1. Neurology, Johns Hopkins Aramco Healthcare, Dhahran, Saudi Arabia
2. Center for Biostatistics, The Ohio State University Wexner Medical Center, Columbus, OH, USA
3. Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
4. Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
5. Neurology Clinical Research Institute, Massachusetts General Hospital, Boston, MA, USA