Radiofrequency Electromagnetic Field Exposure and the Resting EEG: Exploring the Thermal Mechanism Hypothesis

Abstract

There is now strong evidence that radiofrequency electromagnetic field (RF-EMF) exposure influences the human electroencephalogram (EEG). While effects on the alpha band of the resting EEG have been repeatedly shown, the mechanisms underlying that effect have not been established. The current study used well-controlled methods to assess the RF-EMF exposure effect on the EEG and determine whether that effect might be thermally mediated. Thirty-six healthy adults participated in a randomized, double-blind, counterbalanced provocation study. A water-perfusion suit (34 C) was worn throughout the study to negate environmental influences and stabilize skin temperature. Participants attended the laboratory on four occasions, the first being a calibration session and the three subsequent ones being exposure sessions. During each exposure session, EEG and skin temperature (8 sites) were recorded continuously during a baseline phase, and then during a 30 min exposure to a 920 MHz GSM-like signal (Sham, Low RF-EMF (1 W/kg) and High RF-EMF (2 W/kg)). Consistent with previous research, alpha EEG activity increased during the High exposure condition compared to the Sham condition. As a measure of thermoregulatory activation, finger temperature was found to be higher during both exposure conditions compared to the Sham condition, indicating for the first time that the effect on the EEG is accompanied by thermoregulatory changes and suggesting that the effect of RF-EMF on the EEG is consistent with a thermal mechanism.

The Effect of GSM Electromagnetic Field Exposure on the Waking Electroencephalogram: Methodological Influences

“…Specifically, the first aim of the present study was to determine the importance of the choice of the eyes open versus eyes closed condition in the detection of RF-EMFrelated EEG alpha effects. Owing to the superior signal-to-noise ratio in the eyes open versus eyes closed condition (and in line with our previous work showing increased alpha due to RF-EMF exposure in the eyes open condition [Croft et al, 2002[Croft et al, , 2008[Croft et al, , 2010Loughran et al, 2019]), we hypothesized that EEG alpha power increase would be larger in the eyes open compared to the eyes closed resting condition. Secondly, we aimed to determine whether the effect of RF-EMF on the EEG alpha increase depends on exposure duration.…”

“…As described in Loughran et al [2019], resting EEG data were down-sampled to 500 Hz (125 Hz lowpass filter, 12 dB/oct), re-referenced to digitally linked mastoids, EOG corrected, and epoched into 2-s segments. Epochs were spline-fit to 512 points and baseline-corrected.…”

“…Planned contrasts (one-tailed) tested whether the global increase in EEG alpha power (i.e., ignoring the Laterality and Sagittality factors) during Exposure compared with Sham depended on Eye Condition, by considering the interaction term (which tested whether any effects of Exposure (Sham versus Low, and Sham versus High RF-EMF separately), were larger for the eyes open than closed condition. Global alpha was used because it is more reliably affected by RF-EMF exposure than localized scalp regions [Perentos et al, 2013;Loughran et al, 2019]; the factors were included within the analysis merely as a means of reducing error variance. For exploratory purposes, analyses were also performed to determine whether any effect of Eye Condition on the effect of Exposure interacted with topography.…”

Health-Related Electromagnetic Field Assessment in the Proximity of High Voltage Power Equipment

“…At the point where the maximum value of the longitudinal profile was found (usually at the middle of the opening where the lengths of conductors are on maximum), the profile of the structure is explored in a direction perpendicular to its longitudinal axis. This last exploitation leads to the identification of the maximum field point [14].…”

Special Issue: “Electric, Magnetic, and Electromagnetic Fields in Biology and Medicine: From Mechanisms to Biomedical Applications”

“…In Loughran et al [11], the influence of RF-EMF on electroencephalogram (EEG) readings was investigated in 36 healthy adults participating in a randomized, double-blind provocation study with the aim to find out if a thermal mechanism is involved in nervous system responses to RF-EMF. Indeed, the results suggest such an involvement.…”