Grant: Project Grant

Every year, over 100,000 Canadians survive a stroke only to face months or years of disability. Physical rehabilitation is their best hope for regaining lost abilities like walking, gripping objects, and living independently. But doctors face a surprisingly basic unanswered question: When is the best time to start rehabilitation? Starting therapy too early after a stroke may overwhelm the injured brain. Waiting too long may miss a critical window when the brain is most ready to rewire itself. Large clinical trials have produced contradictory results, and because we cannot see inside a patient's brain in real time during recovery, we still do not know what the brain is doing differently when therapy starts early versus late. Our team has developed an animal model that lets us answer this question directly. Using non-human primates that experience strokes similar to those in humans, we can scan the brain before the stroke occurs, track how brain networks change week by week during recovery, and examine brain tissue at the cellular level afterward. We recently discovered that higher-order cognitive networks-not motor areas-best predict recovery, changing how we understand the brain after stroke. In this new study, we will compare three groups of primates receiving rehabilitation at different times after stroke: one group begins early, one begins later, and one begins later but trains longer so it receives the same total amount of therapy as the early group. This lets us measure separately whether recovery depends on when therapy starts or how much is given. Both male and female animals are studied in equal numbers to detect any sex-based differences. This research will identify the best time to begin rehabilitation after stroke and reveal brain markers that could one day help doctors personalize therapy schedules for individual patients. The goal is simple: help more stroke survivors recover more fully, by getting the timing of their therapy right.