The STROKDEM study is based on the 5-year prospective follow-up of a population of 1100 stroke patients without dementia. At inclusion in the cohort, main antecedents and risk factors, previous treatment and lifestyle, initial severity and etiology are recorded. Biological samples (for standard ans specialized analyses) 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 Magnetic Resonance Imaging. Patients with dementia will be compared to patients without stroke to identify, by logistic regression analysis and Cox model, the factors associated with dementia occurrence.