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都是手机惹的祸？ Cellphone headaches all in the mind [ 2007-05-28 16:27 ] Exposure tothe radiofrequency fields generated by mobile phones does not cause headpain or increase blood pressure, according to aNorwegian study. Instead, people who experience such symptoms do so because they expectthat they will occur, the findings suggest.Dr Gunnhild Oftedal and associates at the Norway University of Scienceand Technology in Trondheim recruited 17 subjects who "regularlyexperienced pain or discomfort in the head during or shortly after mobilephone calls lasting between 15 and 30 minutes."The participants were tested during mobile phoneradiofrequency exposure and shamexposure, without knowing which session was which. Eachsession lasted 30 minutes, and 65 pairs of trials were conducted.As reported in the medical journal Cephalalgia, the subjects said theyfelt 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 correlationsbetween 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 headachesand discomfort reported by the subjects "is that the symptoms are dueto negative expectations." | 
