Radio frequency electromagnetic field exposure in humans: Estimation of SAR distribution in the brain, effects on sleep and heart rate

Abstract

In two previous studies we demonstrated that radiofrequency electromagnetic fields (RF EMF) similar to those emitted by digital radiotelephone handsets affect brain physiology of healthy young subjects exposed to RF EMF (900 MHz; spatial peak specific absorption rate [SAR] 1 W/kg) either during sleep or during the waking period preceding sleep. In the first experiment, subjects were exposed intermittently during an 8 h nighttime sleep episode and in the second experiment, unilaterally for 30 min prior to a 3 h daytime sleep episode. Here we report an extended analysis of the two studies as well as the detailed dosimetry of the brain areas, including the assessment of the exposure variability and uncertainties. The latter enabled a more in depth analysis and discussion of the findings. Compared to the control condition with sham exposure, spectral power of the non-rapid eye movement sleep electroencephalogram (EEG) was initially increased in the 9-14 Hz range in both experiments. No topographical differences with respect to the effect of RF EMF exposure were observed in the two experiments. Even unilateral exposure during waking induced a similar effect in both hemispheres. Exposure during sleep reduced waking after sleep onset and affected heart rate variability. Exposure prior to sleep reduced heart rate during waking and stage 1 sleep. The lack of asymmetries in the effects on sleep EEG, independent of bi- or unilateral exposure of the cortex, may indicate involvement of subcortical bilateral projections to the cortex in the generation of brain function changes, especially since the exposure of the thalamus was similar in both experiments (approx. 0.1 W/kg).

Dosimetric evaluation and comparison of different RF exposure apparatuses used in human volunteer studies

“…The model is based on a data set of the head of a healthy female subject (aged 40 years), consisting of 121 magnetic resonance images (MRI), with a slice separation of 1 mm in the ear region and 3 mm for the rest of the head [Burkhardt and Kuster, 2000]. During the MRI scans, the pinna of the ear was [Haarala et al, 2003[Haarala et al, , 2004[Haarala et al, , 2005[Haarala et al, , 2006 Swinburne Setup [Loughran et al, 2005] Zurich Setup [Huber et al, 2000[Huber et al, , 2002[Huber et al, , 2003[Huber et al, , 2005Regel et al, 2006Regel et al, , 2007 Huber et al [2000Huber et al [ , 2002Huber et al [ , 2003Huber et al [ , 2005; Regel et al [2007] Set for psSAR10g b ¼ 0.2 and 5 W/kg in Regel et al [2006] a Power control level (PCL), corresponding to a nominal output power of 33dBm AE4 dB [ETSI-3GPP, 2005]. Note that for most phones the actual input power is towards the lower end of the accepted range.…”

“…The latter was motivated by the hypothesis that sub-cortical regions (including the thalamus) may contain the structures most sensitive to RF EMF. Because the EEG effect did not depend on the side of exposure [Huber et al, 2000[Huber et al, , 2003 it was hypothesized that bilateral cortical projections from sub-cortical structures may explain the absence of a hemispheric asymmetry. For validation, the same phantoms as defined for compliance testing [IEC, 2007] were used, that is, a flat phantom, and the specific anthropomorphic mannequin (SAM).…”

“…In the past, the selected exposure source for human volunteer studies ranged from placing an active mobile phone next to a bed [Mann and Roschke, 1996], resulting in poorly defined low-level exposure, to very controlled exposures explicitly designed for health risk assessment studies [Huber et al, 2000[Huber et al, , 2003.…”

“…The objective of this report is to provide detailed dosimetry for the exposure setups based on a modified commercial NOKIA 6110 mobile phone used in several studies at the University of Turku (Turku Setup) [Haarala et al, 2003[Haarala et al, , 2004[Haarala et al, , 2005[Haarala et al, , 2006 and at Swinburne University (Swinburne Setup) [Loughran et al, 2005] and compare the data with the setup applied in the studies at the University of Zurich (Zurich Setup) [Huber et al, 2000[Huber et al, , 2002[Huber et al, , 2003[Huber et al, , 2005Regel et al, 2006Regel et al, , 2007.…”

Mobile phones and sleep - A review

“…Huber et al [8] reported an extended analysis of the two studies as well as the detailed dosimetry of the brain areas, including the assessment of the exposure variability and uncertainties. The latter enabled a more in depth analysis and discussion of the findings.…”