[Gaetano Perusini (1879-1915): his contribution to the description of Alzheimer's disease].

In 1906 Perusini began his scientific career publishing three papers. These articles were important for the understanding of degenerative dementia. Perusini studied the difference between Senile and Presenile Dementia. Emil Kraepelin distinguished its two forms, but Perusini didn't take a clear position because of his early heroic death on the slopes of Mount Sabotino on December in 1915.