Bilingualism May Lead To Improved Stroke Outcomes

Bilingualism may be associated with better outcomes after stroke, according to research published in Stroke.

Suvarna Alladi, DM, neurology professor at Nizam’s Institute of Medical Sciences (NIMS) in Hyderabad, India and colleagues found that bilingual patients were more than twice as likely to have normal cognitive functions after a stroke, compared with patients who only spoke one language. This follows previous research that bilingualism may delay the onset of Alzheimer’s disease.

“People tend to think of Alzheimer’s as the only cause of dementia, but they need to know that stroke is also an important cause,” said Subhash Kaul, DM, senior investigator and developer of the stroke registry at NIMS, in a press release.

For this study, the researchers examined 608 patients from the NIMS stroke registry who all had an ischemic stroke, and studied whether bilingualism, defined in the study as speaking two or more languages, affected post-stroke cognitive impairment in the absence of dementia. To ensure that the results weren’t due to bilinguals living a healthier lifestyle, they also took into account smoking, high blood pressure, diabetes, and age.

They found that the percentage of patients with normal cognitive functions after a stroke was more than twice as high in bilinguals as in monolinguals: 40.5% of bilinguals had normal cognition after a stroke, compared with just 19.6% of monolinguals. They also found that fewer bilinguals had vascular dementia or vascular mild cognitive impairment post-stroke (49%), compared with 77.7% of monolinguals.

No differences were found between bilinguals and monolinguals in vascular risk factors or age at stroke onset, suggesting that bilinguals’ improved outcomes were not due to healthier lifestyles.

The only outcome not influenced by the number of languages spoken was aphasia, which was found in nearly equal amounts in both groups (10.5% in bilinguals vs. 11.8% in monolinguals). This suggests that bilingualism does not offer protection because of better linguistic functions, but because of improved executive functions acquired through a lifelong practice of language switching. This is also supported by post-stroke tests the researchers administered: bilinguals performed better on tests that measured attention and the ability to retrieve and organize information.

However, these results do not necessarily mean that monolingual people should learn another language to protect themselves. The study’s results may be due to the location of the study, Hyderabad, India, in which many languages are commonly spoken, including Telugu, Urdu, Hindi, and English.

“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.”

Instead, “our study suggests that intellectually stimulating activities pursued over time, from a young age or even starting in mid-life, can protect you from the damage brought on by a stroke,” said Dr. Kaul.

Reference

1. Alladi S, Bak TH, Mekala S, et al. Impact of Bilingualism on Cognitive Outcome After Stroke. Stroke. 2015; doi:10.1161/STROKEAHA.115.010418.