Could being bilingual actually provide a protective effect for cognition after a stroke?
A recent study
was conducted to address this exact question. The data came from the stroke registry of the Nizam's Institute of Medical Sciences (NIMS) in Hyderabad, India. Lead by Dr. Suvarna Alladi, neurology professor at NIMS, the researchers examined 608 patients who all had an ischemic stroke, and asked whether bilingualism affected cognitive outcome post-stroke.
They found that 40.5% of bilinguals had normal cognition after a stroke, as compared to 19.6% of monolinguals, showing that bilingualism may be associated with some sort of protective neurologic effect. Bilingual patients also performed better in tests that measured post-stroke attention and function.
Interestingly, bilingualism did not seem to have an effect on aphasia – a common post-stroke disorder that affects speech and language. For both monolinguals and bilinguals, aphasia frequencies were between 10 and 12%.
Speaking two languages may be associated with having a healthier lifestyle, which could confound the health results. So researchers took into account lifestyle factors such as smoking, high blood pressure, diabetes, and age. They found no differences in age of stroke onset or other vascular risk factors, suggesting that the bilinguals’ better post-stroke outcome wasn’t tied to lifestyle choices.
These results are intriguing, as they add to a growing body of research showing that bilingualism is associated with slower cognitive aging and a later onset of dementia. However, the results by Dr. Alladi are by no means conclusive.
The study was conducted in Hyderabad, India, a city where it’s common to speak multiple languages, including Telugu, Urdu, Hindi, and English. Admittedly, it’s not an ideal location to study whether bilingualism can positively influence stroke outcome. Even the study’s lead author mentioned this caveat.
“Constantly switching languages is a daily reality for many residents of Hyderabad,” Dr. Alladi said in a press release. “The cognitive benefit may not be seen in places where the need to function in two or more languages isn't as extensive.”
Another key factor that the study did not control for is the severity of the stroke in the patients. The biological consequences of a stroke largely depend on the location and the severity of the attack. Without having controlled for these factors, it’s difficult to attribute the improved cognitive outcome post-stroke to just bilingualism alone.
Though not conclusive, the results of this study could be generalized to mean that intellectually stimulating activities improve cognitive functions. This, of course, is no huge secret, but it offers another reason why we should exercise the brain in addition to the body.
Additional Source: Nature