Vascular dementia corresponding to intellectual degradation significant enough to disrupt daily life, attributed to cerebral lesions of vascular origin. They are the second cause of dementia after Alzheimer's disease in the defeated countries. Their diagnosis is made difficult, on the one hand by the diversity of lesions potentially responsible for cognitive disorders and on the other hand by their frequent association with Alzheimer's disease. No treatment, other than preventive treatment, has been validated in vascular dementia. Several concepts have attempted or are attempting to characterize vascular dementias ("multiple infarct dementias", "vascular cognitive impairment", "vascular cognitive impairment").