According to Reuters, in a study conducted on 15 young male volunteers, Dr. Paolo Rossini and colleagues used Transcranial Magnetic Stimulation or TMS to check brain function while people used a GSM 900 cell phone for 45 minutes.
They found that in 12 of the volunteers, the cells in the motor cortex adjacent to the cell phone showed excitability during phone use but returned to normal within an hour.
The cortex is the outside layer of the brain and the motor cortex is known as the "excitable area" because magnetic stimulation has been shown to cause a muscle twitch.
Adding to the concerns over the mobile safety, the study suggests that people with conditions such as epilepsy, linked with brain cell excitability, could potentially be affected by the cell phone emissions.
Though, researchers stressed that they had not shown that using a cell phone is bad for the brain in any way.
In the study published in the Annals of Neurology, researchers wrote: "It should be argued that long-lasting and repeated exposure to EMFs (electromagnetic frequencies) linked with intense use of cellular phones in daily life might be harmful or beneficial in brain-diseased subjects."
"Further studies are needed to better circumstantiate these conditions and to provide safe rules for the use of this increasingly more widespread device."
Earlier medical studies on cell phone use have provided mixed results. Swedish researchers found last year that using cell phones over time can raise the risk of brain tumors. But a study by Japan's four mobile telephone operators found no evidence that radio waves from the phones harmed cells or DNA.
The Dutch Health Council analyzed several studies and found no evidence that radiation from mobile phones was harmful.
