A study by the University of Waterloo found that strong multilingualism, linked to enhanced executive function, may inhibit cognitive deficits and decrease the risk of developing dementia. The results were published in the Journal of Alzheimer’s Disease.
In the study, a team of researchers examined the cognitive health of 325 Roman Catholic nuns associated with the Sisters of Notre Dame based in the US. They also collected data from the Nun Study, a continuing longitudinal, international study. All participants were aged 75 and over.
The findings showed that multilingualism did not slow the onset of dementia, but did reduce the risk of developing the disease if participants spoke four or more languages. Only six percent of the nuns who spoke four or more languages developed dementia, compared to 31 percent of participants with the ability to have spoken only one language.
“Language is a complex ability of the human brain, and switching between different languages takes cognitive flexibility. So it makes sense that the extra mental exercise multilinguals would get from speaking four or more languages might help their brains be in better shape than monolinguals,” said Suzanne Tyas, lead researcher of the study.
“The Nun Study is unique: It is a natural experiment, with very different lives in childhood and adolescence before entering the convent, contrasted with very similar adult lives in the convent,” Tyas added.
“This gives us the ability to look at early-life factors on health later in life without worrying about all the other factors, such as socioeconomic status and genetics, which usually vary from person to person during adulthood and can weaken other studies.”
“The impact of language on dementia may extend beyond number of languages spoken to encompass other indicators of linguistic ability. Further research to identify the characteristics of multilingualism most salient for risk of dementia could clarify the value, target audience, and design of interventions to promote multilingualism and other linguistic training as a strategy to reduce the risk of dementia and its individual and societal impacts,” the study concluded.