It's always wise to admit one's biases, so I'll be honest about mine: I despise cell phones. I can't enjoy a meal in a restaurant without intermittent blasts of a "We Will Rock You" ringtone from the next table. I can't savor a peaceful stroll in the park; everyone I pass is rattling into a cell phone and scaring the birds away. A trip down the aisles of the supermarket makes me privy to the embarrassing details of personal relationships that are frankly none of my business. On a more serious note, I can't count how many times I've been nearly rear-ended or sideswiped by a cell-phone chattering driver. Luckily, one of us was paying attention to the road.

Given my biases, my selection of research for my Brain Sense blog this week should come as no surprise. Researchers at the National Institutes of Health report in the Journal of the American Medical Association on the effects of cell phone radiation on brain activity. The research is a methodologically rock-solid and fairly ambitious look into a question that has troubled physicians and cell phone users for some time: Is the electromagnetic field of the cell phone signal affecting neurons in the brain? There is reason to suspect that it might. The field isn't strong, but some of the frequencies are dangerously close to the ones the brain itself uses. Furthermore, we know that most of the radiofrequency energy from a cell phone is absorbed by the head and hand of the user. For various reasons, the heat released by the cell phone is probably not a concern, but the possible effects of the phone's radiation on brain activity, development, and human behavior certainly are.

This new study should heighten those concerns. The research team placed cell phones on the left and right ears of 47 healthy volunteers whose brain metabolism was then measured using positron emission tomography (PET). The investigators scanned their subjects' brain twice: once with the right-ear cell phone on (but with the sound muted); and again with both phones off. The scans, which lasted for 50 minutes in both trials, clearly showed two changes in the brain:
• The radiofrequency radiation emitted from the "on" cell phone increased glucose metabolism in the region of the cerebral cortex closest to the phone antenna.
• The predicted rate of radiofrequency absorption in a brain region accurately predicted the amount of increased glucose metabolism.

Glucose metabolism, phone-on (left) and phone-off (right). Copyright 2011 AMA. All rights reserved.

Overall, the researchers found that whole-brain metabolism did not differ between the phone-on and phone-off conditions. However, regional differences were significant. Metabolism in the brain region closest to the antenna (orbitofrontal cortex and temporal pole) was significantly higher (approximately 7 percent) for the phone-on condition compared to the phone-off. "The increases were significantly correlated with the estimated electromagnetic field amplitudes . . . ," writes the research team, which was led by Nora D. Volkow, M.D., of the National Institute of Drug Abuse. "This indicates that the regions expected to have the greater absorption of [electromagnetic radiation] from the cell phone exposure were the ones that showed the larger increases in glucose metabolism."

Although no one has yet demonstrated that this alteration in metabolism has any negative, long-term effect on brain health, I'm hoping this research will spark second thoughts among at least a few cell-phone addicts who habitually crank up their ringie-dingies every time they sit, stand, walk, start a car, or purchase a can of soup. I suspect many who learn about this research will continue to use their cell phones with abandon. It's the "can't happen to me" syndrome. Others may just decide that an extra hour a day of mindless jabber isn't worth the risk, so they'll toss their cell phones in their sock drawers.

I'm a big fan of the sock drawer option.

For More Information:

Nora D. Volkow et al. "Effects of Cell Phone Radiofrequency Signal Exposure on Brain Glucose Metabolism," JAMA (Feb. 23, 2011) 305(8): 808-813.

Henry Lai and Lennart Hardell. "Cell Phone Radiofrequency Radiation Exposure and Brain Glucose Metabolism" (editorial). JAMA (Feb. 23, 2011): 305(8): 828-829.

PET scan used with permission: AMA. Copyright 2011. All rights reserved.

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