Do you speak multiple languages? If not, there some research suggesting that you may want to start. Research from the University of Edinburgh in the United Kingdom revealed that individuals who are bilingual tend to have delayed onsets of dementia. Dementia is regarded as a specific genre of brain disorders characterized by impairments in cognition, memory, and motivation.
In previous studies conducted in Canada among patients diagnosed with Alzheimer’s disease, results indicated that individuals who spoke multiple languages experienced delayed onset in symptoms. Early research indicated that the symptoms of neurodegenerative disorders often appeared 4-5 years later than individuals who only spoke one language. Researchers at the University of Edinburgh in the United Kingdom attempted to expand upon this research.
They also wanted to know whether the bilingualism was responsible for the delay of neurodegenerative disorders, or whether other potential confounding factors like immigration status may be responsible for the delay. He also wanted to know whether other forms of dementia (other than Alzheimer’s disease) experienced the same delays in onset as a result of being bilingual.
University of Edinburgh: Being Bilingual Delays Dementia Onset
Lead researcher Thomas Bak from the University of Edinburgh conducted a study to determine whether there was an association between being bilingual and dementia age of onset. To conduct the study, he joined forces with a neurologist from the NIMSH (Nizam’s Institute of Medical Sciences) in Hderabad, India. Bak was quoted as saying, “In India, bilingualism is part of everyday life.”
The researchers compared nearly 650 individuals who visited the NIMSH over the course of 6 years. Roughly half of the patients were considered bilingual. It was found that the bilingual individuals experienced an average of a 4.5 year delay in symptom onset compared to individuals who were monolingual. It should also be mentioned that the team of researchers took into account as many potential confounding factors as possible.
Study: Researchers examined case records of 648 total patients that were diagnosed with dementia. Of the total, 391 of these patients were considered bilingual. The researchers also examined the number of languages the individual spoke, their amount of education, their occupation, as well as other potential confounding variables.
Results: It was found that the 391 bilingual patients had significantly later onsets of dementia. On average, the study found that individuals with bilingual capabilities developed dementia nearly 5 years (4.5 years) after individuals who were monolingual (only spoke one language). Additionally researchers noticed significantly later ages of onset for bilingual individuals who developed Alzheimer’s disease, frontotemporal dementia, and vascular dementia.
- What about being trilingual? The researchers also noted that there appeared to be no additional benefit associated with speaking more than 2 languages. Therefore individuals who may be trilingual, quadrilingual, etc. aren’t able to derive benefit from each additional language.
- Ruling out confounds: It should also be mentioned that other factors such as: sex, occupation, environment (urban vs. rural), education, etc. were all accounted for as potential confounds. Results indicate that being bilingual delayed the dementia onset regardless of these other potential factors.
Conclusion: As of now, this is the largest study to date that has discovered dementia onset is delayed among bilingual individuals. It is also the first study to document delays across various different dementia subtypes. It is also the first study to show that even among illiterate individuals, being bilingual still delays onset of dementia. Therefore researchers were able to conclude that being bilingual, regardless of other factors, is capable of preserving cognition, memory, and attentional functions.
Speaking multiple languages delays dementia, not education
Many people have long believed that educational advancement was responsible for determining whether someone developed dementia. Logically, some individuals may believe that illiteracy and lack of educational advancement may be responsible for causing dementia. However, based on this new research, it seems as though the only major factor that delays dementia is being able to speak multiple languages.
Researcher Ellen Bialystok from York University in Toronto commented about the study: “Incredibly the number of years in delay of symptom onset they reported in the Indian sample is identical to our findings.” She was responsible for leading the original studies that were conducted in Toronto. The newer study was able to confirm her original findings and rule out other confounding factors.
Additionally the newer research was able to prove that speaking more than 2 languages (e.g. trilingualism) offers no additional benefit in delaying the onset of dementia. The original study in Toronto also only took a look at the specific Alzheimer’s disease subtype of dementia, whereas this newer work found that being bilingual delayed other subtypes including: frontotemporal and vascular dementia.
Theory: Why does being bilingual delay dementia?
Researchers don’t know the exact mechanism by which bilingualism is capable of delaying dementia onset. However, lead researcher Thomas Bak speculates that it may be a result of frequently “switching” between multiple languages and having to cognitively suppress one language while speaking another. He surmises that the “permanent switching and suppressing offers you constant brain training.”
His theory that switching between languages may explain why there’s no additional benefit derived from being trilingual or quadrilingual. It is the act of “switching” between multiple languages and knowing more than two languages provides no additional benefit in terms of dementia delay.
Future studies & why you should learn to speak a second language
Thomas Bak is attempting to expand upon his existing study by determining whether age of acquiring bilingual capabilities affects dementia onset. In other words, if a person starts speaking a new language at age 20 vs. age 40, would the person who is 20 derive greater benefit? He is attempting to take a look at this in his future work. Early results suggest that regardless of the age that we are capable of speaking multiple languages, we will be able to delay dementia onset.
Most people would agree that a delay by 4.5 years is highly significant. If there was ever an incentive to learn another language (regardless of your age), a dementia delay should be it. Among individuals that may be genetically susceptible or more prone to development of dementia, this should be required as part of general health. Although scientists are working on developing better treatments for dementia, prevention is always the best medicine.
- Source: http://www.neurology.org/content/81/22/1938