Speaking two languages may stave off the onset of dementia in the aging brain – at least for about 4 or 5 years. It’s a great way to buff up your brain and keep it active.
More than 5 million Americans have Alzheimer's disease, and it’s the fifth-leading cause of death. Now, new research shows that lifelong bilingualism is a one of the things that contributes to our ‘cognitive reserve,’ which makes up for the brain pathologies we accumulate with age.
“It is rather like a reserve tank in a car,” says study author Ellen Bialystok Bialystok of York University. “When you run out of fuel, you can keep going for longer because there is a bit more in the safety tank.”
Learning and speaking two languages requires the brain to work harder, which helps keep it nimble. It's the same use-it-or-lose-it reasoning that underlies advice to do crossword puzzles and to continue to learn new skills throughout life – the idea is to help the brain create and maintain more neural connections. Brains with more cognitive reserve – and therefore more flexibility and executive control – are thought to be better able to compensate for the loss of neurons associated with Alzheimer's.
Bialystok and colleagues from the Rotman Research Institute at Baycrest looked at data from 211 patients diagnosed with probable Alzheimer’s disease. Of them, 102 are bilingual and 109 are monolingual.
The bilingual patients were diagnosed 4 years later – and reported the onset of symptoms 5 years later than the monolingual patients.
On average, monolingual patients made their first doctor’s appointment to address Alzheimer’s symptoms at age 71.4, compared with 75.5 for bilingual people. Monolingual people first reported symptoms at 75.4 compared with closer to 80 for the bilingual.
“Bilingual adults are better able to cope with the disease’s effects on mental function,” proposes Bialystok, who cautions that knowing another language doesn’t stop Alzheimer’s completely, just delays its impact.
According to an unpublished study, computed tomography (CT) scans to show that bilinguals had the same level of cognitive decline as monolinguals even when the people who spoke multiple languages were at a more advanced stage of Alzheimer's [AFP].
"Every little bit helps. The longer you've been bilingual, the more you use all your languages, the more fluent you are, all of those things contribute,” Bialystok says. "Even if you're starting to learn a language at 40, 50, or 60, you're unlikely to become bilingual, but you are keeping your brain active. So you're contributing to cognitive reserve through very engaging and intense activity.”
The study was published in Neurology and presented at the American Association for the Advancement of Science (AAAS) meeting in Washington, DC this past weekend.
Image: Rosetta Stone