1. Department of Clinical Neurosciences University of Calgary Calgary Alberta Canada
2. Department of Community Health Sciences University of Calgary Calgary Alberta Canada
3. Multiple Sclerosis Center Swedish Neuroscience Institute Seattle Washington USA
4. Department of Neurology Rijnstate Hospital Arnhem The Netherlands
5. Department of Medicine, Neurology service Hôpital Maisonneuve‐Rosemont Montreal Quebec Canada
6. Département de neurosciences, Faculté de médecine Université de Montréal Montreal Quebec Canada
7. Department of Neurology, MS Center Amsterdam Amsterdam University Medical Centers Amsterdam The Netherlands
8. Department of Biostatistics University of Alabama at Birmingham Birmingham Alabama USA