EEG electrode caps can reduce SAR induced in the head by GSM900 mobile phones.

This paper investigates the influence of EEG electrode caps on specific absorption rate (SAR) in the head from a GSM900 mobile phone (217-Hz modulation, peak power output 2 W). SAR measurements were recorded in an anthropomorphic phantom using a precision robotic system. Peak 10 g average SAR in the whole head and in just the temporal region was compared for three phantom arrangements; no cap, 64-electrode "Electro-Cap," and 64-electrode "Quick-Cap". Relative to the "no cap" arrangement, the Electro-Cap and Quick-Cap caused a peak SAR (10 g) reduction of 14% and 18% respectively in both the whole head and in the temporal region. Additional computational modeling confirmed that SAR (10 g) is reduced by the presence of electrode leads and that the extent of the effect varies according to the orientation of the leads with respect to the radiofrequency (RF) source. The modeling also indicated that the nonconductive shell between the electrodes and simulated head material does not significantly alter the electrode lead shielding effect. The observed SAR reductions are not likely to be sufficiently large to have accounted for null EEG findings in the past but should nonetheless be noted in studies aiming to measure and report human brain activity under similar exposure conditions.

Examining the effects of electromagnetic fields emitted by GSM mobile phones on human event-related potentials and performance during an auditory task.

OBJECTIVE: Due to the widespread use of mobile phones (MP), it is important to determine whether they affect human physiology. The aim of this study was to explore the sensitivity of auditory event-related potentials to electromagnetic emissions. METHODS: Twelve participants attended two sessions, 1 week apart. Participants performed an auditory oddball task while they were exposed to an active MP during one session and sham exposure during the other. Each condition lasted 1 h and order was counterbalanced. N100 and P200 latencies and amplitudes were analysed for non-target waveforms, and N200 and P300 latencies and amplitudes were analysed for target waveforms. RESULTS: In real relative to sham exposure N100 amplitude and latency to non-targets were reduced, with the reduction larger over midline and right hemisphere sites. P300 latency to targets was delayed in the real exposure condition, however as this difference was greatest at left frontal and left central sites the interpretation of this result is unclear. Reaction time increased in the real relative to sham condition. No difference in accuracy was found. CONCLUSIONS: The results suggest that MP exposure may affect neural activity, particularly in proximity to the phone, however caution should be applied due to the small sample size.