A new study suggests that speaking at least two language may help delay the symptoms of dementia by five or six years compared to those who speak only one language.
A group of researchers from the University of Edinburgh, Scotland went to India to study bilingualism. Although their study is not the first to conclude that speaking at least two languages delays dementia, their work is the largest and the first to provide evidence that literacy has no direct link or influence in development of neurodegenerative disease.
"We know from other studies that mental activity has a certain protective effect. Bilingualism combines a lot of different mental activities. You have to switch sounds, concepts, grammatical structures, cultural concepts. It stimulates your brain all the time," said co-author Thomas Bak.
India was a perfect location to perform the research because many residents speak more than one language. People normally speak different languages at home, in school, or at work on a daily basis.
The researchers examined the medical data of 648 patients diagnosed with dementia in one of Hyderabad city clinics. More than half of them speak more than one language.
The researchers found that bilingual or multilingual patients who had an average age of 65.6 developed the mental disorder five years later than those who only spoke one language and had an average age of 61.1 years.
When the illiteracy factor was considered, the results were the same for those literate and illiterate groups: patients who were bilingual or multilingual had the symptoms of dementia six years later.
Differences were notable in the following neurodegenerative diseases: the Alzheimer's disease, vascular dementia which is linked to poor blood flow to the brain, and the frontotemporal dementia which is caused by degrading functions of the frontal or temporal lobes of the brain.
The study was published in the Nov. 6 issue of the online journal Neurology.
