1 Professor and Vice Chair of Research, Department of Orthopaedic Surgery; Professor, Department of Physical Medicine & Rehabilitation; Director, Vanderbilt Center for Musculoskeletal Research; and Director of Research, Osher Center for Integrative Health, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
2 Professor and Chair, Department of Physical Therapy; Director, Center for Neurorehabilitation, Boston University Sargent College of Health & Rehabilitation Sciences; Director, American Parkinson Disease Association National Rehabilitation Resource Center, Boston, Massachusetts, USA.