Authors
Preece AW, Iwi G, Davies-Smith A, Wesnes K, et al.

Preece and his colleagues did a study that tested the effect of exposure to RF radiation at cell phone frequency on brain function. They tested two groups of 18 subjects each. The subjects wore a headset-mounted physical model of a phone, which was placed in the normal position with the antenna situated adjacent to the left side of the head. Three conditions were used - the phone was not activated; there was a 915 MHz signal like an analog signal; and there was a 915 MHz signal which simulated a digital signal.

The subjects did 15 different tests of performance. There were four different categories - accuracy on memory tests, speed on memory tests, accuracy on reaction/attention tests, and speed on reaction/attention tests. In both groups the only test affected was the choice reaction time, which involved hitting a "yes" or "no" button as quickly as possible after the corresponding word flashed on a computer screen. The analog test had a mean time of 373.4 mseconds, compared with 384.4 mseconds for digital exposure, and 388.1 mseconds for the controls. There were no significant changes in word, number or picture recall, or in spatial memory.

The results could be due to a chance finding because of multiple testing - the more tests that are analysed, the greater the statistical probability of a spurious finding. However, the results were similar in each of the 2 groups tested, making it less likely that the findings were due to chance.

The authors suggested that the decreased reaction time might be due to an effect on the angular gyrus, which is an area of the brain lying directly beneath the antenna position. This gyrus connects the visual and speech centres. Preece speculated that the effect was due to mild localised heating, which could cause expansion of the blood vessels and improved oxygenation in the area.

The authors point out that their findings are "near, but not at, worst case conditions" - that is, the worst situation that can arise with phone use in respect of power produced.



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