A new study suggests that bilingual speakers hold Alzheimer’s disease at bay for an extra four years on average compared with people who spoke only one language. Knowing more languages can improve cognitive skills and delay the onset of dementia, according to researchers.
Ellen Bialystok, a psychologist at York University in Toronto added that bilingual children who use their second language regularly are better at prioritising tasks and multitasking compared with monolingual children. Bialystok said on Friday at the annual meeting of the American Association for the Advancement of Science in Washington, DC, “Being bilingual has certain cognitive benefits and boosts the performance of the brain, especially one of the most important areas known as the executive control system…We know that this system deteriorates with age but we have found that at every stage of life it functions better in bilinguals. They perform at a higher level. It won’t stop them getting Alzheimer's disease, but they can cope with the disease for longer.”
Her study was published recently in the journal Neurology. She and her team looked at 211 people with probable Alzheimer’s disease, 102 of whom were bilingual and 109 monolingual, and noted the age at which the patients' cognitive impairment had started. Her results showed that bilingual patients had been diagnosed 4.3 years later, on average, and had reported onset of symptoms 5.1 years later than monolingual patients.
She explained that switching between different languages seems to stimulate the brain so that it builds up a cognitive reserve. “It is rather like a reserve tank in a car. When you run out of fuel, you can keep going for longer because there is a bit more in the safety tank.” The effect was greatest for people who had to use the language every day and choose between two sets of words all the time. Nevertheless, learning a language at school and continuing to practice it was also useful, she said. “It works best for people who speak two languages every day, like immigrants moving to a new country who speak their own language at home. But every little bit helps.”
The team is now researching whether using two or more languages resulted in any physical changes to the brain, in addition to improving cognition. Early results suggest that it may change brain size.
In yet another study carried out by Judith Kroll, a psychologist at Penn State University, it was noted that speaking more than one language keeps the brain in shape and bolsters mental function. She found that bilingual speakers could outperform single-language speakers in mental tasks such as editing out irrelevant information and focusing on important details. Bilinguals were also better at prioritizing and multi-tasking, she said.
She added, “We would probably refer to most of these cognitive advantages as multi-tasking… Bilinguals seem to be better at this type of perspective-taking.” Her findings conflict with the idea that speaking several languages confuses the brain and might even hinder cognitive development. “The received wisdom was that bilingualism created confusion, especially in children. The belief was that people who could speak two or more languages had difficulty using either. The bottom line is that bilingualism is good for you.” “The important thing that we have found is that both languages are open for bilinguals. In other words, there are alternatives available in both languages,” said Kroll. “Even though language choices may be on the tip of their tongue, bilinguals rarely make a wrong choice…The bilingual is somehow able to negotiate between the competition of the languages…The speculation is that these cognitive skills come from this juggling of languages.”
Amy Weinberg a professor of linguistics of the University of Maryland said at the conference, “Getting to some level of proficiency in a second language certainly makes you an expert multi-tasker… When you’re speaking, all the languages you speak are turned on, and you have to activate a mechanism in the brain that allows you to limit interference from one language when talking in the other… You’re juggling all kinds of mental balls as a bilingual.”
“The evidence that we have is not only with very early bilinguals,” said psychologist Teresa Bajo of the University of Granada in Spain, who was not involved in Bialystok’s research. “Even late bilinguals use these very same processes so they may have also the very same advantages.” Bialystok said, “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.”
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