It is thought that speaking more than one language might help the brain build up reserves that help it cope better when Alzheimer's symptoms hit. (Siu Chiu/Reuters)

There's more evidence that picking up a second language may help delay the onset of Alzheimer's symptoms, Canadian researchers have found.

The study in Tuesday's issue of the journal Neurology looked at the medical records of 211 patients diagnosed with probable Alzheimer's disease and found those who have spoken two or more languages consistently over many years experienced a delay in the onset of their symptoms by as much as five years.

It is thought that speaking more than one language might help the brain build up reserves that help it cope better when Alzheimer's symptoms hit, the researchers said.

"The present data confirm results from an earlier study, and thus we conclude that lifelong bilingualism confers protection against the onset of Alzheimer's disease," the study's authors concluded.

The researchers stressed they are not claiming that bilingualism prevents Alzheimer's or other dementias.

Rather, bilingualism appears to contribute to "cognitive reserve," which helps the brain to compensate and delay the onset of symptoms, said the study's lead investigator, Dr. Fergus Craik of the Rotman Research Institute.

The brains of people who speak two languages still show deterioration from Alzheimer's.

The study looked at patients at Baycrest in Toronto from 2007 to 2009.

Information including date of diagnosis, age of onset of cognitive impairment, occupational history, education and language fluency were recorded. The researchers classified 102 subjects as bilingual and 109 as monolingual.

Symptoms of Alzheimer's include memory loss, confusion, and difficulties with problem-solving and planning. There are currently no drug treatments that delay symptoms.

This study was funded by the Canadian Institutes of Health Research, the Alzheimer Society of Canada and the ShaRna Foundation.