A study in mice suggests using cellphones may help prevent some of the brain-wasting effects of Alzheimer's disease, U.S. researchers said on Wednesday.

After long-term exposure to electromagnetic waves such as those used in cell phones, mice genetically altered to develop Alzheimer's performed as well on memory and thinking skill tests as healthy mice, the researchers wrote in the Journal of Alzheimer's Disease.

The results were a major surprise and open the possibility of developing a noninvasive, drug-free treatment for Alzheimer's, said lead author Gary Arendash of the University of South Florida.

He said he had expected cell phone exposure to increase the effects of dementia.

Quite to the contrary, those mice were protected if the cell phone exposure was stared in early adulthood. Or if the cellphone exposure was started after they were already memory- impaired, it reversed that impairment, Arendash said in a telephone interview.

Arendash's team exposed the mice to electromagnetic waves equivalent to those emitted by a cellphone pressed against a human head for two hours daily over seven to nine months.

At the end of that time, they found cellphone exposure erased a build-up of beta amyloid, a protein that serves as a hallmark of Alzheimer's disease.

The Alzheimer's mice showed improvement and had reversal of their brain pathology, he said.

It (the electromagnetic wave) prevents the aggregation of that bad protein of the brain, Arendash said. The findings are intriguing to us because they open up a whole new field in neuroscience, we believe, which is the long-term effects of electromagnetic fields on memory.

Arendash said his team was modifying the experiment to see if they could produce faster results and begin testing humans.

Despite decades of research, there are few effective treatments and no cure for Alzheimer's, the most common form of dementia. Many treatments that have shown promise in mice have had little effect on humans.

More than 35 million people globally will suffer from Alzheimer's disease or other forms of dementia in 2010, according to the Alzheimer's Association.

There has been recent controversy about whether electromagnetic waves from cellphones cause brain cancer.

Co-author Chuanhai Cao said the mice study is more evidence that long-term cellphone use is not harmful to the brain.

Groups such as the World Health Organization, the American Cancer Society, and the National Institutes of Health, have all concluded that scientific evidence to date does not support any adverse health effects associated with the use of cellphones.

(Editing by Alan Elsner)