Cellphone exposure linked to changes in brain activity

US researchers have shown that less than an hour of cellphone use can significantly speed up activity in the part of the brain closest to the handset antenna, a finding that could reignite the debate over the health effects of radiation emitted by the ubiquitous devices.

In a study published on Wednesday in the Journal of the American Medical Association, and reported by The New York Times, researchers from the National Institutes of Health found that just 50 minutes of cellphone use was accompanied by a seven-per-cent increase in activity in the part of the brain closest to the antenna.

Researchers said the increase was unlikely to be associated with heat from the handset because the activity occurred near the antenna, rather than where the phone touched the head. The scientists also discounted the likelihood of auditory stimulation from the phone. Each of the 47 study participants were subjected to two separate exposures, one with the cellphones turned off and the other with the muted phone receiving a call from a recorded message.

As the subjects touched the phones to their ears, they underwent PET, or positron emission tomography, scans, which measure brain glucose metabolism, a marker of brain activity.

“The study is important because it documents that the human brain is sensitive to the electromagnetic radiation that is emitted by cellphones,” Dr. Nora D. Volkow, director of the National Institute on Drug Abuse, told the NYT. “It also highlights the importance of doing studies to address the question of whether there are – or are not – long-lasting consequences of repeated stimulation, of getting exposed over five, 10 or 15 years.”

The study is among the first and biggest to document that the weak radio frequency signals from handsets have the potential to change brain function. ®