Effects of Exercise Modes on Cognitive Function, Brain Plasticity and Neurobiological Markers in the Community Dwelling Elderly

Cognitive function declines with aging. The age-related cognitive decline not only decreases the independence of the elderly but also increases the need of care services. Studies have shown the positive relationship between physical activity or physical fitness and cognitive function. However, Cochrane database of systemic review and meta-analysis studies indicate that although aerobic exercise effectively improves cardiopulmonary fitness of the elderly, it does not improve the cognitive function of the elderly. It is known that activities that require attention and memory increase the cognition of individuals. However, it is unknown whether exercise with different cognitive load would differentially affect cognitive function of the elderly. In addition, the mechanisms mediating the exercise-induced cognitive changes are unclear. The purpose of this study is to investigate the effects of exercise modes (exercise with different cognitive load) on cognitive function, brain plasticity and neurobiological markers in the community dwelling elderly. In addition, the relationships between function and brain plasticity, and between brain plasticity and neurobiological markers will be examined. I propose to conduct a three years of randomized controlled trial to answer the research questions stated above. A total of 112 community dwelling elderly aged older than 65 years old will be recruited. Participants will be randomized into control (C) group, aerobic exercise with high cognitive load (HE) group and aerobic exercise with low cognitive load (LE) group after the baseline evaluation. Participants in C-group will be asked to maintain their sedentary lifestyle. Participants in the HE -group and LE -group will receive moderate intensity aerobic exercise training for 4 months. The exercise mode of LE -group is brisk walking on a treadmill while the exercise mode of HE -group is aerobic dance. Participants will receive 3 times of assessment (baseline, post-training and follow-up). The follow-up assessment will reveal the maintenance of the training effects. Outcome variables include cognitive function, physical function, the structure and function of brain and circulating neurotrophic factors brain-derived neurotrophic factor, vascular endothelial growth factor and insulin-like growth factor type I. Magnetic resonance imaging (MRI) and functional MRI will be used to examine the structural and functional brain changes with exercise. Neurobiological markers will be examined by enzyme-linked immunosorbent assays. A multivariate 2-way repeated measure ANOVA (time x group) will be used to examine the training effects. The relationships between function and brain plasticity, and between brain plasticity and neurobiological markers will be examined by Pearson's correlation coefficient. The significance level is set at 0.05 (2-tailed).The proposed study is important because it will unveil whether aerobic exercises that accompany with cognitive challenges improve the cognitive function in the community dwelling elderly more effectively than doing aerobic exercises alone. Furthermore, the findings about the mechanisms mediating the exercise-induced cognitive changes provide the foundation for the development of therapeutic strategies to maintain/improve cognitive function of the elderly.

Project ID:PC10408-1269
External Project ID:MOST104-2410-H182-026