The focus of the program project is on the behavioral and biomedical correlates of the clinical course of individuals with dementia of the Alzheimer disease (DAT) in comparison with the course of healthy aging with a focus in the distinction between healthy aging and very mild DAT. The psychometric core contributes to this effort by administering a battery of psychometric tests that assess memory (primary, secondary, and semantic)as well as visuospatial/visuoconstructive, mental control, speeded psychomotor, and language abilities. These tests are use to document the cognitive status of the research participants both at entry into the study and longitudinally as well as to support specific aims of the program projects. These include the interrelationship of behavioral (Core B), clinical (Core A), and neuropathological (Core C, Project 2) indices of Alzheimer's disease (AD). In connection with Project 1, we will provide information about normal psychological function in the oldest old as well as how to distinguish normal aging from very mild AD in very late life. Data from the Psychometric Core will be used in both Projects 3 and 4, which will focus the on the relation between specific behavioral deficits and their corresponding neuropathologic lesions. This work will address both fundamental questions of brain-behavior relations as well as the issue of individual differences in the loci of lesions/deficits in the earliest stages of AD.