Speaking two languages can delay the onset of Alzheimer's disease, research suggests.
WASHINGTON DC: Being bilingual dramatically slows the advance of Alzheimer's disease in the brain and may provide protection against the deterioration seen during ageing, researchers say.
Even learning a second language later in life delays the decline important brain functions, Ellen Bialystok of York University in Toronto, Canada, told reporters at the annual meeting of the American Association for the Advancement of Science currently meeting in Washington DC.
She said that a set of cognitive processes known as the 'executive control system' - which allows us to think in complex ways and controls the allocation of attention - is enhanced in people who are actively bilingual throughout their lives.
Bialystok's group identified this enhancement in the brains of children, adults and older people, the latter being when this system begins a natural decline.
450 sufferers studied
Bialystok's group studied 450 sufferers of Alzheimer's disease: half of them were bilingual, and the other half spoke only one language.
Researchers know that the disease attacks the median temporal area of the brain at the steady predictable rate.
Yet, despite all of the patients being selected for the same level of impairment, those who spoke two languages were, on average, diagnosed with Alzheimer's 4.3 years later and reported the onset of symptoms 5.1 years later than patients who were monolingual.
"Which means they've been able to cope with the disease [for longer]," Bialystok said, adding that being bilingual "is protecting older adults, even after Alzheimer's disease is beginning to affect cognitive functioning. Bilinguals can continue to function, even though there's damaged brain tissue."
Cognitive decline is slower
Another study, as yet published, used computed tomography 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, Bialystok said.
"One of the reasons bilingualism has these powerful mechanisms - including protecting against early symptoms of dementia - is because it's one way to keep your brain active," she told reporters.
