TPAD for Recovery of Standing After Severe SCI

The purpose of this study is to investigate how standing and sitting balance control is altered after spinal cord injury (SCI) and how a new type of robotic assistive device may be used to improve muscle function. This device is called the Tethered Pelvic Assist Device, or TPAD. The main aims are to: 1\. Examine muscle activation patterns generated during different types of standing in spinal cord injured individuals using robotic assistance or self-assistance for balance 2 and 3. Examine the effectiveness of robotic-assisted stand training in the improvement of posture control during different types of standing and sitting in spinal cord injured individuals. Participants will be placed into one of 5 groups based on a physical classification of their spinal cord injury: Group 1: * Individuals with SCI that can stand independently * Will receive TPAD training * Will undergo standing, posture, sitting, and stepping assessments * Participation in this group will last about six months Group 2: * Individuals with SCI that cannot stand independently * Will receive TPAD training * Will undergo standing, posture, sitting, and stepping assessments * Participation in this group will last about 6 months Group 3: * Individuals with SCI that can stand independently * Will undergo standing and posture assessments * Participation in this group will last about 2 weeks Group 4: * Individuals with SCI that cannot stand independently * Will undergo standing and posture assessments * Participation in this group will last about 2 weeks Group 5: * Individuals without a SCI * Will undergo standing, posture, and sitting assessments * Participation in this group will last about 2 weeks

The investigators will be testing a device called the Tethered Pelvic Assist Device or TPAD. The TPAD provides active control and support of the trunk, pelvis, and knees during training to improve the ability to stand. Also, the TPAD can be used to safely challenge participants during standing by providing controlled "pushes" or "perturbations" that must be corrected for in order to maintain proper posture and upright balance. This could be helpful for improving muscle function after spinal cord injury. Methodology: The Tethered Pelvic Assist Device (TPAD) is a light-weight cable-driven robotic stand trainer that (i) can provide assistance-as-needed by applying corrective forces on the trunk and pelvis in response to their movement outside a pre-programmed area, and (ii) can apply controlled forces on the trunk and pelvis to perturb them from their nominal configuration during standing. A total of 50 participants will be enrolled in this study; they will be broken into five groups with 10 participants in each. All participants will undergo a physical classification of their spinal cord injury to determine eligibility and which group they belong in. Group 1 will consist of individuals with SCI that can stand independently and will receive TPAD training and assessments, Group 2 will consist of individuals with SCI that cannot stand independently and will receive TPAD training and assessments, Group 3 will consist of individuals with SCI that can stand independently and will receive assessments only, Group 4 will consist of individuals with SCI that cannot stand independently and will receive assessments only, and Group 5 will consist of individuals without a SCI that will receive assessments only. Each individual will serve as their own control, to reduce variability. Motor patterns recorded from the SCI research participants will be also compared to those collected from individuals who do not have a SCI. All participants will undergo the Stable Standing Assessment and Postural Perturbation Assessment. Groups 1, 2, and 5 will additionally perform the Stable Sitting Assessment and Postural Perturbation Assessment in Sitting. Only Groups 1 and 2 will also perform the Neuromuscular Recovery Scale and attend training sessions with the TPAD system.