Reducing Asymmetry During Gait Using the TPAD (Tethered Pelvic Assist Device) for Stroke Patients

OBJECTIVES: The purpose of this study is to evaluate the overall feasibility in terms of safety, treatment tolerance and adherence as well as preliminarily address how effective this treatment model using the TPAD and overground training would be to reduce load asymmetry on the treadmill and promote increased stance symmetry on the paretic limb during overground gait.PARTICIPANTS: A total of 12 individuals in the chronic (\>6 months) stages post stroke will be recruited from a voluntary stroke research database for participation. DESIGN: A non-randomized pilot study of feasibility will be used to establish the feasibility and preliminary efficacy of using the TPAD in combination with overground training to reduce load force asymmetry in this population. METHODS: Participants will undergo a series of three assessments within a one-week time frame prior to initiating intervention. Intervention using the TPAD and overground training will occur during week 2 over 5 consecutive visits (Mon-Fri). Participants will also complete short walks before and after the intervention with an instrumented system that records individual walking characteristics. Participants will return one-week after completing the intervention for a final test of walking and balance. Each study visit will be approximately 1-1.5 hours in duration, and total participation should be completed within three weeks. EXPECTED OUTCOMES: We anticipate this training paradigm will prove feasible and effective in reducing both load and stance asymmetry in a population of individuals with chronic stroke.

There are a number of common impairments resulting from stroke that contribute to motor deficits which affect gait, or walking ability. These manifest as decreased walking speed, and further, as stroke affects only one side of the body, there are resulting asymmetries in time, spatial and force parameters during walking. Robotic-based therapies have been used to increase walking speed and reduce asymmetry in a population of individuals after stroke, however these therapies have demonstrated results similar to that of non-robotic, or conventional training. This is possibly due to the control strategies used in robotic training, which strategies limit participant involvement and reduce learning effect. The Tethered Pelvic Assist Device (TPAD) is a robotic device that uses motorized tethers attached to a belt at the user's pelvis to guide the pelvis along a pre-set movement trajectory. These tethers can be configured in an infinite array of possibilities, and most recently have been used to facilitate a body weight shift onto the paretic limb in a population of individuals after stroke. Other robotic devices constrain the limb through the entire movement trajectory and constrict the participants ability to participate in motor planning and movement execution. The TPAD promotes weight shifting, but allows an individual to freely move the limb and to navigate leg movement and foot placement independently, without constraints. Further, if coupled with overground training to promote transfer of improvements to walking over ground, this device maybe useful at improving symmetry in individuals after stroke.

Eligibility Criteria:
Inclusion Criteria:

* Chronic (\>6 months) post stroke
* Single stroke event
* Montreal Cognitive Assessment (MoCA) score of \>22
* Independently ambulating in the home
* Use of a unilateral assistive device (e.g. cane)
* Marked asymmetry in stance phase (defined by a symmetry ratio \< 0.90)

Exclusion Criteria:

* History of multiple strokes
* History of other neurological disease
* Uncontrolled medical issues
* Muscle contractures of the lower limb limiting range of motion