A recent extensive study on the relationship of bilingualism and dementia has provided further evidence and support to the belief that bilingual individuals show a delay in onset of dementia in old age.
Sue Hughes reports in the Medscape Neurology section;
' More evidence that speaking a second language may protect against dementia has come from a study conducted in India.
The study, published online November 6 in Neurology, was conducted by a team led by Suvarna Alladi, DM, from Nizam's Institute of Medical Sciences, Hyderabad, India.
"This study provides the strongest evidence yet that speaking more than 1 language delays the development of dementia," coauthor Thomas H. Bak, MD, from the University of Edinburgh, United Kingdom, commented to Medscape Medical News. "We can't say we have proven the effect, but this is the largest and most thorough study conducted on the subject in the most appropriate population. It would be extremely surprising if the results were not real."
He explained that 2 previous studies, both conducted in Toronto, Canada, have suggested that bilingualism might postpone dementia. However, most of the bilingual participants were immigrants with very different cultural backgrounds than members of the monolingual group, which introduced a high degree of confounding.
The study involved 648 patients with dementia diagnosed at a specialist clinic, 391 of whom were bilingual. The age at onset of first symptoms was compared between monolingual and bilingual groups.
Results showed that overall, bilingual patients developed dementia 4.5 years later than those who spoke only 1 language. The effect was consistent across the different types of dementia and was also independent of other potential confounding factors such as education, sex, occupation, and urban vs rural dwelling of participants.'
The fact that the new study was conducted in Hyderabad, India with a mostly bilingual population has been described as a stroke of genius. The majority Hindu population speaks Telugu, whereas the Muslim minority speaks Dakkhini. Besides these languages most Hyderabadis learn English and Hindi in school and use them in formal context. Hence it is likely for a Hyderabad resident to be fluent in 2-3 languages.
Barbara J. King reports in the NPR Science blog;
' The patients who contributed data to the study, then, are surrounded by multiple languages in everyday life, not primarily as a result of moving from one location to another. This turns out to be an important factor, as the authors explain:
"In contrast to previous studies, the bilingual group was drawn from the same environment as the monolingual one and the results were therefore free from the confounding effects of immigration. The bilingual effect on age at dementia onset was shown independently of other potential confounding factors, such as education, sex, occupation, cardiovascular risk factors, and urban vs rural dwelling, of subjects with dementia."
What exactly is it about the ability to speak in two languages that seems to provide this protective effect? Alladi and co-authors explain:
"The constant need in a bilingual person to selectively activate one language and suppress the other is thought to lead to a better development of executive functions and attentional tasks with cognitive advantages being best documented in attentional control, inhibition, and conflict resolution."
Intriguingly, when a patient speaks three (or more) languages, no extra benefits accrue neurologically. Speaking a single language beyond one's native tongue is enough to do the trick.'
Therefore not only should we try to learn more then one language whenever the opportunity arises, but we should also make an effort to make our children at least bilingual if not multilingual.
P.S:
New Study Shows Brain Benefits Of Bilingualism (Link to Full Article)More Evidence Bilingualism Delays Dementia ( Link to Full Article)
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