BEING ABLE to speak two languages can delay the onset of dementia in older people. The changes in the brain seen in bilingual subjects also makes them better multitaskers, more able to switch easily from one mental task to another, research has shown.
Details were presented yesterday at the American Association for the Advancement of Science’s annual meeting, taking place in Washington. It formed part of an intriguing session entitled: “Does speaking two languages improve your brain?”
The conclusive answer seems to be yes, given the results of a study by Prof Ellen Bialystok of York University in Toronto. She and colleagues are studying a group of 450 Alzheimer’s patients, half of whom are monolingual and half bilingual. As subjects were brought onto the study they were assessed by age, cognitive level at the time of Alzheimer’s diagnosis and other aspects. Their rate of decline was assessed over time.
“The bilinguals were on average four to five years older, which means they have been able to cope with the disease,” Prof Bialystok said. They were able to function better than matched monolinguals, even though they had begun to develop the brain tissue damage associated with Alzheimer’s disease, she added.
“The reason bilingualism has these powerful effects, including potentially against dementia, has to do with cognitive reserve. Bilingualism is a way of keeping your brain active,” Prof Bialystok said.
Cognitive reserve refers to a key function of the brain, the “executive control system”, she said. “It is the most important part of your mind.” It allows your mind to filter out extraneous information while locking onto the important details.
It is also the part of the brain which allows a bilingual person to maintain control of one language while speaking, and to suppress the second language.
The executive control system is different in those with one language from those with two, she said. “This executive control system is enhanced in people who are actively bilingual in their early life.”
This linguistic superiority can be detected all through a person’s life.
A researcher from Canada described her studies into how a newborn was quickly able to distinguish between two languages spoken by bilingual parents.
Prof Janet Werker of the University of British Columbia, Vancouver, demonstrated that babies just months old can separate the two languages.