1. Division of Rehabilitation Sciences, The University of Texas Medical Branch, Galveston, TX 77555, USA
2. Human Engineering Research Laboratories, VA Pittsburgh Healthcare System, 7180 Highland Drive, Bldg. 4, 2nd Floor, 151R1-HD, Pittsburgh, PA 15206, USA
3. Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA 15213, USA
4. Department of Rehabilitation Science and Technology, University of Pittsburgh, Pittsburgh, PA 15260, USA
5. Department of Health and Community Systems, University of Pittsburgh, Pittsburgh, PA 15261, USA