Indian study shows that bilingualism preserves cognition, even if you can't read

USA Today reports on a new study in the journal Neurology in which Indian researchers assessed the associations between bilingualism and onset of dementia among 648 patients (391 bi/multilinguals) who were all diagnosed with dementia. Controlling for lots of things like literacy levels, immigration status, education, and gender, the researchers found that onset of dementia was delayed by approximately 5 years among bilinguals as compared with their monolingual counterparts. This study is not particularly novel, but it's interesting because: 1) it's coming out of India and not Canada; 2) it's a naturalistic, not a laboratory study; 3) it takes into account natural variations in the general population like literacy, immigration, etc.; 4) it's messy, with missing data and the like. The analyses are simple and the findings are basic but compelling. Using multiple languages in daily life requires greater cognitive attention and flexibility, resulting in greater mental stamina which delays onset of dementia. Cite for the actual study is: Alladi, S. Bak, T.H., Duggirala, V., Surampudi, B., Shailaja, M., Shhukla, A.K., Chaudhuri, J.R., & Kaul, S. (2013). Bilingualism delays age at onset of dementia, independent of education and immigration status. Neurology, 81, 1 - 7.