The surprise findings contradict some previous studies that have suggested mobiles can cause Alzheimer’s and brain cancer.
But Professor Gary Arendash, of South Florida University, and colleagues say long-term mobile use improves the function of the organ instead of causing any damage following their study of mice.
Prof Arendash said: “It surprised us to find that cellphone exposure, begun in early adulthood, protects the memory of mice otherwise destined to develop Alzheimer’s symptoms.
“It was even more astonishing that the electromagnetic waves generated by cell phones actually reversed memory impairment in old Alzheimer’s mice.”
The study published in the Journal of Alzheimer’s Disease involved 96 mice – some of which were genetically altered to develop memory problems mimicking Alzheimer’s as they aged.
Both the normal rodents and those with Alzheimer’s were exposed to the electromagnetic field generated by standard mobiles use for two one-hour periods each day for seven to nine months.
This was done by arranging their cages around a centrally-located antenna emitting electromagnetic waves typically emitted by a mobile phone pressed up against a human head.
If the exposure was started when the genetically-programmed mice were young adults – before signs of memory impairment were apparent – their cognitive ability was protected.
The Alzheimer’s mice performed as well on tests measuring memory and thinking skills such as negotiating a maze as aged mice without dementia.
If older Alzheimer’s mice already exhibiting memory problems were exposed to the electromagnetic waves their memory impairment disappeared.
Months of exposure even boosted the memories of normal mice to above-normal levels.
But the memory benefits of exposure took months to show up – suggesting a similar effect in humans would take years of usage.
Human skulls are also much thicker than mice and this could prevent the waves from impregnating the brain.
However Prof Arendash said: “Since we selected electromagnetic parameters that were identical to human cell phone use and tested mice in a task closely analogous to a human memory test, we believe our findings could have considerable relevance to humans.”
Rebecca Wood, Chief Executive of the Alzheimer’s Research Trust, said more research was needed to see if it would be effective on humans.
“This research has been carried out in mice that mimic some of the symptoms of Alzheimer’s in people, so we don’t know if any similar effects will be seen in humans,” she said.
“Although the researchers hope their findings will translate to people, much more research is needed to find out if there could be any beneficial effects of long-term exposure to electromagnetism, and to guarantee its safety.
“We don’t recommend spending 24 hours a day on a mobile phone – we don’t know the long-term effects, and bills could go through the roof. ”
