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November 06, 2013

Speaking More than One Language May Delay Onset of Dementia

by Jessica Berman

New research suggests that speaking more than one language may delay the onset of different types of dementia.  In fact, say investigators, bilingualism appears to be more important than the level of education in warding off dementias.  

In a study carried out in India, researchers assessed the effect of bilingualism in delaying the onset of Alzheimer’s disease, frontotemporal dementia, which tends to strike people at a younger age, vascular dementia, Lewy bodies dementia and mixed dementias.  Nearly 650 people with an average age of 66 were studied, and 240 suffered from Alzheimer’s disease, the most common form of mental decline.
 
Three hundred ninety-one of the participants spoke two or more languages.  Investigators found the dementias began about four-and-a-half years later in those who were bilingual compared to those who only spoke only one language.  The volunteers’ level of education had no effect on the outcome.

Co-author Thomas Bak of the Center of Cognitive Aging at the University of Edinburgh in Scotland speculates that those who are fluent in more than one language train their brains by switching back and forth between different words and expressions.  

Bok believes this concentration improves so-called executive functioning or attention to tasks, which tends to decline in people with dementias.

“I am suppressing the other languages.  So it means I have to be always active, selectively activating things.  And we believe that because this attention mechanism is important in different types of dementia, that is why we find this effect in different types of dementia," said Bak.

Researchers found there was no benefit in speaking more than two languages.  They also did not see a delay in the onset of Lewy bodies dementia, a progressive form of mental illness that causes hallucinations and causes sufferers to fluctuate back and forth between alertness and periods of drowsiness.

To reap the benefits, Bak says it does not appear to matter whether you learn a language at a young age or later in life.

“So it’s not something you sort of say that '[if] you missed the boat when you do not do it as a baby.'  It is something that is still quite useful and powerful when you do it as an adult," he said.

Scientists found that the benefits of bilingualism in delaying the onset of dementia occurred even in uneducated subjects.

An article on the benefits of bilingualism on dementias in published in the journal Neurology.