1. Department of Neurology, Boston University, Boston, MA
2. Department of Neurology, University of Pennsylvania, Philadelphia, PA
3. Department of Emergency Medicine, Thomas Jefferson University, Philadelphia, PA
4. Center for Clinical Epidemiology & Biostatistics, University of Pennsylvania, Philadelphia, PA
5. Health Services and Outcomes Research Center for Outcome and Effectiveness Research and Education, University of Alabama at Birmingham, AL
6. Center of Excellence in Comparative Effectiveness Research for Eliminating Disparities/Minority Health & Health Disparities Research Center, University of Alabama at Birmingham, AL
7. Department of Epidemiology, University of Alabama at Birmingham, AL
8. Department of Neurology, University of Cincinnati, OH
9. Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, PA