Grant: CIHR Fellowship

Growing evidence suggests that disease of the small vessels that supply blood to the brain can contribute to memory decline in later life, and possibly predispose the development of Alzheimer's disease. However, these links have been inconsistent in clinical studies, and how disease of the small vessels harms the brain is poorly understood. This study examines subjects with different amounts of small vessel disease in order to better understand its relationship with brain volume loss, termed "atrophy", and memory decline. We will use magnetic resonance imaging scans to measure the amount of small vessel disease and the amount of brain atrophy. We will use a battery of tests to assess memory and other aspects of cognitive performance. We will undertake this work in two groups of patients; 50 with Alzheimer's and 150 without Alzheimer's. Those in the Alzheimer's group were chosen to have either minimal or significant small vessel disease. Those in the non-Alzheimer's group have different amounts of small vessel disease, ranging from none visible on imaging to that which affects a large proportion of the brain. We hypothesize that small vessel disease will be related to atrophy of the brain's memory centres and to poorer memory performance. We will also assess whether certain genetic risk factors, assessed from blood samples, can compound the risk of brain atrophy and memory impairment associated with small vessel disease. This will help to determine if these genes are involved in the pathways that lead to brain damage due to small vessel disease. This work is relevant to the health of many Canadians, since those with small vessel disease, both with and without clinical Alzheimer's disease, are a fast-growing segment of our aging population. Knowledge arising from this study will provide important new insights into factors that determine vulnerability to this disease, and suggest new ways by which we may be able to slow or prevent memory decline.