Human resting-state EEG and radiofrequency GSM mobile phone exposure: the impact of the individual alpha frequency

Abstract

Purpose. With the extensive use of mobile phone (MP) several studies have been realized to investigate the effects of radiofrequency electromagnetic fields (RF-EMF) exposure on brain activity at rest via electroencephalography (EEG), and the most consistent effect has been seen on the alpha band power spectral density (PSD). However, some studies reported an increase or a decrease of the PSD, while others showed no effect. It has been suggested that these differences might partly be due to a variability of the physiological state of the brain between subjects. So, the aim of this study was to investigate the alpha band modulation, exploring the impact of the alpha band frequency ranges applied in the PSD analysis.Materials & Methods. Twenty-one healthy volunteers took part to the study with a doubleblind, randomized and counterbalanced crossover design, during which eyes-open (EO) and eyes-closed (EC) resting-state EEG was recorded. The exposure system was a sham or a real GSM (global system for mobile) 900 MHz MP (pulse modulated at 217 Hz, mean power of 250 mW and 2 W peak, with a maximum specific absorption rate of 0.70 W/kg on 1 g tissue).The experimental protocol presented a baseline recording phase without MP exposure, an exposure phase during which the exposure system was placed against the left ear, and the postexposure phase without MP. EEG data from baseline and exposure phases were analyzed and PSD was computed for the alpha band in the fixed range of 8-12 Hz and for the individual alpha band frequency range (IAF).Results. Results showed a trend in decrease or increase of EEG power of both alpha oscillations during exposure in relation to EC and EO recording conditions, respectively, but not reaching statistical significance. Findings did not provide evidence for a different sensitivity to RF-EMF MP related to individual variability in the frequency of the alpha band. Conclusion.In conclusion, these results did not show alpha band activity modulation during resting-state under RF-EMF. It might be argued the need of a delay after the exposure in order 3 to appreciate an EEG spectral power modulation related to RF-EMF exposure.

Theta band brainwaves in human resting EEG modulated by mobile phone radiofrequency

“…The real MP was set to transmit a modulated 900 MHz GSM signal (peak 2 W, average 250 mW, pulse modulated with a duty cycle of 1/8) at its maximum power using a service software (Phoenix, Nokia Corp., Finland). Further details about the RF-EMF exposure setup are available elsewhere (Wallace et al, 2022).…”

“…Results showed that MPs did not affect EEG signals during the exposure. Further details about dosimetry and phantom assessment are described elsewhere (Ghosn et al, 2015;Wallace et al, 2022).…”

“…This study is part of the broad study published previously (Wallace et al, 2022). A double-blind, randomized, counterbalanced, crossover design was employed where each volunteer underwent two experimental sessions one week apart at the same time of day to avoid circadian rhythm bias.…”

Effects of mobile phone electromagnetic fields on brain waves in healthy volunteers

“…But this approach may come at the cost of introducing additional variation between the sham and RF on conditions, making it more difficult to detect the actual EMF effect. Indeed, in quite some studies with a counterbalanced design no effects in the alpha band were reported 11 , 12 , 26 .…”

“…An essential strand within the literature on detecting the biological effects of EMF in vivo consists of studies that utilize the electroencephalogram (EEG) to record potential EMF induced alterations in the brain's electrical activity. Commonly, the brain is either assessed during rest, with resting-state EEG, or during specific tasks 11 , 12 , with event-related EEG 13 , 14 , while the participants are exposed to EMF. A session with EMF dosage and another session without EMF form the basis protocol for the experimental comparison to show the potential presence of EMF effects on the brain.…”