1 Centre for Outcomes Research and Evaluation, Research Institute of the McGill University Health Center, Montreal, Quebec, Canada.
2 Department of Pediatrics and Neurology & Neurosurgery, McGill University, Montreal, Quebec, Canada.
3 Division of Child Neurology, Reference Center for Neuromuscular Diseases, Department of Paediatrics, University Hospital Liege & University of Liege, Liege, Belgium.
4 Muscular Dystrophy UK Neuromuscular Centre, Department of Paediatrics, University of Oxford, Oxford, United Kingdom.