1. Department of Public Health Sciences, Medical University of South Carolina, Charleston (L.F., S.D.Y.).
2. Stroke Division, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (L.R., A.S., V.L., M.S.).
3. National Institute of Neurological Disorders and Stroke, Bethesda, MD (R.A.C.).