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Bilingualism ‘keeps dementia at bay’

Jasmin Fox-Skelly on why learning an extra language can help keep your brain healthy

APRIL brain

INSIDE OUT Scans showing uptake of proteins in a human brain affected by neuro-degenerative diseases such as Alzheimer’s (Courtesy IMC Groningen)


Speaking two languages can improve your cognitive skills and delay the onset of dementia, and it’s never too late to learn, according to recent research.


Over the last decade more and more evidence has highlighted the benefits of being bilingual. Juggling two languages can exercise the brain, making bilinguals better at certain mental tasks such as prioritising and multi-tasking. Several studies have also linked bilingualism to improved working memory, which is associated with both reading and maths skills. Psychologist César Ávila Rivera at the University of Castellón in Spain found in 2010 that bilingual adults are quicker and more efficient at certain tasks involving the use of skills known as executive functions, such as planning and problem solving.


Modern imaging techniques have also allowed scientists to compare the brains of bilingual children with their monolingual peers. It seems that although language areas develop similarly, certain regions, such as the inferior frontal cortex (which is involved with both language and thinking skills) appear to be more active in bilingual children when they are reading.


It seems that being bilingual may also help keep the brain younger for longer, keeping dementia at bay. In 2007 a Canadian study found that people fluent in two languages tended to display the first symptoms of Alzheimer’s four to five years after people who spoke just one language.
Ellen Bialystok, lead author of the study, later scanned the brains of 450 Alzheimer’s patients and found that although the patients all displayed a similar degree of cognitive function the bilingual subjects’ brains showed less atrophy and damage in regions involved in long-term memory, language recognition and auditory perception. This suggests that being bilingual somehow protects the brain from cognitive decline, despite it continuing to degenerate.


Many of the bilinguals in Ellen Bialystok’s study had migrated to Canada from another country, meaning it was unclear whether education or migration status had played a part in her results. To rule out this possibility, in 2013 Thomas Bak from the University of Edinburgh studied dementia patients in India, a country where multilingualism is part of everyday life. Most Indians have a home language (either Telugu or Dakkhini in the Bak study) and a link language – increasingly English, but also India’s other national language, Hindi.


Out of 650 people who had been diagnosed with dementia over six years about half spoke at least two languages. This group’s symptoms again started on average four and a half years later than those in people who were monolingual. The study found that being bilingual helped stave off Alzheimer’s disease and other types of dementia as well.


What is more, the benefits of speaking two languages were felt even for those who were illiterate, suggesting that education is not responsible. Even more recently a study at Ghent University in Belgium compared a group of 69 monolingual (all but one monolingual Dutch speakers, the other francophone only) and 65 bilingual Belgian patients (speaking both French and Dutch) suffering from Alzheimer’s. They again found that speaking a second language appeared to delay the first symptoms by four to five years. The average age of diagnosis for the patients was 73 for a monolingual person and 77 for a bilingual person.


Although many people who are bilingual have grown up so, research shows that it is never too late to learn a second language and that you can enjoy the cognitive advantages it brings even if you learn late into adulthood.


The Lothian Birth Cohort study tracked the lives of 1,100 people born in Edinburgh in 1936. All were monolingual English speakers at eleven when they undertook a series of cognitive tests. As part of an academic study, Dr Thomas Bak caught up with 853 of them when they were in their early seventies and gave them cognitive tests. About one third of the group had gone on to study at least one further language, and 65 of them had learned it after the age of eighteen.


Those who had studied another language performed better in their cognitive tests than would be expected from the tests they had taken aged eleven, particularly in general intelligence and reading. This suggests that the benefits are down to language learning, as if they were simply down to intelligence one would expect an increase in all skills, not just intelligence and reading. Bak found that the benefits of studying a second language to the brain were comparable to physical activity or not smoking.


When it comes to the science behind how learning a second language improves cognitive ability, delays dementia and keeps the brain young and agile for longer, the jury is still out. One idea is that constantly juggling and choosing between words in two different languages is like a workout for the brain, keeping connections active and stopping brain cells from dying. As bilingual speakers are always practising a kind of brain gymnastics by having to select the correct language and suppress the other, this stimulates many different parts of the brain and builds up the brain’s overall capacity for thought, increasing its so-called cognitive reserve.


‘For me language is the equivalent of swimming,’ says Bak. ‘When swimming you use all your body’s muscles, and when speaking you use almost all areas of your brain. Bilinguals negotiate constantly between different sounds, words, concepts, grammatical structures and social norms associated with the languages they speak. This is bound to provide permanent, intensive and versatile mental training.’

 

Jasmin Fox-Skelly is a freelance science writer based in Cardiff in the UK