Can Multilingualism Combat Cognitive Decline?

 “Se habla Inglés” or its alternative-language equivalent is a sign rarely seen unless one walks into one of the ethnic neighborhoods that enrich a city. A whopping 1 in 5 Americans speak a second language - a statistic not reflected in our social infrastructure. Though the United States has no official language, English prevails around the country, with second language options offered only in cultural hotspots. Even the public education system is oriented to an English-speaking perspective; oftentimes students are not exposed to language classes until high school, well after children’s developmental period for language. Though more than three hundred languages are spoken in the U.S, all but one are generally disregarded, and speaking another language is viewed as a neat trick rather than an important life skill. Instead of aiming for uniformity, people should take pride in their unique languages and should be open to learning new ways to interact with their community. Promoting multilingualism not only supports communication and internationality but also benefits the aging brain by curbing the effects of Alzheimer’s Disease. 

Growing increasingly confused as the months pass and slowly losing your sense of self sounds nightmarish, but for many older adults, dementia is a cruel reality and leading cause of disability. Of those, Alzheimer’s Disease (AD) is responsible for two-thirds of all dementia cases, according to the  WHO . AD is characterized by the build-up of proteins that cause the breaking down of the brain’s tissue, leading to the death of neurons. Neurons form a web of connections, and without these, the brain loses its ability to process, store, and recall information, manifesting as the widely known symptoms of dementia like memory issues and confusion. The brain’s short-term storage unit- the hippocampus- is particularly vulnerable due to its ability to create new neurons, known as neurogenesis, well into adulthood. Abnormal neurogenesis can mark the beginning of hippocampal decay and is correlated with AD.  

So, how can studying French in elementary school hinder this outcome? 

A recent study conducted by Cambridge University examined how bilingualism affected three mechanisms protecting against neuron death: brain reserve, cognitive reserve, and brain maintenance. Brain reserve is a physical durability accumulated throughout life based on brain stimulation and biological environment, similar to how muscles strengthen with training and nutrition; it proportionally protects against degeneration. Cognitive reserve is the neuron’s ability to adapt and become more efficient to compensate for injury or aging. Lastly, brain maintenance describes a delay in brain changes related to age or the effects of a disease. The study compared participants of four groups: normal brain function, slight decline, mild impairment, and Alzheimer’s Disease; they hypothesized that bilinguals would display greater brain reserve in language-related areas of the brain and greater cognitive reserve in areas often affected by AD. Between monolingual and bilinguals, the study found no significant difference in the overall amount of grey matter in language regions; grey matter is a type of tissue in the nervous system full of neurons and essential to normal function. 

These results do not align with the researcher’s initial predictions, as they expected to record higher grey matter content in bilinguals, meaning a greater brain reserve. Cognitive reserve works in the opposite way, where less grey matter content (i.e., more decay) indicates a higher cognitive reserve because adapted neurons can reach the same standard of performance with less overall neurons. On this point, the researchers were again unable to find any distinction in decay between the two groups, indicating that cognitive reserve is unaffected by bilingualism. Although their data did not follow the study’s original purpose, comparative data notably showed that monolingual groups experienced increasing cell death in the hippocampus as the severity of AD progressed while bilinguals did not. Bilingual retention of their hippocampal volume can be interpreted as one of the three reserve mechanisms: brain maintenance. This region of the brain showed delayed changes in the face of disease, indicating that the structure of the hippocampus was more well maintained in bilinguals. 

While the study’s results were unable to support its hypothesis regarding brain and cognitive reserve, it distinctly mentions that nearly a third of the participants had learned their second language later in life and did not use it often. Here lies the issue, as the researchers speculated these factors to be a key cause of the lack of observed cognitive reserve. Passive language use is a familiar story in the U.S; many students pay just enough attention to pass their required language classes, and then quickly ditch the vocab list. However, how might our aging population differ if bilingualism was the norm? Answering that question requires a look at one of India’s southern municipalities. 

A field study examining the aging population of Jayanagar, South Bengaluru, yielded quite distinct results from its Western counterpart. With twenty-two official languages in India, bilingualism is regarded as a social norm, providing a unique population for researching language’s relationship to dementia. To ensure accuracy in defining bilinguals, the study only considered participants bilingual if they scored greater than 70% in more than one language on the language use questionnaire. Placing high benchmarks of language comprehension ensures that the participants who qualified as bilingual were active users of both languages. The resulting data showed a significantly lower prevalence of mild impairment and dementia in bilinguals than in monolinguals. Additionally, when comparing the cognitively unimpaired groups, older bilingual adults also showed increased cognitive functioning over monolinguals. Across the board, bilinguals had healthier aging brains; when maintained life-long, bilingualism provides protection against cognitive decline. The results reinforce the idea that holistic bilingualism provides the population with cognitive benefits that cannot be acquired from passive language learning alone. 

As the two contrasting studies show, perhaps the issue lies not in having taken a couple of high school language classes but rather putting them to good use. In the context of cognitive protection, second languages are useless if not exercised often enough for the benefits to develop. Earlier introduction to languages and a greater societal acceptance of multilingualism is essential if language is to be employed as a shield against cognitive decline. Especially in the melting pot that is the United States, promoting multiple languages will not only increase connections between people, but can serve their future according to the results of Venugopal’s study. Protecting our aging population begins long before any symptoms manifest and lies in fortifying the mind at its peak to provide the strongest shield against mental decline. The best defense undoubtedly includes multiple languages that can bolster brain maintenance. Offering language classes in elementary schools, hosting multicultural events in the community, and increasing signage in other languages are just some of many starting places for a greater acceptance of the diverse world of multilingualism.