Monday, February 23, 2015

Radiofrequency signal affects alpha band in resting electroencephalogram

Joel's comments: This study found a lasting reduction in the spectral power of the alpha band in participants when their eyes closed during and after exposure to GSM cell phone radiation. Although the authors suggest this may be a beneficial effect, this interpretation is open to debate. 

More importantly, this study demonstrates as several previous studies have (e.g., Volkow et al, 2011) that short-term exposure to legal (non-thermal) levels of cell phone radiation generated by commercially-available cell phones affects human brain activity. 
ICNIRP guidelines and FCC standards were designed only to prevent thermal effects under the assumption that exposure to sub-thermal levels of cell phone radiation could not have produce bioeffects. The results of studies like this one have shifted the debate to one where industry must now argue that the observed bioeffects produced by short-term exposures are not harmful to human health over the long term. However, the epidemiologic research is increasingly demonstrating that this assumption is false. At least three independent case-control studies have found that long term exposure to cell phone radiation is associated with increased brain tumor risk. 


Radiofrequency signal affects alpha band in resting electroencephalogram

Ghosn R, Yahia-Cherif L, Hugueville L, Ducorps A, Lemarechal JD, Thuroczy G, de Seze R, Selmaoui B. Radiofrequency signal affects alpha band in resting electroencephalogram. J Neurophysiol. 2015 Feb 18:jn.00765.2014. doi: 10.1152/jn.00765.2014. [Epub ahead of print]


Objective: The aim of the present work was to investigate the effects of the radiofrequency (RF) electromagnetic fields (EMFs) on human resting EEG with a control of some parameters that are known to affect alpha band such as electrode impedance, salivary cortisol and caffeine.

Methods: Eyes open and eyes-closed resting EEG data were recorded in 26 healthy young subjects under two conditions: sham exposure and real exposure in double-blind, counterbalanced, crossover design. Spectral power of EEG rhythms was calculated for the alpha band (8-12Hz). Saliva samples were collected before and after the study. Salivary cortisol and caffeine were assessed respectively by Enzyme linked immunosorbent assay (ELISA) and high performance liquid chromatography (HPLC). The electrode impedance was recorded at the beginning of each run.

Results: Compared with sham session, the exposure session showed a statistically significant (p < 0.0001) decrease of the alpha band spectral power during closed eyes condition. This effect persisted in the post-exposure session (p < 0.0001). No significant changes were detected in electrode impedance, salivary cortisol and caffeine in the sham session when compared to the exposure one.

Conclusions: These results suggest that GSM-EMFs of a mobile phone affect alpha band within spectral power of resting human EEG.


Some earlier studies have investigated the effects of EMFs on resting cerebral activity with somewhat mixed results, but more recently there has been consistent data indicating the existence of exposure effects on the alpha bands of the resting EEG ...

As the literature cited demonstrates, the most consistent effect observed is a change in alpha band power. However, these changes sometimes correspond to an increase in alpha power and sometimes to a decrease. The reason why alpha band power reacts differently to RF exposure remains unclear. The main problem lies in the use of different methods, different experimental protocols and/or different intensities or frequencies (van Rongen 74 et al. 2009), thus making the comparison of data more difficult. As also reported by Loughran et al. (2012), individual variability is also one of the important factors that may explain the discrepancies between the results ...

The aim of the present study was to examine the potential impact of GSM (global system for mobile) RF (radiofrequency) exposure to the alpha band of the resting EEG under controlled parameters and to thus bring additional information to fill certain gaps in our current knowledge of the effects of GSM RF exposure ...

During each session, the subject was exposed to 26 min 15 s of sham or real GSM RF exposure (Fig. 1). In the case of sham exposure, the mobile phone was switched ‘‘on’’ but without RF radiation, while for real exposure, the mobile phone was switched ‘‘on’’ with RF radiation. For the same subject, the two sessions were at a one-week interval. Both the subjects and experimenters were unaware of the exposure condition.

Subjects were exposed to RF EMF by a commercial dual band GSM mobile phone (Nokia 154 6650). The mobile phone was positioned against the left ear. To set the standard exposure parameters, the phone was connected to a personal computer to control the required frequency and RF power by service software ... double-blind protocol ....

... The participants received GSM modulated exposure with the full power of the mobile phone (2 W peak, 250 mW average, pulse modulated with 1/8 duty cycle) at 900 MHz for 26 min. The maximum specific absorption rates (SARs) were averaged on 10 g tissue, 1 g tissue, and the peak value was measured at 0.49 W/kg, 0.70 W/kg and 0.93 W/kg, respectively. The SAR of the ‘‘sham’’ phone was below the detection level of the system (0.001 W/kg) at any position of the phantom, and no electric field was detected on the surface of the ‘‘sham’’ phone (for more details see: Ghosn et al. 2012).

... Results showed that alpha spectral power decreased during exposure period to GSM signals. These results concur with previous findings on the effects of GSM signals on alpha power of resting EEG in humans (Croft et al. 2002; Kramarenko and Tan 2003; Curcio et al. 2005). When analyzing lower (8-10 Hz) and upper (10-12 Hz) alpha bands separately, results showed a similar significant decrease. This effect persisted in the post-exposure period (Table 1), suggesting that the effect is sustained with lasting physiological changes and not solely 308 during immediate interaction between exposure and the target tissue. This is in line with the results obtained in other studies that have exposed participants prior to the EEG recording (Reiser et al. 1995; Huber et al. 2002; Curcio et al. 2005), and where an effect of RF-EMF has been observed on brain activity. The persisted effect of RF-EMF on brain activity was also observed on the EEG during sleep in where some authors have reported a modification following the active period of exposure (Loughran et al. 2005; Regel et al. 2007; Loughran et al. 2012).

According to these data, it seems that the effects observed in our study mimic, to some extent, the global reductions in alpha-band power observed in eyes-opened versus eyes-closed conditions. One would suggest that the power decrease in alpha band frequency resulting from the GSM signal exposure could be beneficial for memory process, global attention and cognitive performance. The potential clinical significance of this effect, in this area, could be assessed in further studies

... Our results showed no significant variations in salivary cortisol between sham and real exposure.

Exposure to GSM-EMFs of a mobile phone can influence human dominant alpha rhythms in a resting state. Our results showed a power decrease of alpha band during and after exposure to GSM-EMFs compared with sham exposure in an eyes-closed condition. These findings were not correlated with impedance electrodes, cortisol or caffeine, factors that can influence alpha power. However, extended post-exposure duration should be tested since the observed effect persisted until the end of the post-exposure period. Furthermore, it is also important to stress the potential clinical significance of this effect.


Joel M. Moskowitz, Ph.D., Director
Center for Family and Community Health
School of Public Health
University of California, Berkeley

Electromagnetic Radiation Safety

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