都是手机惹的祸？

都是手机惹的祸？
Cellphone headaches all in the mind

Exposure to the radiofrequency fields generated by mobile phones does not cause head pain or increase blood pressure, according to a Norwegian study.

Instead, people who experience such symptoms do so because they expect that they will occur, the findings suggest.

Dr Gunnhild Oftedal and associates at the Norway University of Science and Technology in Trondheim recruited 17 subjects who "regularly experienced pain or discomfort in the head during or shortly after mobile phone calls lasting between 15 and 30 minutes."

The participants were tested during mobile phone radiofrequency exposure and sham exposure, without knowing which session was which. Each session lasted 30 minutes, and 65 pairs of trials were conducted.

As reported in the medical journal Cephalalgia, the subjects said they felt an increase in pain or discomfort during 68 per cent of all trials. The degree of symptoms was not associated with the order of trials.

The researchers observed no statistically significant correlations between actual exposures and the subjects' reports of symptom severity, and no effects of exposure on changes in heart rate or blood pressure.

Oftedal's team concludes that the most likely explanation for the headaches and discomfort reported by the subjects "is that the symptoms are due to negative expectations."
 

挪威一项最新研究表明，置身手机所产生的射频场不会导致头痛或血压升高。

研究结果表明，出现这些症状的人主要是因为他们自己觉得会出问题。

挪威科技大学（位于特隆赫姆）的甘赫尔德·奥弗泰德尔博士和他的同事共招募了17名研究对象，这些人“经常在打15至30分钟电话的过程中或刚打完后出现头痛或头部不适症状”。

研究人员让研究对象在不知情的情况下，分别置于射频场及假性辐射中。每一环节持续30分钟，共进行了65组试验。

在医学杂志Cephalalgia上发表的研究报告表明，在68%的试验中，研究对象称感到头痛或不适症状加重。而症状的轻重程度与试验的顺序没有关系。

研究人员并没有发现置身射频场与所述症状的严重程度之间存在明显的数据上的相关，也没有发现射频场对心率与血压的变化有影响。

奥弗泰德尔博士的研究小组得出结论，对于研究对象头痛和不适症状最合理的解释应该是“消极的预期。”

sham :not genuine;something fault or empty（假的；赝品）