What's New - Archives - February 2000

A study conducted with young men at the University of Zurich, which was published in Neuroscience Letters 1999, reported intermittent exposure to 900 MHz radiation reduced the amount of time spent awake during the night after first falling asleep. Changes also occurred in the electroencephalogram recordings of the subjects' brain waves. "More details of the study by Borbely et al can be found in "Research - Clinical -EEG"

In March, 1999, the UK Minister for Public Health asked the National Radiological Protection Board to set up an independent expert group on mobile phones. The terms of reference were: "To consider present concerns about the possible health effects from the use of mobile phones, base stations and transmitters, to conduct a rigorous assessment of existing research and to give advice based on the present state of knowledge. To make recommendations on further work that should be carried out to improve the basis for sound advice."

Collectively, the Expert Group has knowledge in epidemiology and experimental biology related to exposures to electromagnetic fields and radiofrequencies, social sciences, risk perception, and legal issues. In addition to members with lay interests, the Expert Group represents a broad spectrum of medical and scientific interests including oncology, physics, statistics and neurophysiology. The World Health Organisation and the NRPB Advisory Group on Non-ionising Radiation also have representatives amongst the members group.

The group issued a public call for written evidence and has held four public meetings between November and January, with another planned for February. The Expert Group has created a website - www.iegmp.org.uk/index.html

Preece and his colleagues conducted a study that tested the effect of RF radiation exposure at cell phone frequency on brain function. They tested two groups of 18 subjects. 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. During the study 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 participated in 15 different performance tests spanning four 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. Amongst the choice reaction time tests the analog exposure had a mean time of 373.4 mseconds, compared with 384.4 mseconds for digital exposure, and 387.9 mseconds for the controls. There were no significant changes in word, number or picture recall, or spatial memory.

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 resulting effect was due to mild localised heating, which could cause expansion of the blood vessels and improved oxygenation in the area.

Reference: Preece AW, Iwi G, Davies-Smith A, Wesnes K, et al. (1999): Effect of a 915-MHz simulated mobile phone signal on cognitive function in man. Int J Radiat Biol 75:447-456.