1. Department of Neurology (JG, NA), The Warren Alpert Medical School of Brown University, Providence, RI; Brown University School of Public Health (SG); Department of Neurology (PG), Medical University of South Carolina, Charleston, SC; Departments of Neurology and Radiology (SA-L), University of Texas Southwestern Medical Center, Dallas, TX; The Warren Alpert Medical School of Brown University (KH), Providence, RI; and Department of Public Health Sciences (MJG), Medical University of South Carolina.