Learning another language could help delay the onset of Alzheimer's disease by up to five years, according to research presented at the American Association for the Advancement of Science last week.
The study was carried out on 211 Alzheimer's sufferers by a team of Canadian researchers, including Dr. Ellen Bialystok, a psychology professor from University of York in Toronto. Age at onset of cognitive impairment was recorded, along with language history, with 102 patients classified as bilingual and 109 as monolingual.
The team found that the bilingual patients had been diagnosed an average of 4.3 years later and had reported the onset of symptoms 5.1 years later than the monolingual patients. There appeared to be no effect from other factors such as education, gender, occupational status, or immigration.
Bialystok said in a York University press release that bilingualism does not prevent Alzheimer's disease, because bilingual patients still showed brain deterioration and impairment, measured using CT brain scans.
“Instead, our results show that people who have been lifelong bilinguals have built up a cognitive reserve that allows them to cope with the disease for a longer period of time before showing symptoms,” Bialystok said.
The ability of patients to speak more than one language appears to "contribute to cognitive reserve, which acts to compensate for the accumulation of amyloid and other brain pathologies," according to the study. These compensatory skills can combat symptoms such as memory loss and confusion.
“Overall, bilingualism should be seen as an important tool for healthy aging, along with exercise, diet, and other lifestyle choices,” Bialystok said. “It’s also another reason to encourage people in multicultural societies like ours to keep speaking their native tongue and pass it along to their children."
"Once the disease begins to compromise this region of the brain, bilinguals can continue to function," Bialystok said, according to Fox News. "Bilingualism is protecting older adults, even after Alzheimer's disease is beginning to affect cognitive function."
The study suggests that maintaining an active lifestyle in terms of social, mental, and physical engagement can help to protect against the development of dementia by contributing to "cognitive reserve."
Some of the study's findings are published in the November 9, 2010 issue of the journal Neurology.