Several cell phone studies have been conducted over the years in an attempt to conclude whether the mobile devices cause any long-term effects to those who use them. So far, no one has been successful in this quest, but the National Institutes of Health have now conducted a new study claiming that the radiation from these devices can actually increase brain activity. 

Dr. Nora Volkow, study leader and a researcher at the National Institute of Drug Abuse, and a team of researchers, may have found a direct effect that cell phones have on the human brain, suggesting that 50 minutes or more of cell phone use can boost brain activity.  

Previous studies have tried to show that cell phones are linked to tumors or cancer in the brain, but none of them have provided a conclusive link between cell phone radiations and complications in the brain. For instance, the Interphone study, which was the largest study regarding cell phones and their effects that was released in May 2010, found no long-term risks linking cell phones to brain tumors. 

On the other hand, in 2008, Director of Cancer Research at the University of Pittsburgh Dr. Ronald Herberman released a memo to his staff to warn them about potential cell phone harm. The memo stated that while cell phone-related effects remained controversial, Herberman was convinced that a sufficient amount of data was available to issue a warning and offer "precautionary advice" regarding the devices. 

"Some studies have shown a significant association with cancer, others show the opposite," said Volkow. "When you have data that is inconsistent, there is uncertainty, and uncertainty of course generates fear." 

What Volkow and her team found was that extended use of a mobile device does increase brain activity. 

"There have been several studies since the 1990's trying to address whether the human brain is affected by the electromagnetic radiation from cell phones because it's very, very weak," said Volkow. "The studies were very inconsistent, but we designed this study so it would be powered to detect small activity. This shows that the human brain is sensitive to these weak magnetic pulses." 

This particular study consisted of 47 test subjects who used cell phones for various periods of time. Using PET scans, researchers measured the brain activity of these test subjects when the phone was off, on, muted and held to the ear. What they found was that more than 50 minutes of exposure to an in-use cell phone causes increased brain activity by about 7 percent in areas near the antenna.  

Researchers were able to find this by measuring the brain's consumption of glucose instead of measuring cerebral blood flow like other studies have in the past. 

"What we showed is glucose metabolism increases in the brain in people who were exposed to a cell phone in the area closest to the antenna," said Volkow.  

Volkow concluded that it is unknown whether this increased brain activity is harmful or not, but the study finally provides insight into the fact that cell phone radiation does, in fact, affect the human brain in some way. The team plans to continue researching this topic to see exactly what this increased brain activity means.  

According to Nielsen industry statistics, the number of cell phone users ages 13 and up has increased from 7.6 million in 1991 to 223 million in 2010.

This study was published in The Journal of the American Medical Association.