1. From the State University of New York Downstate Medical Center/Kings County Hospital (P.C.), Brooklyn, NY; the Department of Neurology (B.L.C.), University of Pennsylvania, Philadelphia, PA; the Department of Emergency Medicine (N.L.), Hospital of the University of Pennsylvania, Philadelphia, PA; the Department of Emergency Medicine (F.S.S.), University of North Carolina, Durham, NC; and the Departments of Emergency Medicine and Health Policy (J.M.P.), George Washington University, Washington, DC.