Grant: Operating Grant

Symptomatic strokes cause paralysis or other neurological symptoms. However, it is now recognized that for every person with a symptomatic stroke there are up to 10 people who have unrecognized small strokes in the brain. These strokes contribute to the risk of dementia (the medical term for disabling problems with memory and thinking), which affects up to 25% of Canadians during their life. Up to half of dementia is caused by strokes or blood vessel diseases, and most of the rest is caused by Alzheimer's disease, another disease of the brain. Because we have no treatments to stop Alzheimer's disease, the most promising way to prevent dementia is to test treatments to prevent small unrecognized "covert" strokes. However we have very little information on how frequently new covert strokes occur. We also have very little information on what age covert strokes begin to occur at, because most previous studies have focused on the elderly exclusively without also including persons in middle-age. To address these limitations in our knowledge we are doing a study called PURE-MIND. Our objectives are to: a) find out how commonly covert strokes happen in mid-life, b) identify risk factors for covert strokes that might lead to new ideas for prevention beginning in middle age, before people get dementia in later life, and c) determine the consequences of covert stroke on the speed of thinking. This is a substudy of a large international study called PURE. The PURE-MIND substudy will enroll 1,500 Canadians age 40-70 who are participating in PURE. The study participants will have a brain MRI scan and cognitive tests. At the end of the study we will have information on how many people have had covert strokes, how it affects their memory, and what the risk factors are. We and others can use this information to plan subsequent studies to test treatments to improve memory and thinking by preventing covert strokes.