QuoteCell phones were placed next to the left and right ears of the volunteers. Scans of the brain were taken with only the right cell phone turned on and with the sound muted for 50 minutes. Brain scans were taken again with both phones turned off.
The results showed that glucose metabolism increased in the area of the brain near the antenna of the phone that was turned on, but not near the one that was turned off. However, the researchers determined that the results were of "unknown clinical significance," meaning they couldn't tell whether the increased brain activity actually entails any health risks.