Language is a powerful tool that everyone uses to communicate with others. As the world becomes smaller and families become more diverse, more and more people are becoming fluent in two or more languages. According to researchers from the University of Oberta de Catalunya (UOC) and Pompeu Fabra University (UPF), actively using more languages has neurological benefits and can protect individuals from cognitive impairment associated with aging.
Their recent publication in Neuropsychologia states that speaking two languages on a regular basis since young enhances cognitive reserve and delays the appearance of symptoms associated with cognitive decline and dementia. Cognitive reserve refers to the brain’s ability to improvise and find an alternative way to findings a solution. This concept originated in the late 1980s when researchers described individuals with no apparent symptoms of dementia but during their autopsy had brain changes consistent with advanced Alzheimer’s disease. These individuals did not show symptoms when they were living as they had a large enough cognitive reserve to offset the damage and continue functioning as usual.
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Researchers from the study stated that the prevalence of dementia in countries where more than one language is spoken is 50% lower than in countries where only one language is mainly used to communicate. Previous research within this field has found that the lifelong use of two or more languages could be a critical factor in increasing cognitive reserve and delaying the onset symptoms of dementia. This said, researchers aimed to discover a mechanism in which bilingualism contributes to cognitive reserve and whether there were differences in terms of the benefit gained from different degrees of bilingualism. In order to observe a mechanism researchers established a bilingualism gradient: from those who only speak one language but ae passively exposed to another, to those who have excellent proficiency in two languages and use them interchangeably daily. The study focused on the population of Barcelona, where the use of Catalan and Spanish is variable with some areas being predominantly Catalan-speaking and others being Spanish-speaking.
The study recruited 63 healthy individuals, 135 patients with mild cognitive impairment such as memory loss, and 68 people with Alzheimer’s disease. A questionnaire was used to establish proficiency in Catalan and Spanish and the level of people’s bilingualism. Researchers then correlated this degree with the age of neurological diagnosis and the onset symptoms. Participants were then asked to perform various cognition tasks, focusing primarily on goal-direct behavior (executive control). This was done to better understand the origin of cognitive advantage, as previous studies have suggested that this is the source of benefit. Results showed that people with a higher degree of bilingualism received a diagnosis of mild cognitive impairment later than those who were passive bilinguals. Researchers stated that the system used to control two languages is related to other cognitive functions such as, the executive function which is stimulated when one performs several actions at once e.g., driving. This system is stimulated as when one speaks two languages, they must switch between them making the brain focus on one then the other, to avoid one language a mix of the two. It is suggested that in terms of dementia and cognitive impairment, this system could offset symptoms by allowing the brain to have efficient alternative systems for resolving the problem. The study also found that active bilingualism is an important predictor of delay in the onset of symptoms of mild cognitive impairment (preclinical phase of Alzheimer’s disease).
Original Source: Calabria, M., et al. (2020). “Active bilingualism delays the onset of mild cognitive impairment.” Neuropsychologia 146: 107528.
Link Source: https://www.sciencedirect.com/science/article/abs/pii/S0028393220302013?via%3Dihub