Affective response to 5 µT ELF magnetic field‐induced physiological changes

Abstract

Research into effects of weak magnetic fields (MFs) at biologically relevant frequencies has produced ambiguous results. Although they do affect human physiology and behaviour, the direction of effects is inconsistent, with a range of complex and unrelated behaviours being susceptible. A possible explanation is that these effects, rather than being directly caused, are instead related to changes in affective state. A previous study showed that MFs altered the affective content of concurrent perceptions, but it was unclear whether the emotional response was direct or indirect. Here it is shown that exposure to a 0-5 microT MF (DC-offset sinudsoidal wave form) within EEG alpha-band frequencies (8-12 Hz), results in a reported change in emotional state. This relates to a decrease global field power but lacks the frontal alpha-asymmetry that would physiologically indicate a directly induced emotional state, suggesting that participant experiences are due to an interpretation of the effects of MF exposure.

The Alpha Band of the Resting Electroencephalogram Under Pulsed and Continuous Radio Frequency Exposures

“…Some relevant studies to which our results can be compared are those of Cook et al [19]- [20] which employed exposures that bear some spectral resemblance to those employed here (pulsed ELF exposures but with homogeneous exposure properties), and they reported both increases and decreases of alpha activity during and shortly after exposure. In addition Stevens reported a decrease of alpha activity after exposure to weak magnetic fields [28]. Given that our results were not consistent with any of these suggests that either their results were spurious, or that the particular ELF modulation is crucial for affecting neural function.…”

“…It should be noted that the observed decrease in alpha is not in line with the prevailing trend of RF-induced increases in alpha activity [2]- [4], [10]. However, given that alpha changes in the literature are typically global and not localized to regions with the highest SAR, it has been suggested that the alpha change may represent an indirect effect of exposure, such as a higher level change to neural processing [28], thus leaving room for the intermediate processes to interfere with the direction of the alpha change. In addition, the current findings cannot be explained by an alpha rebound effect whereby the alpha would decrease during exposure and, consistent with literature, increase after exposure.…”

Alterations of human electroencephalographic activity caused by multiple extremely low frequency magnetic field exposures

“…The consistent results with our study were also reported in another study with a decrease in the alpha (8-13 Hz) EEG activity at the occipital region after 2-s MF exposure of 0-60 Hz/ 20-100 lT [2]. Another study revealed a decrease in global field power and no indication in any frontal alpha asymmetry [ratio of right (F4) and left (F3) frontal powers] [20]. Our future analysis could perhaps employ similar method such as the EEG hemispheric asymmetry of anterior-posterior (A-P) regions and inter/intra hemispheric coherence.…”

“…These results were contradictory with our pilot study [8], but consistent with many other previous studies [4,5] on EEG responses, which revealed that the alpha activity was significantly higher over the occipital region, and marginally higher over the parietal electrodes at 15-min post exposure. The other consistencies in the alpha band increase at MF exposure compared to MF control were also reported in the following studies: a decrease in the delta (1-3 Hz) and theta (4-7 Hz) (frontal/central/parietal regions) and an increase in the alpha (7-13 Hz) and beta (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) in the respective occipital and frontal regions (45-Hz MF) [14]; an increase in the alpha (10 Hz) EEG activity at the central region after 10-min MF exposure of 10 Hz/40 lT and 1.5 Hz/20 lT [3]; an increases in the spectral power mainly at higher than 10 Hz EEG frequencies at the central, parietal and occipital regions due to 2-s light and EMF exposures to 80 lT/1.5 Hz and 10 Hz [15]; and a significant increase in the alpha (8-13 Hz) EEG activity over occipital region due to a 90 min MF exposure 50 Hz/80 lT [11].…”

“…Over the last two decades, several ELF studies have claimed that MF exposure characteristics could alter the human EEG activity, as follows: a sinusoidal 60-min intermittent MF exposure of 45 Hz and 1.26 mT [14]; a 2-s MF exposure of 60 Hz/20-100 lT [2]; 2-s epochs exposed to MF exposure of 10 Hz/40 lT and 1.5 Hz/20 lT [3]; a 2-s light and MF exposures to 1.5 Hz and 10 Hz/80 lT [15]; a 16 Hz/28.3 lT MF exposure [19]; an intermittent 16.7-Hz MF exposure [12]; a 2-s 60 Hz/100 lT MF exposure followed by 5-s control [16]; a 90-min MF exposure 50 Hz/ 80 lT [11]; and a 8.3 Hz-12.2 Hz/5 lT sinusoidal MF exposure frequencies corresponding to recorded frontal EEG signals [20]. Other studies have investigated the effects of ELF pulsed electromagnetic fields (PEMF) on EEG activity after the applied Thomas pattern signal D. Cvetkovic (&) Á I. Cosic Science, Engineering and Technology, School of Electrical and Computer Engineering, RMIT University, 376-392 Swanston Street, GPO Box 2476V, Melbourne, VIC 3001, Australia e-mail: dean.cvetkovic@rmit.edu.au (0-500 Hz) pulses in 853-ms segments (18 pulses) at various periods of 110, 220, 330 ms at ±200 lT [4,5,21]; 'during' an ELF PEMF exposure [6].…”