Can Being Bilingual Affect the Onset of Dementia?

Abstract

101 ISSN 1479-6708 10.2217/FNL.14.8 © 2014 Future Medicine Ltd Future Neurol. (2014) 9(2), 101–103 The dramatic increase in the proportion of elderly people in the world population has led to a growing importance of age-related diseases, in particular dementia. Importantly, this development is not confined to the western world. Dementia is recognized as a major health issue in India, China and many other countries across all continents. It has been described as a “public health priority” by the WHO [1] and became the topic of the last meeting of the G8 economic superpowers in London (UK) in December 2013. Given the rather limited success of the currently available drug therapies for dementia, much interest has been directed towards potential risk factors, but also towards potential protective factors against it. An influential concept in this respect is that of cognitive reserve, assuming that a better level of premorbid functioning may delay the onset or alleviate the manifestations of cognitive decline. Many studies have documented an association between physical, mental and social activity and better cognitive function in old age [2]. From scientific journals to popular press, broad claims have been made regarding ‘brain boosting’ effects of crossword puzzles, training programs or video games. However, one type of mental activity seems to generate more controversy than others: bilingualism. The research on the relationship between bilingualism and dementia started explicitly with the seminal observation by Bialystok et al. that bilinguals develop dementia 4 years later than monolinguals [3]; a finding later confirmed by another study from the same Toronto-based research group [4]. However, these findings do not come out of the blue, but are a logical extension of the emerging field of bilingualism and cognition research. Cognitive advantages of bilingualism have been detected in infants as young as 7 months [5] and have been extensively documented in children [6]. At the other end of the life spectrum, the number of languages spoken has been associated with cognitive function in a large study of healthy elderly [7]. The results of another Canadian study from Montreal paint a slightly more complex picture, with a bilingualism effect detectable in the immigrant group