To study whether electromagnetic field emitted by digital cellular phone affects the brain, subjects were exposed during an entire night-sleep episode to an intermittent schedule consisting of alternating 15 minutes "on" and 15 minutes "off" intervals.
Modulation type: pulsed
Exposure duration: intermittent, 15 min on/off, for 8 h
|Exposure duration||intermittent, 15 min on/off, for 8 h|
|Duty cycle||87.5 %|
|Repetition frequency||217 Hz|
The pseudo GSM test signal was modulated with frequencies used by handsets and base stations having components of 2, 8, 217, 1736 Hz.
|Distance between exposed object and exposure source||30 cm|
|Chamber||Two sound insulated and temperature controlled bedrooms with absorber walls placed around the bed to approximate an anechoic room and ensure a relatively uniform exposure.|
|Setup||There was an array of three λ/2 dipole antennas behind each bed at a distance of 30 cm from the head of the recumbent subject. The polarization of the field was perpendicular to the surface of the bed.|
|Additional info||The experiment consisted of two sessions one week apart. EMF or sham exposure was given according to a randomized, placebo controlled, double-blind study, cross-over study design. During an adaptation night per session in a different room, the absorber walls were mimicked by fabric.|
|SAR||1 W/kg||maximum||measured||10 g||-|
Compared with a control night the amount of waking after sleep onset was reduced from 18 to 12 min. Spectral power of the EEG in non-rapid eye movement sleep (REM sleep) was increased. The maximum rise occured in the 10.0-11.0 Hz and 13.5-14.0 Hz bands during the initial part of sleep and then subsided. The data demonstrate that pulsed high-frequency electromagnetic field in the range of cellular phones may promote sleep and modify sleep EEG.