NEUROPATHOLOGY IN CONTROLS AND DEMENTED SUBJECTS FROM THE BALTIMORE LONGITUDINAL-STUDY OF AGING

To establish correlations among cognitive states and neuropathology, w e have examined 22 subjects (69-97 years of age) from the Baltimore Lo ngitudinal Study of Aging (BLSA), of whom 15 had normal and stable cog nitive performances and seven had dementia of variable severity. In th e majority of normal subjects, few or no beta-amyloid (A beta) deposit s or senile plaques (SP) were present in the neocortex, but neurofibri llary tangles (NFT) were consistently found in CA1 of hippocampus and layer II of entorhinal cortex. In two (15%) normal individuals, the de nsities of SP were consistent with the diagnosis of possible Alzheimer 's disease (AD). We speculate that these cases with normal cognitive s tates and abundant neocortical SP may represent preclinical AD. We con clude that the neocortex of a majority of cognitively intact individua ls can remain free of A beta deposits or SP, even into the tenth decad e of life.