Ageing Deftly: How Lifestyle And Context Transform Neurocognitive Ageing

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The ratio of Canadians older than 60 is rising. By 2050, they will comprise 41% of Canada's population. With these increased numbers of seniors come many comorbid health issues, including Alzheimer's dementia (A.D.). While there has been progress towards drug therapies for A.D., the effectiveness of these approaches is limited. While the drug industry catches up, researchers must explore alternatives for maintaining cognitive function and resisting dementia, to mitigate rising mental and physical health care costs for the A.D. and improve patient and family members quality of life. There are two promising approaches for improving older adults' cognitive function without new drug therapies. First, long-term experiential factors can slow cognitive decline, increasing resistance to Alzheimer's symptoms, allowing extended periods of independence. Such patients may have A.D. pathology postmortem but never display signs. Protective factors contributing to cognitive reserve (C.R.) include exercise, education, and bilingualism. For example, bilinguals are diagnosed with dementia 4.5 years later than monolinguals, yet brain scans of bilingual and monolingual Alzheimer's patients matched for symptoms show higher atrophy in bilingual brains. Thus, bilinguals endure more profound neuropathology before Alzheimer's symptoms appear. Second, environmental/contextual factors dynamically shape cognition. These factors include momentary changes in alertness due to fatigue, caffeine, mood, and individual differences in circadian rhythms and testing time. Asking individuals to perform demanding executive function tasks at their circadian peak (optimal time of day) improves cognitive performance. By failing to account for these factors, researchers could introduce systematic bias: e.g., to maximize an apparent age effect, they might test all participants in the afternoon, which would benefit younger adults (18-35 Y) and penalize older adults (65-80 Y). My research pushes these approaches into new territory by showing that older adults doing a working memory task at their optimal time of day performed more like young adults and demonstrated, for the first time, that older adults recruited similar brain regions as younger adults. I will recruit 17 HQP (7 graduate and 10 undergraduate students) over 5 years to examine how contextual factors (time of day, caffeination, etc.) and lifelong experiential factors (exercise, bilingualism, education) collectively delay age-related cognitive decline across 2 major projects and 9 experiments. This research will generate new knowledge about how these factors interact to best predict older adults' cognitive wellness. Using behavioural and neuroimaging methods, I will examine older adults' cognitive control by studying the impact of contextual factors, cerebral lifestyle factors, lifestyle factors with a cardiovascular origin, to recommend ways of optimizing the cognitive potential of older adults across cultures and countries.