BETHESDA, MARYLAND (BNO NEWS) -- The National Institutes of Health and Brookhaven National Laboratory on Wednesday said their research projects revealed that the use of cell phones for 50 minutes effect brain activity, although its significance is still unclear.

According to the study, the area of the brain closest to the cell phone's antenna elevated its glucose metabolism - which is a form of measuring brain cell activity - due to the electromagnetic field emitted by the phone in those regions.

"Although we cannot determine the clinical significance, our results give evidence that the human brain is sensitive to the effects of radiofrequency-electromagnetic fields from acute cell phone exposures," said Nora Volkow, MD, MD, of the National Institutes of Health and the study's lead author.

Between January 1 and December 31, 2009, scientists conducted the study in 47 healthy individuals. All participants had two scans done on separate days, and on both days, prior to the scans, two cell phones, one placed on the left and one on the right ear, were used so subjects wouldn not know which cell phone was active.

For one of the days both cell phones were off. For the other day the right cell phone was on but muted while receiving a call from a recorded text. The order of conditions was randomly assigned, and participants did not know when an active phone was being tested.

The study was also carried out with the phone muted to avoid confounding effects from auditory stimulation, nonetheless, along with previous investigations, the research provides further reason to believe that additional investigations are necessary.

Previous investigations measuring cerebral blood flow monitored by positron emission tomography (PET), have had inconsistent results.

In this study, there were no differences in overall brain metabolism between the on and off conditions, but during the on condition, the specific regions of the brain closest to the phone's antenna showed significant increases in brain glucose metabolism.

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