After Brain Study, New Questions About Mobile Phones

I'm Carolyn Presutti with the VOA Special English Health Report, from voaspecialengli... | / voalearningenglish
How important is your mobile phone, better known to Americans as a cellphone? Many people say they use the device all the time. So far, no studies have proven beyond question that the radio signals from cellphones cause brain cancer or other health problems. But a new study by government scientists in the United States has some people wondering what to think. The scientists found that holding a cellphone to your ear for at least fifty minutes increases brain cell activity. Even the scientists themselves are not sure about the meaning of their findings.Dr. Nora Volkow led the study. She heads the National Institute on Drug Abuse, part of the National Institutes of Health. Dr. Volkow says she would not be concerned that fifty minutes of cellphone exposure would harm anyone. But she says the research does show the need to study whether there are long-lasting effects of repeated exposure over several years.Her team studied forty-seven healthy volunteers in two thousand nine. The volunteers had cellphones placed against both ears while the scientists made images of their brain activity. As part of the test, one phone was activated but muted for fifty minutes. The other phone was off. After that, the people were tested with both phones turned off. Dr. Volkow says the brain scans showed increased activity in brain cells closest to the activated phone.She said the right area of the brain that was very close to the antenna showed the largest increase in metabolism compared to when the telephones were off. Even though the radio frequencies emitted from current cellphones are very weak, they are able to activate the human brain.The scans showed how the brain cells used sugar to produce energy, a normal activity. The activity was seven percent higher in areas of the brain closest to the cellphone antenna. Experts say people who are concerned about mobile phones can take steps like using a wired headset.Dr. Giuseppe Esposito is a nuclear medicine expert at Georgetown University Medical Center in Washington. He says after many years of studies, better kinds of research are still needed to settle questions about cellphone safety. These studies would take years. He said there should be epidemiological studies of a population of high users or light users of cellphones and then see what happens over the years.For VOA Special English, I'm Carolyn Presutti.
(Adapted from a radio program broadcast 02Mar2011)