Crasson M, Legros J J, Scarpa P, Legros W
Belgian BioElectroMagnetic Group, Psychoneuroendocrinology Unit, University of Liege, Belgium.
Bioelectromagnetics. 1999 Dec;20(8):474-86. doi: 10.1002/(sici)1521-186x(199912)20:8<474::aid-bem2>3.0.co;2-m.
Two double-blind studies were performed to examine magnetic field (MF) exposure effects and to determine the impact of temporal variation (continuous vs. intermittent exposure) of 100 mu T(rms) 50 Hz MF diurnal exposure on psychological and psychophysiological parameters in healthy humans. Three cephalic exposure sessions of 30-min, i.e., sham, continuous, and intermittent (15 s ON/OFF cycles) MF conditions, were involved. Each subject participated in all sessions, which were spaced at 1-wk intervals. In each session, mood ratings and performance measures were obtained before, during, or after exposure and several electrophysiological data (event-related brain potentials [ERP]) were recorded after each exposure session. These criteria were chosen to evaluate sensory functions as well as automatic and voluntary attentional processes. In experiment 1, 21 healthy male volunteers (20 to 27 years of age) were studied. Ten subjects were exposed at 13:30 h, and 11 subjects were exposed at 16:30 h. Statistically significant changes in the amplitude of ERP were observed after MF exposure in the dichotic listening task, indexing selective attention processes. Eighteen of the 21 original male volunteers took part in experiment 2, undertaken to better understand the results related to information processing involved in selective attention and control for ultradian rhythmicity. Exposure time for all the subjects was at 13:30 h. The analysis of the data again revealed significant amplitude changes of the ERP recorded in the dichotic listening task. Moreover, they demonstrated ERP latency and reaction time slowing in the oddball paradigm, a visual discrimination task after real MF exposure. These results also indicate that a low level 50 Hz MF may have a slight influence on event-related potentials and reaction time under specific circumstances of sustained attention.
进行了两项双盲研究，以检查磁场（MF）暴露的影响，并确定100μT（均方根值）50Hz MF日间暴露的时间变化（连续暴露与间歇暴露）对健康人类心理和心理生理参数的影响。研究涉及三个30分钟的头部暴露时段，即假暴露、连续MF暴露和间歇MF暴露（15秒开/关周期）。每个受试者都参与了所有时段的研究，各时段间隔为1周。在每个时段中，在暴露前、暴露期间或暴露后获取情绪评分和表现测量数据，并在每次暴露时段后记录若干电生理数据（事件相关脑电位[ERP]）。选择这些标准来评估感觉功能以及自动和自主注意力过程。在实验1中，研究了21名健康男性志愿者（20至27岁）。10名受试者在13:30暴露，11名受试者在16:30暴露。在双耳分听任务中，MF暴露后观察到ERP振幅有统计学意义的变化，这表明了选择性注意过程。21名原始男性志愿者中的18人参与了实验2，该实验旨在更好地理解与选择性注意中信息处理相关的结果以及对超日节律的控制。所有受试者的暴露时间均为13:30。对数据的分析再次显示，在双耳分听任务中记录的ERP有显著的振幅变化。此外，他们还证明了在真实MF暴露后的视觉辨别任务——奇偶数范式中，ERP潜伏期和反应时间延长。这些结果还表明，在持续注意的特定情况下，低水平50Hz MF可能对事件相关电位和反应时间有轻微影响。
