1. Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
2. Division of Biostatistics, Washington University School of Medicine, St. Louis, MO, USA
3. VA Maryland Health Care System, Baltimore, MD, USA
4. VA Multiple Sclerosis Center of Excellence-East, Baltimore, MD, USA
5. Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, USA
6. Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL, USA
7. Department of Neurology, George Washington University School of Medicine, Washington, DC, USA
8. Neurology Section, VA North Texas Health Care System, Medical Service Dallas, VA Medical Center, 4500 South Lancaster Rd, Dallas, TX 75216, USA
9. Department of Neurology and Neurotherapeutics, The University of Texas Southwestern Medical Center, Dallas, TX, USA