1. Brain Injury Research Center, TIRR Memorial Hermann, Houston, TX, USA;
2. Spinal Cord Injury and Disability Research Center, TIRR Memorial Hermann, Houston, TX, USA;
3. Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX, USA;
4. Center for Wearable Exoskeletons, TIRR Memorial Hermann, Houston, TX, USA