1. Department of Neurological Surgery, University of California, San Francisco, California, USA.
2. Department of Neurosurgery, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
3. Departments of Neurology and Neurosciences, The Ohio State University, Columbus, Ohio, USA.
4. Belford Center for Spinal Cord Injury, The Ohio State University, Columbus, Ohio, USA.
5. San Francisco Veterans Affairs Healthcare System, San Francisco, California, USA.
6. Department of Physical Therapy, University of Alberta, Edmonton, Canada.
7. School of Public Health Sciences, University of Waterloo, Waterloo, Canada.