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Cell phones may affect brain metabolismActivity rises near phones pressed to ears, study finds

By Laura SandersWeb edition : Tuesday, February 22nd, 2011

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CELLULAR ACTIVITYAfter a 50-minute call to a cell phone on a subject's right side (leftimage), nearby brain regions showed heightened activity (arrow). In a brain with phones placed

to both sides of the head but turned off (right), activity was normal.JAMA, Feb. 23, 2011, Vol.305, p. 808 2011 American Medical Assn.

Power-talkers with cell phones glued to their ears may be getting more than conversation. A 50-

minute call boosts activity in brain regions near the ear where a phone is located, a brain-scanning study published February 22 in the Journal of the American Medical Association

shows.

This is the first paper that really shows there are changes in the brain, says bioengineer Henry

Lai of the University of Washington in Seattle, who coauthored an editorial published in thesame issue ofJAMA. Talking on a cell phone pressed to the ear, he says, is not really safe.

In the study, researchers measured the brain activity of 47 participants who had pairs of Samsung

cell phones strapped to their heads, one on each side. The phone on the left ear was turned off,while the one on the right received a 50-minute recorded message. This phone was kept muted so

that the subject didnt know which phone was on, and also to prevent stimulation of the brainshearing center.

A few minutes after the call, a PET scan revealed that brain regions next to the working phone

had higher levels of glucose metabolism. The left side of the brain and other areas, even thosequite close to the phone, showed no changes. Since active brain cells require glucose, the

increase suggests that cell phone radiation is boosting brain activity. The human brain issensitive to the electromagnetic radiation that is emitted from cell phones, says study coauthor

Nora Volkow of the National Institute on Drug Abuse in Bethesda, Md.

The particular brain regions affected would probably change depending on a phones design and

how a person held it, Volkow says. On the phones used in the study the antennas are near thebottom, so the brain areas involved were the orbitofrontal region, which sits right behind the

eyes, and the temporal pole below it.

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Glucose metabolism rose in these areas by about 7 percent an increase typically seen whenbrain regions become active. For instance, glucose metabolism in the language centers of the

brain rises by about 10 percent when a person is talking, Volkow says.

The increase in brain metabolism observed in the experiment may be an underestimate, because

cell phones emit more radiation when a person is talking, Lai says. Radiation levels also changedepending on the phone type, the distance to the nearest cell phone tower and the number ofpeople using phones in the same area. These variables have prevented scientists from getting

good epidemiological evidence about potential health risks of cell phone usage.

Researchers dont yet know whether cell phone radiation is dangerous. At this point we do notknow what the clinical significance of this particular finding is, Volkow says. The heightened

activity may not have any ill effects, or it may be dangerous, particularly with years of heavy cellphone use or in the developing brains of children and teens.

In my case, I dont like my brain to be stimulated by anything that is not physiological,

Volkow says. There are very easy solutions that dont cost anything for those who want to playit safe. For instance, people can limit their time on the phone, use the speakerphone option, ortalk with a hands-free device thats connected to the phone with a wire.