This study focuses on individuals who have had a recent (within 6 weeks) stroke and have no known history of dementia. The purpose of the study is to learn more about the factors that make people more or less likely to develop dementia (decline in memory, thinking, and other mental abilities that significantly affects daily functioning) after having a stroke. The study aims to identify patients at risk for dementia after their stroke so that future treatments may be developed to improve outcomes in stroke patients. For this study, a stroke is defined as an ischemic stroke (blood clot in the brain), intracerebral hemorrhage (bleeding in the brain), or an aneurysmal subarachnoid hemorrhage (bleeding around the brain caused by an abnormal bulge in a blood vessel that bursts). Researchers will review participants’ medical records and collect blood samples, as well as conduct interviews, physical and neurological exams, and cognitive assessments.