[Alzheimer's disease: early diagnosis].

Alzheimers disease and the other forms of dementia are frequently ignored in the general population, particularly after 80 years. This under-diagnosis concerns approximately one of every two patients, and is particularly common in early-stage dementia, in which only one of every three patients is diagnosed. Under-diagnosis is due to patients and families not consulting, as well as to diagnosis procedures not being performed by the general practitioner to explore cognitive complaint. However, once they have been initiated, the diagnostic procedures are adequately performed, and over-diagnosis is uncommon.