The STROKDEM study is based on the 5-year prospective follow-up of a population of around 1,000 stroke patients without dementia. Patients are over 40 years old and without dementia, displaying an hemorrhagic or an ischemic stroke, with a sus-tentorial localization, and included 72h before the onset of symptoms. Biological samples and MRI are performed at 72h after stroke occurrence. Thereafter, patients are regularly (6 months, 12 months, 36 months, 60 months) examined for clinical and cognitive assessment with biological samples and MRI. Patients with dementia are compared to patients without stroke to identify the factors associated with dementia occurrence.