The electromagnetic radiation emitted by a cellular phone's antenna appears to activate nearby regions of the brain to unusually high levels, said a study published Tuesday in the Journal of the American Medical Association that is likely to spark new concerns about the health effects of wireless devices.
The preliminary study, led by a respected neuroscientist at the National Institutes of Health, raises many more questions than it answers. But by providing solid evidence that cell-phone use has measureable effects on brain activity, it suggests that the nation's passionate attachment to its 300 million mobile phones may be altering the way we think and behave in subtle ways.
Researchers peered inside the brains of 47 healthy subjects using positron emission tomography, also known as PET scanning, to measure the location and timing of brain activity by detecting signs that cells are consuming energy. They found that despite official skepticism that cell phones' electromagnetic energy exerts any influence on nearby cells -- including statements issued by the Food and Drug Administration -- it clearly does.
What the study by Dr. Nora Volkow, director of the National Institute on Drug Abuse, does not suggest is that cell-phone use contributes to the development of brain cancers. A growing body of research has failed to find evidence to support that claim.
The study found that two areas of the brain close to the phone's antenna showed unusual spikes in activity throughout a 50-minute period of live transmission. That the activity occurred closest to the antenna, and not near the place where the phone was in direct contact with the head, signaled to the authors that the changes were a response to electromagnetic signals and not a reaction to the heat generated by the device.
"It's a surprising finding," said Dr. Keith Black, chairman of neurosurgery at Cedars-Sinai Medical Center, who wasn't involved in the study. He said further research is needed to know whether "this is a good effect, a neutral effect or a bad effect."
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