Preece A W, Iwi G, Davies-Smith A, Wesnes K, Butler S, Lim E, Varey A
Bristol Oncology Centre, University of Bristol, UK.
Int J Radiat Biol. 1999 Apr;75(4):447-56. doi: 10.1080/095530099140375.
To examine whether a simulated mobile telephone transmission at 915 MHz has an effect on cognitive function in man.
Thirty-six subjects in two groups were each given two training sessions and then three test sessions in a randomized three-way cross-over design. About 1 W mean power at 915 MHz from a quarter-wave antenna mounted on a physical copy of an analogue phone, as a sine wave, or modulated at 217 Hz with 12.5% duty cycle, or no power, was applied to the left squamous temple region of the subjects while they undertook a series of cognitive function tests lasting approximately 25-30 min. The second group was investigated for sleep, consumption of alcohol and beverages, and any other substances that might affect performance.
In both groups, the only test affected was the choice reaction time and this showed as an increase in speed (a decrease in reaction time). There were no changes in word, number or picture recall, or in spatial memory. While an effect of visit-order was evident suggesting a learning effect of repeat tests, the design of the study allowed for this. Additionally, there was no systematic error introduced as a result of consumption of substances or sleep time.
There was evidence of an increase in responsiveness, strongly in the analogue and less in the digital simulation, in choice reaction time. This could be associated with an effect on the angular gyrus that acts as an interface between the visual and speech centres and which lies directly under and on the same side as the antenna. Such an effect could be consistent with mild localized heating, or possibly a non-thermal response, which is nevertheless power-dependent.
研究915MHz模拟移动电话传输是否对人类认知功能有影响。
36名受试者分为两组，采用随机三向交叉设计，每组均接受两次训练课程，然后进行三次测试课程。在受试者进行一系列持续约25 - 30分钟的认知功能测试时，将安装在模拟手机实体模型上的四分之一波长天线以正弦波形式、或在217Hz频率下以12.5%占空比调制、或无功率输出的方式，向受试者左侧颞部施加约1W的915MHz平均功率。对第二组受试者的睡眠、酒精和饮料摄入量以及任何可能影响测试表现的其他物质进行了调查。
在两组中，唯一受影响的测试是选择反应时间，表现为速度增加（反应时间减少）。单词、数字或图片回忆以及空间记忆均无变化。虽然访视顺序的影响明显，表明重复测试存在学习效应，但研究设计已考虑到这一点。此外，物质摄入或睡眠时间并未导致系统性误差。
有证据表明，在选择反应时间方面，反应性有所增加，在模拟信号中表现强烈，在数字模拟中则较弱。这可能与对视角回的影响有关，视角回是视觉和言语中枢之间的接口，直接位于天线下方且与天线同侧。这种影响可能与轻度局部加热一致，或者可能是一种与功率相关的非热反应。
