Neuroscience Letters 397 (2006) 99–103 Acute mobile phone effects on pre-attentive operation Charalabos C. Papageorgiou a,c , Eleni D. Nanou b,∗ , Vassilis G. Tsiafakis b , E. Kapareliotis b , Kostantinos A. Kontoangelos a , Christos N. Capsalis b , Andreas D. Rabavilas c , Constantin R. Soldatos a a Department of Psychiatry, Eginition Hospital, University of Athens, Greece b National Technical University of Athens, Department of Electrical Engineering, Division of Information Transmission Systems and Material Technology, Greece c University Mental Health Research Institute, Athens, Greece Received 7 October 2005; received in revised form 28 November 2005; accepted 1 December 2005 Abstract There is a debate whether electromagnetic field (EMF) emitted by mobile phones (MP) have an effect on cognitive functions. Since the auditory P50 component of event-related potentials (ERPs) reflects pre-attentive processing and working memory (WM) operation, the present study was designed to investigate whether the exposure to MP-EMF affects the patterns of the P50 component of ERPs elicited during a WM test. The P50 elicited during a WM task and evoked by two warning stimuli low and high frequency (500 and 3000 Hz) has been assessed in 19 normal subjects (10 women and 9 men) both without and with exposure to a 900 MHz signal, emitted by a dipole antenna placed near the subjects. Results showed that the presence of MP-EMFs induced statistically significant increase in the amplitude of P50 evoked by the low frequency stimuli, at Fp1 and O1 electrode leads as compared to themselves without MP-EMF exposure. In contrast the exposure to MP-EMFs revealed statistically significant decrease of the amplitude of P50 evoked by the high frequency stimuli, at Fp1 electrode lead as compared to themselves without MP-EMF exposure. These findings provide evidence that the MP-EMF emitted by mobile phone affect pre-attentive information processing as it is reflected in P50 evoked potential. The basis of such an effect is unclear, although several possibilities exist and call for potential directions of future research. © 2005 Elsevier Ireland Ltd. All rights reserved. Keywords: Electromagnetic fields; Event-related potentials; Information processing; P50; Mobile phones; Working memory Mobile phone (MP) use is increasing rapidly. The use of MP emits electromagnetic field (EMF). The close proximity of a mobile phone to the user’s head leads to the absorption of part of the MP-EMF energy in the head and the brain [24]. This is especially important in view of the observation that the shape of the head is oval, with a short axis of 15–17 cm in length, which is half the wavelength of the 900 MHz transmission signals of the cellular phones. Consequently, the head may serve as a lossy res- onator absorbing much of the energy emitted by cellular phones [28]. Therefore, it is imperative to study the possible effects of MP-EMF on brain and behavior [29]. Event-related potentials due to their high resolution proper- ties can be of significant use in studying MP-EMF effects on brain activity [6]. There have been several studies of mobile phone emissions on the brain activity using the ERPs methodol- ∗ Corresponding author. Tel.: +30 210 7722574; fax: +30 210 7723520. E-mail address: enanou@mail.ntua.gr (E.D. Nanou). ogy with various results [5,7,14,22]. However, there have been few specifically examining the effect on the auditory system, which is strongly exposed to the produced EMF during the use of MP. The existing literature concerning the effects of MP-EMF on the auditory system is scarce and rather conflicting. Kellenyi et al. [10] showed that the latency of the fifth wave (V) of the audi- tory brainstem response (ABR) was significantly delayed after 15min of exposure to MP-EMF. On the other hand Arai et al. [1], showed no effects both on ABR (i.e. I, II, V waves) and the middle latency evoked brain response before and after using a MP (the usual Japanese MP emitting 800 MHz) for 30 min in 15 normal hearing volunteers. It should be noted that the earlier components of the ERPs are thought to represent the activity of the sensory pathways that transmit the signal generated at periph- eral receptors to central processing systems. These components are ‘modality specific’, that is they are influenced primarily by the stimulus parameters such as intensity and frequency [6]. Psychophysiological research suggested that the auditory P50 0304-3940/$ – see front matter © 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.neulet.2005.12.001