Mobile phone users show slowed brain activity

1 October 2007

Nijmegen, The Netherlands. Frequent mobile phone use slows brain function, according to a recent study published in the International Journal of Neuroscience.

The study also found, however, that frequent mobile phone users showed better focused attention, which can be explained as a learning effect related to making more phone calls in distractive surroundings.

No firm conclusions can be drawn as to whether these effects are to be considered an adverse health effect or not, but data have already been collected from more than 20,000 people to replicate this study and further investigate the adverse health effects.

This study was carried out by researchers from Brainclinics Diagnostics and the Radboud University department of Biological Psychology both from Nijmegen, the Netherlands, the Institute of Psychiatry, London and the Brain Resource Company Ltd, Sydney.

Earlier studies have mostly investigated the acute effects of mobile phone use on brain function. However, this study employed an epidemiological approach to investigate the long-term effects of mobile phone use on brain function.

In this study, data was used from 300 people of which 100 were 'frequent mobile phone users', 100 'non-mobile phone users' and an 'intermediate group' of 100 people. Differences in brain activity (measured using quantative EEG), neuropsychological functions such as attention, memory and executive function and personality traits were assessed.

The results show that frequent mobile phone users score higher on extraversion — thought to be more likely a cause rather then an effect — and also showed improved focused attention. This was explained by a learning effect due to making more phone calls in busy environments, whereby people learn to focus better on the phone call and filter out irrelevant environmental information.

However, the brain activity from frequent mobile phone users shows more slow activity (increased Delta and Theta) and a slowing of the Alpha Peak Frequency interpreted as a general slowing of brain activity.

These effects could not be explained by the differences in personality and focused attention. "In Alzheimer's dementia you also find a severely slowing of brain activity. However, the slowing found in this study, with mobile phone users, can still be considered within 'normal' limits," said Martijn Arns, the main investigator. "The frequent mobile phone user group used their mobile phone — at the time of data collection — only 2.4 years on average, which can currently be considered as a short time. Therefore, it is to be further investigated whether the observed effects in this study are more severe with prolonged mobile phone use."

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