1. Department of Physical Medicine and Rehabilitation, the University of Texas Health Science Center at Houston, Houston, USA
2. Department of Physical Medicine and Rehabilitation, the University of Texas Health Science Center at Houston, USA
3. Department of Physical Therapy, University of Texas Medical Branch, USA
4. Department of Neurology, the University of Texas Health Science Center at, Houston, USA
5. Laboratory of Biomechatronics and Intelligent Robotics, Department of Mechanical and Aerospace Engineering, North Carolina State University, USA