1 From the Departments of Environmental and Occupational Health Sciences, Neurology, and Health Services (G.M.F.), University of Washington, Seattle; and the Department of Neurology (N.A.B.), University of Pittsburgh School of Medicine, PA. meddir@uw.edu.
2 From the Departments of Environmental and Occupational Health Sciences, Neurology, and Health Services (G.M.F.), University of Washington, Seattle; and the Department of Neurology (N.A.B.), University of Pittsburgh School of Medicine, PA.