Prevention of cognitive disorders and dementia is a major public health issue. Several studies have found a significant association between the existence of arterial hypertension and the onset of cognitive disorders and dementia (vascular or Alzheimer's disease) several years later. Arterial hypertension causes vascular changes that affect blood flow and brain metabolism. Cognitive disorders may be related to the presence of focal ischemic lesions (infarction, lacunae) and/or chronic white matter ischemia (leucoaraiosis) related to damage to the small cerebral arteries (arteriosclerosis). Recent work also suggests that cerebral hypoxia and endothelial function abnormalities lead to changes in the blood-brain barrier leading to an accumulation of β-amyloid protein in the brain and the formation of responsible amyloid plaques. of Alzheimer's disease. Few therapeutic trials have included cognitive assessment and/or diagnosis of dementia. They all raise some important criticisms: cognition is never the primary endpoint, follow-up is too short to study dementia; the evaluation of cognitive functions is very summary, the number of patients "lost to sight" is significant and the subjects at risk of developing dementia are in very low proportion.