ID Number		1136
Study Type		Human / Provocation
Model		20 Hz to 18 kHz (PW) exposure to human volunteers and analysis of EEG, motor control, and other functional endpoints
Details		Human volunteers (n=20) were exposed to pulsed ELF (18 pulses within 853 milliseconds at 20 Hz to 18 kHz). Each pulse was a "doublet" going twice from 0 to + 200 microTesla to - 200 microTesla and back to 0, with a maximum rise time of 1 millisecond, resulting in a maximum field change of 0.4 microT/sec. The packets of pulses were separated by varying refractory periods (no magnetic field) of 110, 220, 330, and 1200 msec, repeated throughout a 15 minute exposure period. The authors measured EEG immediately following exposure using a vertical Helmholtz coil ~ 2 meters in size driven by a constant current amplifier via a digital to analog converter. Subjects were seated within the exposure area and a 12 electrode EEG recording was taken via a QuikCap apparatus. Vertical electrooculogram measurements were also taken to control for eye-movement effects. EEG was evaluated over theta (4-7 Hz), alpha (8-13 Hz), beta (14-35 Hz), and gamma (35-80 Hz) bands. The authors report both ELF and sham exposure resulted in large decreases in alpha activity at both the occipital and parietal electrodes (as compared to pre-exposure recordings). The decrease was significantly less (i.e. the alpha activity was higher) 1 minute after the MF exposure compared to the sham, indicating an exposure effect (particularly at the occipital electrodes but also at the parietal electrodes). In contrast, a significantly lower amount of alpha activity was noted after the MF exposure vs. sham exposure at the frontal electrodes, but only in data from the last minute of the sampling period. No differences were found in the theta, beta, or gamma bands at any electrode. The authors conclude "pulsed ELF has an effect on the resting human EEG". Further, since alpha activity is associated with periods of "relaxed wakefulness" and possibly connected to memory performance, the result supports previous literature suggesting increased occipital alpha activity after ELF MFs and ELF-modulated RF fields, such as those from mobile phones. Ongoing studies include exposing volunteers (n = 70) to 1800 microT ELF magnetic field during testing of resting EEG, physiologic tremor, voluntary hand movement, standing balance, local blood perfusion, systolic blood pressure, skin temperature, and ECG. Preliminary results show no effect on occipital EEG, postural tremor, and postural oscillations.
Findings		Effects
Status		Completed With Publication
Principal Investigator		University of Western Ontario, Canada
Funding Agency		Hydro Quebec, Canada, CIHR, Ontario Research Fund
Country		CANADA
References		Cook , CM et al. Bioelectromagnetics, (2004) 25:196-203
Comments		The authors found a higher (than sham) alpha at the occipital electrode, but in fact the level was decreased from cage control, only not as decreased as the sham level. Further, in the frontal electrodes, alpha activity following MF exposure was lower than sham in data from the last minute of the sampling period. This seems inconsistent. Further, if alpha activity is associated with memory performance, how is a decrease in overall alpha linked with increases in memory performance (Preece et al). The authors do report that noise, heating, and odor were eliminated as possible indicators of the magnetic field on/off status.