ID Number		980
Study Type		Human / Provocation
Model		Studies of RF signals (450 MHz) on human EEG and human nerves in situ.
Details		Human volunteers n=10 were exposed to 450 MHz (AM 7 Hz) RF with a reported field density a the scalp of 0.16 mW/cm2 (calculated SAR ~ 0.35 W/kg). Exposure did not result in any significant changes in VEP (visually evoked potentials), although the positive control caffeine did result in significant changes. In a related study, human volunteers were exposed to 450 MHz (AM 7 Hz) RF for ~20 minutes using a mobile phone transmitter with a 1 watt output at a calculated average brain SAR of ~0.35 W/kg. The exposure consisted of one cycle of photic stimulation with or without 10 cycles of repetitive RF stimulation. Combined photic + RF stimulation was reported to have consistent effects on alpha EEG rhythm. In a majority of cases, photic stimulation caused changes in the occipital region and RF stimulation in the frontal region of the brain. The effects varied from subject to subject, and the authors reported various alpha and theta EEG bands were decreased in a statistically significant manner. Preliminary studies showed the most effective modulation frequency for these changes was ~7 Hz, and effects at 6.5 and 7.5 Hz were not as pronounced. In a related study, the authors exposed additional volunteers (n = 23) as above and reported a decrease in low variability periods in exposed vs. sham individuals suggesting a mild effect. Additional studies on volunteers (n=13) were performed using 14 and 21 MHz modulated 450 MHz RF on EEG patterns for 4-10 minutes at an SAR of 0.35 W/kg. The authors report increased EEG average power using 14 and 21 Hz modulated 450 MHz in all subsets except theta bands, specifically in alpha, beta 1, and 2 bands. The effects was minimized during the couse of testing, which the authors interpret as adaption. In a related study (2008, 2009) the authors exposed subjects (n = 66) to 450 MHz RF modulated at 7 Hz, 7 and 21 Hz, 40 and 70 Hz, or 217 and 1000 Hz for 20 minutes at a calculated peak SAR of 0.303 W/kg. The authors report different inter-individual responses. The largest effect (increases in alpha and beta 1 spectral power) was observed using the 14 and 21 Hz modulated 450 MHz RF signal, but was also observed at higher modulation frequencies. Other studies, however, reported decreased alpha band EEG spectral power following 450 MHz exposure modulated at 14 Hz. The rate of individual responsiveness to RF was estimated ~13-30%. In a related study, patients (n = 18 women) with nonpsychotic major depressive disorder were exposed to 1000 MHz (PW, 50% duty cycle) for 30 minutes at 2 W/kg (calculated SAR). The authors report exposure resulted in positive mood improvement and effects on EEG that were not observed in non-depressed volunteers. AUTHORS' ABSTRACT: Hinrikus et al. 2016 (IEEE #6555): The aim of this study is to explain the mechanism of the effect of low-level modulated microwave radiation on brain bioelectrical oscillations. The proposed model of excitation by low-level microwave radiation bases on the influence of water polarization on hydrogen bonding forces between water molecules, caused by this the enhancement of diffusion and consequences on neurotransmitters transit time and neuron resting potential. Modulated microwave radiation causes periodic alteration of the neurophysiologic parameters and parametric excitation of brain bioelectric oscillations. The experiments to detect logical outcome of the mechanism on physiological level were carried out on 15 human volunteers. The 450-MHz microwave radiation modulated at 7, 40 and 1000 Hz frequencies was applied at the field power density of 0.16 mW/cm2. A relative change in the EEG power with and without radiation during 10 cycles was used as a quantitative measure. Experimental data demonstrated that modulated at 40 Hz microwave radiation enhanced EEG power in EEG alpha and beta frequency bands. No significant alterations were detected at 7 and 1000 Hz modulation frequencies. These results are in good agreement with the theory of parametric excitation of the brain bioelectric oscillations caused by the periodic alteration of neurophysiologic parameters and support the proposed mechanism. The proposed theoretical framework has been shown to predict the results of experimental study. The suggested mechanism, free of the restrictions related to field strength or time constant, is the first one providing explanation of low-level microwave radiation effects. AUTHORS' ABSTRACT: Bachmann, Hinrikus et al. 2018 (IEEE #7007): PURPOSE: This feasibility study is aimed to clarify the possibility of detection of microwave radiation (MWR)-induced event related potential (ERP) in electroencephalographic (EEG) signal. METHODS: To trigger onset and offset effects in EEG, repetitive MWR stimuli were used. Four 30-channel EEG recordings on a single subject were performed, each about one month apart. The subject was exposed to 450 MHz MWR modulated at 40 Hz at the 1 g peak spatial average specific absorption rate of 0.3 W/kg. During a recording, 40 cycles of 30 s on-off MWR exposure were used. The artifact-free responses to 126 MWR-ON stimuli and 134 MWR-OFF stimuli were averaged over stimuli and channels. RESULTS: Regarding EEG signals locked to MWR-OFF stimulus, the enhanced signal level at alpha frequency band and about twice higher signal to noise ratio at 200 to 440 ms after the stimulus have been detected. No remarkable response in EEG signals locked to MWR-ON stimulus. CONCLUSIONS: The detection of offset effect confirms that there should be an imprint generated by MWR in brain. The results of this preliminary study provide evidence for the detection of MWR-induced ERP in EEG signal and encourage further research in this direction.
Findings		Effects
Status		Completed With Publication
Principal Investigator		Tallinn Technical Univ, Tallinn Estonia
Funding Agency		EU, Sci Foundation, Estonia
Country		ESTONIA
References		Suhhova, A et al. Environmentalist., (2009) 29:210-214 Hinrikus, H et al. The Environmentalist, (2009) 29:215-219 Hinrikus, H et al. Bioelectromagnetics, (2008) 29:527-538 Bachmann, M et al. The Environmentalist, (2007) 27:505-510 Bachmann, M et al. Conf Proc IEEE Eng Med Biol Soc, (2006) 1:1597-1600 Hinrikus, h et al. Int J Radiat Biol, (2008) 84:69-79 Bachmann, M et al. Med Biol Engineering Computing, (2005) 43:142-149 Hinrikus, H et al. Bioelectromagnetics, (2004) 25:431-440 Hinrikus, H et al. Int J Radiat Biol. , (2011) 87:1077-1085 Suhhova, A et al. Bioelectromagnetics., (2013) 34:264-274 Hinrikus, H et al. Electromagn Biol Med., (2017) 36:202-212 Bachmann, M et al. Int J Radiat Biol. ;94(10):896-901, (2018) 94:896-901 Hinrikus, H et al. Int J Radiat Biol., (2021) 97:1505-1515 Gjoneska, B et al. Prilozi (Makedonska kademija na naukite i umetnostite Oddelenie za medicinski nauki)., (2015) 36:103-112 Hinrikus, H et al. Proceedings of the 25th Annual Conference of the IEEE EMBS, September 17-21, 2003., () :3253-3256 Hinrikus, H et al. Int J Radiat Biol., (2022) :1-11 Hinrikus, H et al. Int J Radiat Biol., (2018) 94:873-876
Comments		Insufficient details of exposure and dose assessment were provided. Instead of running control and exposed sessions in each individual, 5 of the 23 subjects were chosen for sham exposure, and no data on inter-individual variation was provided. The decrease in alpha band EEG is in contrast to many other RF bioeffect reports of increased alpha activity with MW stimulation. In the 2008 study, sham exposure was always first, and 7, 14, 21 Hz modulated 450 Mhz was in random order following sham exposures.