February 23, 2011
Study Finds Cellphone Use Alters Brain Activity
Speaking directly into a cellphone while holding it against your ear can alter brain activity in those areas closest to the device's antenna, claims a new study published Tuesday in the Journal of the American Medical Association (JAMA).
Researchers at the National Institutes of Health (NIH) and the Brookhaven National Laboratory in New York studied 47 adults over the course of a year, using positron emission tomography (PET) to measure their glucose metabolism, or the amount of sugar it takes a cell to fuel activity, according to Shirley S. Wang of the Wall Street Journal.
"They conducted scans after subjects had cellphones held to their left and right sides for 50 minutes on two different days," she said. "The first day neither cellphone was turned on. The second day the right phone was activated but muted so the participants wouldn't hear any noise. Because the participants didn't know which phone was active, their expectations couldn't skew the results."
They discovered that areas of the brain that were closest to the antenna became "significantly more active" when an operational cellphone was held next to the ear, even when it wasn't used to conduct a conversation, according to Wang.
In fact, their glucose metabolism levels spiked an average of 8% to 10%, which is said to be comparable to the increase in metabolism in the visual cortex when speaking to someone, study author Dr. Nora Volkow told the Wall Street Journal.
What remains unclear is whether or not that alteration of brain activity can cause harm to the orbitofrontal cortex, which is the region affected by the cellphone activity.
In an interview with USA Today's Mary Brophy Marcus, Murali Doraiswamy, the head of biological psychiatry at Duke Medical Center, said that the orbitofrontal cortex is "broadly associated with emotion, sense of smell, memory, eating, aggression--a whole range of behaviors. It's like an orchestra conductor instead of just an individual musician with specific task."
Doraiswamy was not involved in the study.
Neither was Keith Black, chairman of neurosurgery at Cedars-Sinai Medical Center in Los Angeles, who told Marcus, "This study raises a lot of questions"¦ Will cellphones impact how we remember things, is there any relation to the risk of Alzheimer's? Will it affect our cognitive ability to manipulate language functions?"
Black told Marcus that cellphone users should uses a headset, and that texting probably would not have any adverse effects either. Doraiswamy noted that he "always" used speaker phone and never placed the device close to his head, and Volkow herself told Julie Steenhuysen of Reuters that the results of the study have prompted her to begin using an earpiece as well.
"I don't say there is any risk, but in case there is, why not?" the NIH researcher added.
Earlier this month, a University of Manchester study reported that radio frequency exposure from cellphone use did not appear to significantly increase the risk of developing brain cancer.
"Our research suggests that the increased and widespread use of cellphones, which in some studies was associated to increased brain cancer risk, has not led to a noticeable increase in the incidence of brain cancer in England between 1998 and 2007," lead researcher Dr. Frank de Vocht, an occupational and environmental health expert at the university, said in a statement.
"It is very unlikely that we are at the forefront of a brain cancer epidemic related to cellphones, as some have suggested, although we did observe a small increased rate of brain cancers in the temporal lobe corresponding to the time period when cellphone use rose from zero to 65% of households," he added.
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