Clinicopathologic Studies in Cognitively Healthy Aging and Alzheimer Disease

Abstract

IN 1993, some of us published in the ARCHIVES a clinicopathologic study of persons who had brain postmortem examination at or after 80 years of age.¹ Of the 42 subjects, 37 were diagnosed clinically as having dementia of the Alzheimer type (DAT). Only 1 of the 37 had a non-Alzheimer degenerative disease; 36 were confirmed to have Alzheimer disease (AD) by the criterion of abundant neocortical senile plaques (SPs). The brains of the 5 cognitively healthy control subjects were largely free of SPs. That publication addressed the many reports that there are lesser differences in brain neuropathologic markers of AD between groups of persons with AD and nondemented control individuals aged 80 years and older, as compared with the considerable differences between younger persons with AD and controls.^2-5 We concluded that "neocortical senile plaque densities differentiate very old Alzheimer's disease subjects from nondemented controls, but there is a need for more postmortem studies of old people demonstrated to be free of dementia."¹