The debate over the health effects of cell phone use was reignited this week with the release of National Institutes of Health (NIH) findings that less than one hour of cell phone use can accelerate activity in the region of the brain closest to the cell phone antenna. Published Wednesday in the Journal of the American Medical Association, the NIH study is one of the largest to date that documents the potential of relatively weak cellular radiofrequency signals to alter brain activity. Though considered significant by the NIH researchers, the study, stressed Dr. Nora Volkow of the National Institute on Drug Abuse, proves merely that cell phone signals have the ability to alter brain activity and does not reach any conclusions about any harmful (or beneficial) health effects from that altered activity. As such, Dr. Volkow told reporters that the study “highlights the importance of doing [further] studies to address the question of whether there are—or are not—long-lasting consequences of repeated stimulation, of getting exposed over five, ten or fifteen years.” In the NIH study, 47 participants were fitted with a cell phone on each ear and were asked to undergo two 50-minute PET scans to assess the effects of radiation emitted from their cell phones on their brains. During the first scan, the cell phones were turned off. However, during the second scan, the phone on the right ear was activated to receive a recorded call but was muted so the subject could not hear. On average, the results of the second PET scan showed a 7% increase in glucose metabolism in the area of the brain closest to the antenna of the activated cell phone. Meanwhile, the results of previous scientific studies on cell phone use cited by American Cancer Society, the National Cancer Institute and the Food and Drug Administration—including a study released last year by the World Health Organization—show no connection between wireless phone use and increased risk of brain tumors among cell phone users. Commenting on the NIH study, John Walls, the vice president of public affairs for wireless association CITA, reiterated that “peer-reviewed scientific evidence has overwhelmingly indicated that wireless devices, within the limits established by the FCC, do not pose a public health risk or cause any adverse health effects.”