In a new study, researchers found a strong ability in languages may help reduce the risk of developing dementia.
The research was conducted by a team from the University of Waterloo.
The team examined the health outcomes of 325 Roman Catholic nuns who were members of the Sisters of Notre Dame in the United States.
The data was drawn from a larger, internationally recognized study examining the Sisters, known as the Nun Study.
The researchers found that 6% of the nuns who spoke four or more languages developed dementia, compared to 31% of those who only spoke one.
However, knowing two or three languages did not reduce the risk in this study, which differs from some previous research.
The team says 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 multilingual would get from speaking four or more languages might help their brains be in better shape than monolinguals.
The researchers also examined 106 samples of the nuns’ written work and compared it to the broader findings.
They found that written linguistic ability affected whether the individuals were at greater risk of developing dementia.
For example, idea density—the number of ideas expressed succinctly in written work—helped reduce the risk even more than multilingualism.
This study shows that while multilingualism may be important, we should also be looking further into other examples of linguistic ability.
Future work needs to examine more about multilingualism and what aspects are important—such as the age when a language is first learned, how often each language is spoken, and how similar or different these languages are.
This knowledge can guide strategies to promote multilingualism and other linguistic training to reduce the risk of developing dementia.
The lead author of the study is Suzanne Tyas, a public health professor at Waterloo.
The study is published in the Journal of Alzheimer’s Disease.
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