 P001- UNDERREPRESENTED ELDERS IN THE BRAIN HEALTH REGISTRY: US REPRESENTATIVENESS AND REGISTRY BEHAVIOR. M.T. Ashford1,2,*, J. Ei chenbaum1,2,3, T. Williams1,2,3, J. Fockler2,3, M. Camacho1,2, A. Ulbricht2,3, D. Flenniken1,2, D. Truran1,2, R.S. Mackin2,4, M.W. Weiner1,2,3, R.L. Nosheny2,4((1) Northern California Institute for Research and Education (NCIRE) — San Francisco (United States); (2) Department of Veterans Affairs Medical Center, Center for Imaging and Neurodegenerative Diseases — San Francisco (United States); (3) Department of Radiology and Biomedical Imaging, University of California — San Francisco, USA; (4) Department of Psychiatry, University of California San Francisco — San Francisco (United States))