Bilingualism in Parkinson’s Disease (PD) – Does it Improve Cognition and Quality of Life?

“Learning another language is not only learning different words for the same things but learning another way to think about things.” – Flora Lewis.

This trailblazing American journalist was communicating what she believed to be the extensive benefits of bilingualism, a perspective shared by many – that speaking more than one language is not only a good life skill, but also expands one’s perspective and ability to think. 

It has long been believed that speaking more than one language on a regular basis may help boost brain function and possibly preserve the brain as it ages. Some studies have supported this idea, particularly for healthy adults. Studies of people living with neurodegenerative diseases and dementia, however, have shown more mixed results.

In an upcoming publication in “Journal of Clinical and Experimental Neuropsychology”, Dr. Keera Fishman et al describe an ONDRI study designed to help determine whether bilingualism¹ is associated with cognitive² advantages or better wellbeing in Parkinson’s disease (PD); or alternatively, whether the possible benefits of bilingualism are lost in someone living with PD.

To answer this question, researchers used data collected from ONDRI’s Foundational study, whereby 140 individuals with PD (21 of whom were classified as bilingual) completed measures of wellbeing, functional independence, and cognitive decline. Participants also completed neuropsychological tasks to examine different thinking skills, including executive functions, which measure one’s ability to switch back and forth between tasks, understand abstract relationships, and organize and execute tasks. Given that executive function impairments often appear early and are an important cognitive symptom of PD, ONDRI researchers were especially interested to determine if bilinguals would have better executive function than monolinguals.

These researchers found that bilingualism in PD was not associated with better cognitive performance or wellbeing.

Specifically:

• Bilinguals scored lower than monolinguals on tests of attention/working memory and language
• There were no differences between bilinguals and monolinguals on executive function, memory, or visuospatial skills
• There were no differences between bilinguals and monolinguals in their report of cognitive decline, functional independence, or quality of life

Overall, bilingualism did not present a benefit to any variables examined.

Why is this study important?

The results of this study may be counter-intuitive to some. Bilingualism is widely believed, at least amongst the public, to help build positive reserve in the brain; this reserve is believed to help stave off the impacts of age and neurodegeneration on cognitive ability. This study shows that this may not be the case for people living at the early stages of PD, where certain networks in the brain are likely to be working less efficiently and effectively in these individuals than in healthy adults.

Indeed, this is the first study to examine the relationships between bilingualism and cognition across five different neuropsychological domains³, and with wellbeing and functional measures, in people living with mild to moderate PD. Given the small sample size and diversity of language backgrounds in this sample, however, researchers are encouraged to explore these relationships in larger samples of individuals with PD and to evaluate whether these relationships may change over time. Importantly, understanding and appreciating the unique social and cultural experiences of individuals with PD and their families is also important, in order to enhance the delivery of culturally relevant and responsive care for people with diverse language skills.

Researcher