1. Movement Science Group, School of Life Sciences, Oxford Brookes University; School of Population Sciences, University of Birmingham; Rivermead Research Group, Oxford Centre for Enablement;
2. Movement Science Group, School of Life Sciences, Oxford Brookes University; Rivermead Research Group, Oxford Centre for Enablement;
3. School of Population Sciences, University of Birmingham;
4. School of Health Sciences, University of Birmingham;
5. Movement Science Group, School of Life Sciences, Oxford Brookes University;
6. Oxford Centre for Enablement, Windmill Road, Oxford, OX3 7LD;
7. Department of Clinical Neurology, University of Oxford, Radcliffe Infirmary;
8. Department of Clinical Neurology, University of Oxford, Radcliffe Infirmary; and
9. Department of Mathematical Sciences, Oxford Brookes University, UK