Cell Phones Affect Brain, but Does It Matter?
Study Shows Rise in Glucose Metabolism in Brain; Long-Term Effect Is Unlcear
By Kathleen Doheny
WebMD Health News
Reviewed by Laura J. Martin, MD

Feb. 22, 2011 -- Cell phone use appears to have an effect on brain activity, boosting the metabolism of brain glucose in specific areas, according to a new study.

Whether it's something to be concerned about or not remains to be seen. "We don't know that this is harmful," researcher Nora Volkow, MD, director of the National Institutes of Health's National Institute on Drug Abuse, tells WebMD.

What is known, she says, is that "glucose metabolism is a direct indicator of brain activity." Brain cells use the sugar for energy.

In her study, she found those who used a cell phone for 50 minutes had about a 7% rise in glucose metabolism in the brain region closest to the antenna, as documented on PET (positron emission tomography) scans.

So far, Volkow says, her new research shows that "the human brain is sensitive to the electromagnetic radiation that is delivered by cell phones." Beyond that, more research is needed, she says.

The study is published in the Journal of the American Medical Association.
Measuring Brain Metabolism

Volkow and colleagues placed cell phones on the left and right ears of 47 healthy volunteers and then performed the PET scans. They measured the metabolism of glucose in the brain twice, once with the right cell phone activated but the sound muted for 50 minutes (the ''on'' condition) and once with both cell phones deactivated (the "off" condition).

When they looked at overall brain metabolism and compared PET scans, they did not find a difference between the "on" and "off'' conditions. But they did find regional effects -- the 7% boost in the area closest to the antenna when the phone was on.

That area includes the orbitofrontal cortex and temporal pole, involved with such functions as memory and other cognitive skills.

That amount of increase in glucose metabolism, Volkow says, is within the range of increase seen when someone does a cognitive task, such as moving their finger. "It's not a dramatic effect," she tells WebMD. Yet the differences are clear, she says.

The study is believed to be the first to look at brain metabolism in response to cell phone exposure. The next question, Volkow says, is whether there are long-term effects.
Cell Phones and Brain: More Questions

''It's a very interesting finding, the implication of which is unclear," agrees Keith Black, MD, chair and professor of neurosurgery at Cedars-Sinai Medical Center in Los Angeles, who also directs its Maxine Dunitz Neurosurgical Institute and holds the Ruth and Lawrence Harvey Chair in Neuroscience.

He reviewed the findings for WebMD but was not involved in the study.

"Whether [the increased metabolism] could have a long-term effect on memory, on language, is unclear, but it certainly raises those areas as something we need to try to understand," Black says.