Magnetic resonance (MR) imaging studies of the brain in five elderly patients with non-Alzheimer dementia were compared with those in two groups of nondemented control subjects. Group 1 included five subjects aged 59-66; group 2 included nine subjects aged 74-81. In all of the demented patients and in three of the subjects in the older control group, MR showed diffuse, patchy white-matter lesions. A rating scale was used to grade the severity of the changes. The results suggest a higher incidence of white-matter lesions in elderly patients with non-Alzheimer dementia and in cognitively normal elderly with advancing age.