The Brain in Motion II Study: Study Protocol for a Randomized Controlled Trial of an Aerobic Exercise Intervention for Older Adults at Increased Risk of Dementia

Abstract

\n Background: There remains no effective intervention capable of reversing most cases of dementia. Current research is focused on prevention, by addressing risk factors that are shared between cardiovascular disease and dementia (e.g., hypertension) before the cognitive, functional, and behavioural symptoms of dementia manifest. A promising preventive treatment is exercise. This study describes the methods of a randomized controlled trial (RCT) that assesses the effects of aerobic exercise and behavioural support interventions in older adults at increased risk of dementia due to genetic and/or cardiovascular risk factors. The specific aims are to determine the effect of aerobic exercise on cognitive performance, explore the biological mechanisms that influence cognitive performance after exercise training, and determine if changes in cerebrovascular physiology and function persist one year after a 6-month aerobic exercise intervention followed by a 1-year behavioural support program (at 18 months).Methods: We will recruit 264 participants (aged 50-80 years) at elevated risk of dementia. Participants will be randomly allocated into one of four treatment arms: (1) aerobic exercise and health behaviour support, (2) aerobic exercise and no health behaviour support, (3) stretching-toning and health behaviour support, and (4) stretching-toning and no health behaviour support. The aerobic exercise intervention will consist of three supervised walking/jogging sessions per week for 6 months whereas the stretching-toning control intervention will consist of three supervised stretching-toning sessions per week also for 6 months. Following the exercise interventions, participants will receive either one year of ongoing telephone behavioural support or no telephone support. The primary outcome is cognition assessed through neuropsychological tests. Secondary outcomes include variety of cerebrovascular/physiological, neuroimaging, sleep, cognitive, other psychological variables and healthcare utilization. The outcome assessments will be conducted at baseline, after the 6-month intervention, and 1 year after the completion of the exercise intervention (at 18 months).Discussion: This study will address knowledge gaps regarding the underlying mechanisms of the pro-cognitive effects of exercise by examining potential mediating factors, including cerebrovascular/physiological, neuroimaging, sleep, and genetic factors that will provide novel biologic evidence on how aerobic exercise can prevent declines in cognition with aging.Trial Registration: ClinicalTrials.gov (NCT03035851, 30 January 2017).