Languages are used to convey thoughts, identity, knowledge, and the way people see and understand the world.
Mastering more than one language provides a gateway to other cultures.
In a new study, researchers found that actively using them also brings neurological benefits and protects people from cognitive impairment associated with aging.
They concluded that speaking two languages on a regular basis—and have done so all one’s life—enhances cognitive reserve and delays symptoms linked to cognitive decline and dementia.
The research was conducted by a team from the Universitat Oberta de Catalunya (UOC) and Pompeu Fabra University (UPF).
The prevalence of dementia in countries where more than one language is spoken is 50% lower than in those regions where the population uses only one language to communicate.
Previous work had already found that the lifelong use of two or more languages could be a key factor in increasing cognitive reserve and delaying the onset of dementia, as well as offering advantages for memory and executive functions.
In the study, the team established a bilingualism gradient: from people who speak only one language but are passively exposed to another, to individuals who have excellent proficiency in both and use them indiscriminately on a day-to-day basis.
The researchers focused on the population of Barcelona, where the use of Catalan and Spanish is highly variable, with some predominantly Catalan-speaking neighborhoods and others where Spanish is the main language.
They recruited 63 healthy individuals, 135 patients with mild cognitive impairment such as memory loss, and 68 people with Alzheimer’s—the most prevalent type of dementia—in four hospitals in Barcelona and the metropolitan area.
They used a questionnaire to establish proficiency in Catalan and Spanish and ascertain each person’s degree of bilingualism.
They then correlated this degree with the age of neurological diagnosis and the onset of symptoms.
They found that people with a higher degree of bilingualism received a diagnosis of mild cognitive impairment later than those who were passive bilinguals.
Speaking two languages and regularly switching from one to the other can be a lifelong training for the brain.
According to the team, such linguistic gymnastics is related to other cognitive functions, such as executive control, which kicks in when people perform several actions at once, for example when we drive, to help people filter out relevant information.
The brain’s executive control system is related to the system used to control two languages: It has to switch between them, making the brain focus on one and then the other, to avoid one language intruding into the other when we speak.
The team says in the context of neurodegenerative diseases, this system could offset symptoms.
So when something is not functioning well due to the disease, thanks to the fact that it is bilingual, the brain has efficient alternative systems for resolving the problem.
In fact, active bilingualism is an important predictor of delay in the onset of symptoms of mild cognitive impairment—a preclinical phase of Alzheimer’s disease—because it contributes to cognitive reserve.
Now, researchers want to see whether bilingualism is also beneficial for other diseases, such as Parkinson’s and Huntington’s disease.
One author of the study is Marco Calabria, a professor at the UOC Faculty of Health Sciences.
The study is published in Neuropsychologia.
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