Speaking several languages may help protect your brain against developing dementia. A new study examined a group of Roman Catholic nuns, aiming to find out how the risk of dementia changed based on their language abilities.
The Nun Study
The researchers followed 325 nuns at the Sisters of Notre Dame, as part of a larger study known as the Nun Study. The results showed that of the nuns who spoke four or more languages, only six percent developed dementia. Meanwhile, 31 percent of nuns who spoke only one language developed dementia.
“Language is a complex ability of the human brain, and switching between different languages takes cognitive flexibility,” Suzanne Tyas, a public health professor at the University of Waterloo and lead author of the study, said in a press release. “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.”
Interestingly, however, there wasn’t much of a difference between nuns who spoke one language and those who spoke two to three. It was the people who spoke at least four who saw the biggest decrease in dementia risk.
“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 said.
“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 researchers also tracked how other cognitive abilities — like writing — contributed to dementia risk. It turns out that written linguistic ability, and particularly idea density (being able to express ideas well in writing) was actually the strongest predictor of developing dementia.
“The impact of language on dementia may extend beyond number of languages spoken to encompass other indicators of linguistic ability,” the authors wrote in the conclusion.
Languages and Dementia Risk
The latest study builds on past evidence that language ability may play a role in staving off cognitive decline. One past study found that knowing two languages increased cortical thickness and grey matter density in the brain, which has been associated with a boost in brain health. Research has also shown that things like reading could help your memory and prevent dementia.
However, as each case of dementia is different, being educated, multilingual or an avid reader may not always make a huge difference. Another recent study found that higher levels of education did not necessarily slow down dementia progression once it had started.
Still, researchers are hoping to understand how speaking several languages can have a positive influence on your brain. This is something Tyas hopes to investigate further in future research.
“We need to know 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,” Tyas said. “This knowledge can guide strategics to promote multilingualism and other linguistic training to reduce the risk of developing dementia.”