1. Center for Visual and Neurocognitive Rehabilitation, Rehabilitation Research and Development, Atlanta VA Medical Center, Decatur, GA 30033, USA
2. Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
3. Exponent, Inc., Biomechanics Practice, Atlanta, GA 30326, USA
4. George W. Woodruff Department of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
5. Department of Bioengineering, Faculty of Engineering, Imperial College London, London SW7 2AZ, UK