A clinical and autopsy study of dementia in Olmsted County, Minnesota, 1980-1981.

The clinical records and autopsy protocols were studied from 350 cases in which an autopsy was done in Olmsted County, MN, in 1980 and 1981. Overall autopsy rate was 33.6%, and autopsy rate for those aged 60 years or more was 29%. Preselected criteria were used for diagnosis of dementia. Thirty-two demented and 68 nondemented patients had complete autopsies; all were more than 60 years old. Twenty-three of 32 (72%) demented patients had Alzheimer's disease. The frequency of cerebral infarcts among the nondemented patients was significantly higher than among the demented patients (p = 0.02).