Parlez-vous français? Learning another language may stave off Alzheimer’s and other types of dementia – and it’s never too late to start.
Bilingualism was the deferral of dementia in 2007, when at York University in Toronto and her colleagues examined the records of people who had been referred to a memory clinic and diagnosed with dementia. Of the 184 people in their analysis, symptoms appeared four years later in those who were bilingual than in their monolingual peers.
Further studies replicated these findings, but some scientists questioned whether bilingualism was merely a proxy for other lifestyles factors, such as having more money or a better diet. “The confounding factors make the literature messy,” says at McGill University in Montreal.
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Researchers have since found a way through the mess. In 2013, at the National Institute for Mental Health and Neurosciences in Bangalore, India, and her colleagues showed that bilingual people developed dementia than monolingual individuals, regardless of their education, occupation, sex or immigration status. “What is emerging consistently,” says Phillips, “is that older adults who speak more than one language have clear advantages against dementia.”
The answer as to why is still incomplete, in part because there are so many ways people can use a second language, for instance, they may speak it with only one person or for just a few years or decades. However, recent imaging studies have given us a clearer idea of what’s going on.
It comes down to brain resilience, says Phillips, which bilingualism seems to help in three ways. First, it boosts your brain reserve, or its size. If you assume that cognitive deficits associated with dementia occur at a fixed threshold of damage, a person with a greater brain reserve can sustain more damage before reaching that threshold. People who are bilingual have language areas, such as the inferior frontal gyrus, and in learning and emotion regions, such as the basal ganglia.
Being bilingual also benefits your cognitive reserve – the efficiency and adaptability of your brain. Someone with a high cognitive reserve can use different pathways to access the same information in the face of brain atrophy. “If you think of brain reserve versus cognitive reserve, it’s like comparing a hardware advantage with a software advantage,” says Phillips.
Bilingualism is thought to boost cognitive reserve in part because of the constant competition between languages in the brain. For example, when someone who speaks English and French hears “for”, their brain activates pathways for related words in both languages, such as “forage” and “´Ú´Ç°ůĂŞłŮ”, meaning forest. This constant switching and inhibiting of pathways strengthens aspects of cognitive reserve known as executive functions – a suite of abilities that include decision-making, planning and attention.
Supporting this idea, bilingual people can actually show in brain areas affected by Alzheimer’s disease than monolingual individuals, despite no difference in cognitive function, which suggests that their cognitive reserve is higher to begin with.
Finally, we have brain maintenance, which refers to biological processes that keep your brain healthy when faced with pathological effects. Last September, Phillips’s team showed a link between by studying bilingual and monolingual people who had early- or late-stage Alzheimer’s, as well as individuals who felt like their memory was getting worse but who had no objective evidence of dementia.
The team found differences in the hippocampus, with bilingual people showing less decline in this region as cognitive problems progressed. “I found this tremendously interesting because the hippocampus is not a language centre, it is the primary memory centre,” says Bialystok.
But there was no difference in hippocampal volume between monolingual and bilingual participants without signs of disease, which suggests that knowing two languages helps maintain the hippocampus when damage occurs, rather than increasing its size beforehand.
“What this all says is that bilingualism changes the way you cope with an increasingly compromised brain,” says Bialystok. “It doesn’t prevent dementia, it holds back the flood. When bilingual people eventually show cognitive problems, they decline faster, but it starts later. Imagine what families could do with that extra time.”
If reading this article in English is all you are capable of, rest assured it may not be too late. is associated with the protection offered, but “learning another language during adulthood [still] provides benefits to brain health,” says Viorica Marian, who studies multilingualism at Northwestern University in Evanston, Illinois.
Nevertheless, the longer you can speak the second language for, the better, says Bialystok. “What you’re doing is giving your brain tremendous stimulation, and the bottom line is what’s hard for your brain is good for your brain.”
And don’t feel you need to master French, German and Spanish. “There’s no empirical evidence that more languages offer more protection,” says Bialystok.
