Bilinguals may be better equipped to fight dementia: study

Bilinguals may be better at saving brain power and are equipped to stave off cognitive ageing or dementia, a new study has found.

Researchers from the University of Montreal in Canada compared what are known as functional brain connections between seniors who are monolingual and seniors who are bilingual.

They established that years of bilingualism change how the brain carries out tasks that require concentrating on one piece of information without becoming distracted by other information. This makes the brain more efficient and economical with its resources.

To arrive at this finding, they asked two groups of seniors - one of monolinguals and one of bilinguals - to perform a task that involved focusing on visual information while ignoring spatial information.

The researchers compared the networks between different brain areas as people did the task.

They found that monolinguals recruited a larger circuit with multiple connections, whereas bilinguals recruited a smaller circuit that was more appropriate for the required information.

The participants did a task that required them to focus on visual information (the colour of an object) while ignoring spatial information (the position of the object).

The research team observed that the monolingual brain allocates a number of regions linked to visual and motor function and interference control, which are located in the frontal lobes. This means that the monolingual brain needs to recruit multiple brain regions to do the task.

"After years of daily practice managing interference between two languages, bilinguals become experts at selecting relevant information and ignoring information that can distract from a task," said Ana Ines Ansaldo from University of Montreal.
"Bilinguals showed higher connectivity between visual processing areas located at the back of the brain," Ansaldo said.

"This area is specialised in detecting the visual characteristics of objects and therefore is specialised in the task used in this study," she said.

"These data indicate that the bilingual brain is more efficient and economical, as it recruits fewer regions and only specialised regions," Ansaldo added.

Bilinguals have more centralised and specialised functional connections which saves resources compared to the multiple and more diverse brain areas allocated by monolinguals to accomplish the same task.

Bilinguals also achieve the same result by not using the brain's frontal regions, which are vulnerable to ageing.

This may explain why the brains of bilinguals are better equipped at staving off the signs of cognitive ageing or dementia.

The study was published in the Journal of Neurolinguistics.