Can bilingualism act as a safety net for patients with early stages of dementia?

People with some form of neurodegenerative disorder are growing every day. One of those neurodegenerative disorder is dementia. Dementia is a disorder which causes deterioration in cognitive functions such as thought, language, memory, the capacity to learn, judgement, orientation, and comprehension. There are three stages of dementia and the common symptoms of early stages of dementia include forgetfulness, losing track of time, and spacing out. Dementia may result due to a wide range of diseases, traumatic brain injuries, and other forms of injuries in general which could directly or indirectly cause damage to the brain. At current there are over 55 million people living with dementia around the world. Among the 55 million, more than 60% live in low- and middle-income countries. The rate of a new case arising every year is 10 million. This rate is expected to rise incredulously in the coming years owing to the fact that a useful and efficient treatment is yet to be found to cure dementia. The most common form of dementia is Alzheimer’s disease and it may contribute to 60% to 70% of the cases.  

In the review article, Early bilingualism, language attainment, and brain development, Berken et al examined previous data and knowledge of “optimal periods in language development, with particular attention to the attainment of native-like phonology”. The main objective of this review was to understand how the molding of brain structure and function takes place depending on when the second language experience takes place. They chose to make bilingualism the model to make sense of how early versus late experience affects brain organization. There may be differences in brain organization because development of the brain takes place early especially for language processing, that is why it becomes harder for an adult to learn a completely new language from scratch. The article stated that “When exposure occurs after the optimal periods for language acquisition are closing or have closed, neuroplasticity still occurs, allowing for L2 acquisition throughout the lifespan. However, the mechanisms for such neuroplasticity later in life are likely to be qualitatively and quantitatively different from those biologically programmed to begin and end in early childhood”. Berken et al concluded that when two languages are learned together from birth, brain function and structure seem to be most efficiently organized. If development of a second language expertise takes place later in life, the ability for neuroplastic change appears to be more constrained resulting in a different path for the proficient acquisition of a second language (Berken et al. 2016).  

In most people’s lives, language takes up the largest portion of time every day. We continuously use language in some form or the other without even realizing the neuroplasticity that takes place. The article Can bilingualism protect the brain even with early stages of dementia? talks about a study done by Ellen Bialystok who is a York University researcher in the Faculty of Health alongside her team which explored, tested, and put forth new evidence on the theory that bilingualism may have the ability to expand cognitive reserve thereby delaying when Alzheimer's disease symptoms begin to take place. Bialystok says that the idea behind the study is that “Imagine sandbags holding back the floodgates of a river. At some point the river is going to win”, "The cognitive reserve is holding back the flood and at the point that they were when they were diagnosed with mild cognitive impairment they already had substantial pathology but there was no evidence of it because they were able to function because of the cognitive reserve. When they can no longer do this, the floodgates get completely washed out, so they crash faster." The study took place over five years and included 158 patients who were diagnosed with mild cognitive impairments. Among these patients, those who were bilingual were models for high cognitive reserve whereas monolinguals were models for low cognitive reserve. The age, education and cognitive level were controlled for. The researchers visited the clinic every six months to check on the patients progress and what they found was that the conversion after initial diagnosis for bilinguals versus monolinguals were much different. It took 1.8 years for the mild symptoms to convert to Alzheimer’s disease in bilinguals, whereas for monolinguals it took 2.6 years. This difference backs up their hypothesis that there was more neuropathology in bilingual patients when they were initially diagnosed compared to monolinguals, but bilingual patients were able to withstand it and have the same level of cognitive function as their counterparts. These results are an addition to the compiling evidence regarding bilinguals having more resilience when dealing with neurodegenerative diseases compared to monolinguals since bilinguals acquire a higher functioning level due to their cognitive reserve and as a result, they can remain independent longer.  

Even though certain level of neuroplasticity takes place, it may all depend on when the second language is learned. Even though bilingualism cannot prevent the inevitable, acquiring this ability may well serve as a cognitive reserve to prolonging the time when dementia symptoms occur, but whether this applies to both early and late experience is an area that may potentially requires further investigation. If such is the case, it may be a useful tool to start investing time learning a new language earlier or even later in life because it may have qualitative health benefits such as becoming more resilient in dealing with neurodegeneration. However, there is always a downside to having an upper hand and, in this case, even though bilingualism might be able to allow the patients to withhold their cognitive function for longer even with higher neuropathology of dementia already set in place, once the reserve is overflowing, cognitive impairment usually takes place faster in bilingual patients because their conditions were more severe to begin with. Therefore, there needs to be additional research on what else can be done alongside bilingualism to withhold it’s benefits for a longer term.   

Works Cited: 

World Health Organization. “Dementia.” Who.int, World Health Organization: WHO, 2 Sept. 2021, https://www.who.int/news-room/fact-sheets/detail/dementia. 

Berken, Jonathan A., et al. “Early Bilingualism, Language Attainment, and Brain Development.” Neuropsychologia, vol. 98, Apr. 2017, pp. 220-227, 10.1016/j.neuropsychologia.2016.08.031.  

“Can Bilingualism Protect the Brain Even with Early Stages of Dementia? Researchers Find Bilingualism Provides the Brain with Greater Cognitive Reserve, Delaying Onset of Symptoms.” Science Daily, https://www.sciencedaily.com/releases/2020/02/200213132619.htm.