative lack of large sample size studies we performed an extended double blind study where we recruited 72 healthy participants and studied their resting brain activity under three different electromagnetic radiations, pulse modulated RF, continuous RF and ELF fields. In this paper we present results pertaining to the ELF exposure, and specifically the resting brain activity in the alpha band region. II. MATERIALS AND METHODS A. Subjects Seventy two healthy volunteers (35 female and 37 male) participated in the study. The mean age of the sample was 24.5 years and the standard deviation was 5.4 years. Participants were instructed to abstain from alcohol The effect of GSM-like ELF radiation on the alpha band of the human resting EEG Nicholas Perentos, Rodney J. Croft, Raymond J. McKenzie, Dean Cvetkovic, and Irena Cosic, Senior Member, IEEE T 30th Annual International IEEE EMBS Conference Vancouver, British Columbia, Canada, August 20-24, 2008 978-1-4244-1815-2/08/$25.00 ©2008 IEEE. 5680 Authorized licensed use limited to: RMIT University. Downloaded on March 30,2010 at 18:53:23 EDT from IEEE Xplore. Restrictions apply.