Can you speak two or more languages? If so, your brain may thank you for it later in life. New research published in the Annals of Neurology suggests that bilingualism may slow down age-related cognitive decline - even if a second language is learned in adulthood.
The research team, led by Dr. Thomas Bak of the Centre for Cognitive Aging and Cognitive Epidemiology at the University of Edinburgh in the UK, notes that recent studies have already indicated a link between bilingualism and delayed onset of cognitive decline and dementia.
But according to Dr. Bak: "Our study is the first to examine whether learning a second language impacts cognitive performance later in life while controlling for childhood intelligence."
The team assessed data from the Lothian Birth Cohort 1936, which involved 835 native English speakers who were born and resided in Scotland in the UK.
In 1947 - when the participants were approximately 11 years old - they completed a test measuring their levels of intelligence and cognitive ability. The test was repeated between 2008 and 2010, when the participants reached their early 70s. As part of the test, subjects were asked whether they could speak at least one language other than English.
Bilingual participants exceeded later-life cognitive expectations
Of the 835 participants tested, 262 were able to speak two or more languages. Of these, 195 learned a second language before the age of 18 (19 before the age of 11) while 65 learned a second language after the age 18.
On comparing participants' cognitive abilities at older age with their predicted later-life cognitive abilities when the study began, the researchers found that those who were bilingual exceeded expectations - particularly in the areas of reading and general intelligence - compared with those who only spoke English.
In addition, the team says this finding was prominent even among participants who learned their second language after the age of 18.
Commenting on the study results, Dr. Bak says:
"These findings are of considerable practical relevance. Millions of people around the world acquire their second language later in life. Our study shows that bilingualism, even when acquired in adulthood, may benefit the aging brain."
The researchers point out that their study does have some limitations. For example, the ability to speak a second language was determined by a questionnaire rather than aptitude tests, which could have influenced results.
Not too late to learn another language: researchers say speaking another language - even if it is learned in adulthood - may stave off later-life cognitive decline.
In addition, only few participants learned a second language before the age of 11, "so we could not study the classical cases of parallel, perfect, early acquisition of both languages," they note.
However, they say that this particular limitation was also a strength of the study, pointing out that millions of people learn a second language later in life, whether at school, university, work or as a result of migration.
"Many never reach native-like perfection," the researchers add. "For this population, our results are particularly relevant; bilingualism in its broad definition, even if acquired in adulthood, might have beneficial effects on cognition independent of childhood intelligence."
This latest research supports a study reported by Medical News Today last year, which suggested that the brains of bilingual older adults work faster and more efficiently than brains of seniors who only speak one language.