Scott Haldeman, DC, MD, PhD,1 Linda Carroll, PhD,2 J. David Cassidy, DC, PhD, DrMedSc,3 Jon Schubert, CMA,4 and Ake Nygren, DDS, MD, DrMedSc5 1Department of Neurology, University of California, Irvine, CA; Department of Epidemiology, School of Public Health, University of California, Los Angeles, CA 2Department of Public Health Sciences, and Alberta Center for Injury Control and Research, School of Public Health, University of Alberta, Canada 3Department of Public Health Sciences, Faculty of Medicine, University of Toronto an Division of Health Outcomes and Research, Toronto Western Research Institute, University Health Network, Toronto, Canada 4CEO–SGI, Regina, Saskatchewan, Canada 5Department of Clinical Sciences, Danderyd Hospital, Division of Rehabilitation Medicine, Karolinska Institutet, Stockholm, Sweden