Bilingualism as a protection against the onset of symptoms of dementia.

Bilingualism as a protection against the onset of symptoms of dementia. Bialystok E, Craik FI, Freedman M.Department of Psychology, York University, 4700 Keele Street, Toronto, Ontario,Canada M3J 1P3; Rotman Research Institute at Baycrest, Canada.
Neuropsychologia. 2007;45(2):459-64. Epub 2006 Nov 27.

This study examined the effect of lifelong bilingualism on maintaining cognitive functioning and delaying the onset of symptoms of dementia in old age. The sample was selected from the records of 228 patients referred to a Memory Clinic with cognitive complaints. The final sample consisted of 184 patients diagnosed with dementia, 51% of whom were bilingual. The bilinguals showed symptoms of dementia 4 years later than monolinguals, all other measures being equivalent. Additionally, the rate of decline in Mini-Mental State Examination (MMSE) scores over the 4 years subsequent to the diagnosis was the same for a subset of patients in the two groups, suggesting a shift in onset age with no change in rate of progression.
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