Neuropathological findings in patients with clinical diagnoses of probable Alzheimer's disease.

To assess prospectively the accuracy of standard antemortem clinical diagnostic criteria for Alzheimer's disease, post-mortem examinations were performed on 25 patients who had met DSM-III criteria for primary degenerative dementia and National Institute of Neurological and Communicative Disorders and Stroke criteria for probable Alzheimer's disease. Seventeen patients (68%) met neuropathological criteria for Alzheimer's disease. Two presenile-onset patients had diffuse neocortical senile plaques of insufficient number for definite Alzheimer's disease. Six patients had non-Alzheimer's disease diagnoses. Five of these six had presenile-onset dementia. These results suggest caution in the antemortem diagnosis of Alzheimer's disease in presenile-onset dementia.