1. Medical Research Council Centre for Neuromuscular Diseases; University College London Institute of Neurology; Queen Square London WC1N 3BG UK
2. Foot and ankle unit; Royal National Orthopedic Hospital; Stanmore UK
3. School of Rehabilitation Sciences; St George's University of London/Kingston University; London UK
4. Department of Neurology; IRCCS Foundation, Carlo Besta Neurological Institute; Milan Italy
5. Faculty of Health Sciences; University of Sydney & Children's Hospital at Westmead; Sydney New South Wales Australia
6. Department of Neurology; Cedars Sinai Medical Center; West Hollywood California USA
7. Department of Neurology; Hospital of the University of Pennsylvania; Philadelphia Pennsylvania USA
8. Department of Neurology; University of Rochester; Rochester New York
9. Orthopaedic and Spinal Surgery Unit; Great Ormond Street Hospital; London UK
10. Department of Orthopaedics; ASL; Imola Italy
11. Department of Ankle and Foot Surgery; IRCCS Galeazzi; Milan Italy
12. Department of Orthopaedic and Rehabilitation; University of Iowa Health Care; Iowa City Iowa USA
13. Department of Orthopaedics; University of Pennsylvania; Philadelphia Pennsylvania USA
14. Department of Orthopaedics; University of Rochester; Rochester New York USA
15. Department of Neurology; University of Iowa health Care, Iowa City; Iowa USA