Cook Charles M, Thomas Alex W, Prato Frank S
The Lawson Health Research Institute and Department of Nuclear Medicine and MR, St. Joseph's Health Care (London), London, Ontario, Canada.
Bioelectromagnetics. 2004 Apr;25(3):196-203. doi: 10.1002/bem.10188.
An increasing number of reports have demonstrated a significant effect of extremely low frequency magnetic fields (ELF MFs) on aspects of animal and human behavior. Recent studies suggest that exposure to ELF MFs affects human brain electrical activity as measured by electroencephalography (EEG), specifically within the alpha frequency (8-13 Hz). Here we report that exposure to a pulsed ELF MF with most power at frequencies between 0 and 500 Hz, known to affect aspects of analgesia and standing balance, also affects the human EEG. Twenty subjects (10 males; 10 females) received both a magnetic field (MF) and a sham session in a counterbalanced design for 15 min. Analysis of variance (ANOVA) revealed that alpha activity was significantly higher over the occipital electrodes (O1, Oz, O2) [F(1,16) = 6.858; P =.019, eta2 = 0.30] and marginally higher over the parietal electrodes (P3, Pz, P4) [F(1,16) = 4.251; P =.056, eta2 = 0.21] post MF exposure. This enhancement of alpha activity was transient, as it marginally decreased over occipital [F(1,16) = 4.417; P =.052; eta2 = 0.216] and parietal electrodes [F(1,16) = 4.244; P =.056; eta2 = 0.21] approximately 7 min after MF exposure compared to the sham exposure. Significantly higher occipital alpha activity is consistent with other experiments examining EEG responses to ELF MFs and ELF modulated radiofrequency fields associated with mobile phones. Hence, we suggest that this result may be a nonspecific physiological response to the pulsed MFs.
越来越多的报告表明，极低频磁场（ELF MFs）对动物和人类行为的多个方面具有显著影响。最近的研究表明，暴露于ELF MFs会影响通过脑电图（EEG）测量的人类大脑电活动，特别是在阿尔法频率（8 - 13赫兹）范围内。在此我们报告，暴露于一种脉冲ELF MF（其大部分功率在0至500赫兹之间，已知会影响镇痛和站立平衡等方面）也会影响人类EEG。20名受试者（10名男性；10名女性）按照平衡设计接受了15分钟的磁场（MF）和假刺激实验。方差分析（ANOVA）显示，在枕叶电极（O1、Oz、O2）上方，阿尔法活动显著增强[F(1,16) = 6.858；P =.019，偏 eta 方 = 0.30]，在顶叶电极（P3、Pz、P4）上方略微增强[F(1,16) = 4.251；P =.056，偏 eta 方 = 0.21]，在暴露于MF之后。这种阿尔法活动的增强是短暂的，因为与假刺激暴露相比，在暴露于MF后约7分钟，在枕叶[F(1,16) = 4.417；P =.052；偏 eta 方 = 0.216]和顶叶电极[F(1,16) = 4.244；P =.056；偏 eta 方 = 0.21]上方它略微下降。枕叶阿尔法活动显著更高与其他检查EEG对ELF MFs以及与手机相关的ELF调制射频场反应的实验结果一致。因此，我们认为这个结果可能是对脉冲MF的一种非特异性生理反应。
