[Alzheimer and Alzheimer's disease: the present enlighted by the past. An historical approach].

The history of Alzheimer's disease cannot be dissociated from that of the concept of dementia, as well as from the life and work of Alois Alzheimer. In his seminal paper, in 1907, Alzheimer thought to have shown a specific disease distinct from senile dementia. However, following the work of Fischer, Perusini, Kraepelin and Alzheimer himself, in 1911, the specificity of the pathological process with regard to that of senile dementia was questioned. Therefore, Alzheimer's disease was for long considered as related to senium praecox. Neuropathological then genetic data, mainly the description of monogenic forms, have demonstrated the reality of a specific pathological process involving the amyloid protein metabolism. Then, senile dementia became the most frequent form of Alzheimer's disease. However, Alzheimer's disease could hardly be considered as a natural entity and, particularly in the common forms, many points remained to be clarified such as the relationship between the amyloid process and that of aging, the significance of histopathological lesions and their relationship with the clinical symptoms. Beyond the description of the disease termed by his name, Alzheimer's work played a major role in the individualization of arteriosclerotic dementia from general palsy, and in the distinction between vascular and degenerative dementia. Moreover, he first described the histopathological lesions of Pick's disease.