Graham C, Cook M R, Cohen H D, Gerkovich M M
Midwest Research Institute, Kansas City, Missouri 64110.
Bioelectromagnetics. 1994;15(5):447-63. doi: 10.1002/bem.2250150508.
This human exposure study examined the relationship between field strength and biological response and tested whether the exposure levels at which the greatest effects occur differ for different endpoints. Three matched groups of 18 men each participated in two 6 h exposure test sessions. All subjects were sham exposed in one session. In the other session, each group of subjects was exposed at a different level of combined electric and magnetic field strength (low group:6 kV/m, 10 microT; medium group:9 kV/m, 20 microT; and high group: 12 kV/m, 30 microT). The study was performed double blind, with exposure order counterbalanced. Significant slowing of heart rate, as well as alternations in the latency and amplitude of event-related brain potential measures derived from the electro encephalogram (EEG), occurred in the group exposed to the 9 kV/m, 20 microT combined field (medium group). Exposure at the other field strength levels had no influence on cardiac measures and differential effects on EEG activity. Significant decrements in reaction time and in performance accuracy on a time estimation task were observed only in the low group. These results provide support for the hypothesis that humans may be more responsive to some combinations or levels of field strength than to others and that such differences in responsivity may depend, in part, on the endpoint of interest.
这项人体暴露研究考察了场强与生物反应之间的关系，并测试了不同终点指标下产生最大效应的暴露水平是否存在差异。三组各18名匹配的男性参与了两个6小时的暴露测试环节。所有受试者在其中一个环节接受假暴露。在另一个环节，每组受试者在不同的电场和磁场强度组合水平下接受暴露（低强度组：6 kV/m，10微特斯拉；中等强度组：9 kV/m，20微特斯拉；高强度组：12 kV/m，30微特斯拉）。该研究采用双盲方式进行，暴露顺序相互平衡。在暴露于9 kV/m、20微特斯拉组合场的组（中等强度组）中，出现了心率显著减慢以及脑电图（EEG）得出的事件相关脑电位测量的潜伏期和振幅的变化。在其他场强水平下的暴露对心脏指标没有影响，对EEG活动有不同影响。仅在低强度组中观察到时间估计任务的反应时间和表现准确性显著下降。这些结果支持了以下假设：人类可能对某些场强组合或水平比其他组合或水平更敏感，并且这种反应性差异可能部分取决于所关注的终点指标。
