Abstract:

The 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.

Source: Ellen Bialystok, Fergus I.M. Craik and Morris Freedman, Bilingualism as a protection against the onset of symptoms of dementia, Neuropsychologia, Volume 45, Issue 2, 2007, Pages 459-464.

The researchers said the extra effort involved in using more than one language appeared to boost blood supply to the brain and ensure nerve connections remained healthy — two factors thought to help fight off dementia. Research has previously found that exercising the frontal lobes (the part of the brain which controls planning and other high-level functions) can help build up a cognitive reserve which staves off the onset of dementia. Previous research by Bialystok et.al., has suggested that bilinguals have an advantage over monolinguals in nonlinguistic task involving executive control. Two of the fundamental executive processes are selective attention and task management which are centered in the frontal cortex of the brain.

Bilinguals may also show improved performance in a divided attention paradigm compared to monolinguals

Dual Modality Monitoring in a Classification Task: The Effects of Aging and Bilingualism

Ellen Bialystok, York University and Fergus Craik, Rotman Research Institute

Abstract: Dual task paradigms in which two tasks must be performed simultaneously require cognitive control to allocate attention between the tasks. In general, older adults have more difficulty in these paradigms than younger adults as processing resources diminish and cognitive control over those processes decline. However, lifelong bilinguals have demonstrated enhanced cognitive control in a number of executive function tasks, an advantage that increases in older adults as the decline in these executive functions is less severe than it is for monolinguals. Therefore, it is possible that bilinguals also show improved performance in a divided attention paradigm compared to monolinguals and that this advantage increases with age. Monolingual and bilingual participants who were younger (22 years) or older (60 years) adults performed in a dual-task classification paradigm. Visually (primary task) and auditorily (secondary task) presented streams of information were classified into two categories. Younger bilinguals were less disrupted than monolinguals in the primary visual task when the secondary classification task did not require much attention; older bilinguals were less disrupted than monolinguals in all conditions. The results point to a benefit in allocating attention between competing tasks that comes from being bilingual and an increase in that benefit in older age.

Source: Canadian Society for Brain, Behaviour and Cognitive Science 15th Annual Meeting

Further Readings and References:

Bialystok et. al., Executive Control in a Modified Antisaccade Task: Effects of Aging and Bilingualism, J. of Exp. Psychology, 2006.

Bialystok et. al., Effect of bilingualism on cognitive control in the Simon task: evidence from MEG, NeuroImage 24, 2005.