Hamblin Denise L, Anderson Vitas, McIntosh Robert L, McKenzie Ray J, Wood Andrew W, Iskra Steve, Croft Rodney J
Brain Sciences Institute, Swinburne University of Technology, 400 Burwood Rd., Hawthorn, VIC 3122, Australia.
IEEE Trans Biomed Eng. 2007 May;54(5):914-20. doi: 10.1109/TBME.2007.893486.
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.
本文研究了脑电图（EEG）电极帽对GSM900移动电话（217赫兹调制，峰值功率输出2瓦）在头部产生的比吸收率（SAR）的影响。使用精密机器人系统在人体模型中记录了SAR测量值。比较了三种模型布置（无帽、64电极“Electro-Cap”和64电极“Quick-Cap”）在整个头部和仅颞部区域的10克平均峰值SAR。相对于“无帽”布置，Electro-Cap和Quick-Cap在整个头部和颞部区域分别使峰值SAR（10克）降低了14%和18%。额外的计算建模证实，电极引线的存在会降低SAR（10克），并且影响程度会根据引线相对于射频（RF）源的方向而变化。该建模还表明，电极与模拟头部材料之间的非导电外壳不会显著改变电极引线的屏蔽效果。观察到的SAR降低幅度可能不足以解释过去脑电图研究中的阴性结果，但在旨在测量和报告类似暴露条件下人类大脑活动的研究中仍应予以注意。
