Scientists from the National Institutes of Health in Maryland, US, found that 50 minutes of mobile phone use was associated with increased 'brain glucose metabolism' - a marker of brain activity - in the region of the brain closest to the phone antenna.
It's the best direct evidence so far that mobile phone use can affect the brain - although the researchers stress that there's no evidence either way of whether the increase in activity has any health effects.
Previous studies of the health effects of mobile phone use have been inconclusive, and have generally looked for associations between phone use and incidence of ill health.
But the new study - published in the Journal of the American Medical Association - looked directly at brain chemistry while phones were in use.
The study saw 47 people having their brains scanned while mobile phones were placed on their left and right ears. Their brain glucose metabolism was measured twice - once with the right-hand phone activated (but the sound muted) for 50 minutes and once with both phones deactivated.
The researchers found that whole-brain metabolism did not differ between the on and off conditions - but there were significant 'regional' effects, with metabolism in the brain region closest to the antenna approximately 7% higher when the mobile phone was on.
The researchers say in their paper: 'Results of this study provide evidence that acute cell phone exposure affects brain metabolic activity. However, these results provide no information as to their relevance regarding potential carcinogenic effects (or lack of such effects) from chronic cell phone use.
'Further studies are needed to assess if these effects could have potential long-term harmful consequences.'
Reacting to the study, Professor Patrick Haggard, of the Institute of Cognitive Neuroscience at University College London, said: 'This is a very interesting result, since it suggests a possible direct effect of mobile phone signals on brain function. However, the result should be treated with some caution.
'It would be useful to know whether participants could tell if the phone was on or off. Simply knowing that the phone is on could influence brain activity, so the results can only definitively be attributed to the mobile phone signals if this can be ruled out.'
He added: 'As the authors point out, the implications for health remain unclear. Much larger fluctuations in brain metabolic rate occur naturally, for example during thinking.'
0 comments:
Post a Comment