Auteurs
Eltiti S, Wallace D, Ridgewell A, Zougkou K, et al. (2007a)

This study was designed to assess the effect of exposure to base station signals on individuals with electrical hypersensitivity or on controls. Fifty-six self-reported sensitive and 120 controls completed an open provocation test, in which the participants and the examiners knew when the "base station" signal was "on" or "off". The subjects were exposed to a GSM signal, a UTMS signal, and a sham signal, each for 15 minutes. The GSM signal was at combined 900 and 1800 MHz frequencies, and a power flux density of 10 mW/m². The UTMS was at 2,020 MHz frequency, at the same power flux density. In this session subjective wellbeing was measured using a visual analogue scale (VAS), and a quick double-blind test to assess whether participants could judge whether the signal was "on" or "off" during further 5-minute exposures. In the next 3 sessions, held at least 1 week apart, the subjects were exposed to either the GSM, the UMTS, or a sham signal, and the testing was double-blind. The exposure was for a total of 48 minutes. In the first 20 minutes the subjects watched a video, completed VAS every 5 minutes, and had physiological measures taken. These measures were blood volume pulse (BVP), skin conductance (SC), and heart rate (HR). In the next 20 minutes, the subjects performed mental arithmetic, and VAS measures were completed every 5 minutes. Cognitive tests (to be reported on later) were done in the last 8 minutes. "On" or "off" judgments were made as in the first session. The sessions 2-4 were designed to be counterbalanced, but since the number of participants was less than anticipated, the counterbalancing was not totally effective, and almost half the sensitive subjects received the UTMS exposure first.

During the open provocation, sensitive individuals reported lower levels of wellbeing in both the UTMS and UTMS exposures than in the sham, while controls reported more symptoms in the UTMS signal. During double-blind tests the GSM signal did not have any effect on either group. Sensitive individuals reported increased levels of arousal during the UTMS signal, but further analysis indicated that the difference was likely to be due to the effect of order of exposure rather than the exposure itself. Physiological measures did not differ across the three exposure conditions for either group. Neither group was able to accurately assess whether the signal was "on" or "off".

Sensitive individuals reported more symptoms and greater severity of symptoms and also displayed higher levels of skin conductance than control individuals regardless of the type of exposure. The authors suggest that these findings could reflect either a psychophysiological stress or a more general imbalance in autonomic nervous system regulation.


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