Post-stroke Cognitive Impairment and Dementia

Inclusion criteria: * Patients:management at the acute phase (duration \< 30 days) of stroke visualized by imaging, age between 40 and 80 years, French-speaking, reliable informant, agreeing to participate in the study. * Controls: derived from the general population and consenting to participate in the study. Exclusion criteria: * Patients: mental retardation, illiteracy, known dementia, schizophrenia or psychosis or history of psychiatric illness requiring a stay for \> 2 days in a psychiatry unit, comorbidities affecting cognition, persistent disturbance of consciousness, contraindication to MRI. * Controls: illiteracy, deficit on MMSE (Mini-Mental State Examination), visual, auditory or motor deficit, history of brain disease or psychiatric illness (schizophrenia or other psychosis) or ongoing psychiatric illness (depression or other) currently requiring treatment or requiring a stay \> 2 days in psychiatry unit or anxiety requiring more than one medication at the present time, alcoholism, opiate or illicit drug use \< 3 months, ongoing antidepressant or antiepileptic treatment, recent anxiolytic or hypnotic treatment, general anaesthesia \< 3 months, history of heart surgery with cardiopulmonary bypass