Robotic Exosuit Augmented Locomotion (REAL)

Study Overview
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Brief Summary
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Previous studies of the exosuit technology have culminated in strong evidence for the gait-restorative effects of soft robotic exosuits for patients post-stroke by means of substitution for lost function. The present study builds on this work by suggesting that an exosuit's immediate gait-restorative effects can be leveraged during high intensity gait training to produce long-lasting gait restoration. Current gait training efforts are focused on either quality or intensity. They focus on gait quality often by reducing the training intensity to allow patients to achieve a more normal gait. In contrast, efforts focused on training intensity push participants without focusing on the quality of their movements. These intervention paradigms generally fail to substantially impact community mobility. In this study, the investigators posit that exosuits can uniquely enable an integration of these paradigms (ie, high intensity gait training that promotes quality of movements). For this protocol, exosuits developed in collaboration with an industry partner, ReWalk™ Robotics will be used. To evaluate the effects of REAL gait training, the investigators will use clinical measures of motor and gait function, locomotor mechanics and energetics, and physiologic measures that may infer on motor learning. The spectrum of behavioral and physiologic data that we will collect will enable us to understand more comprehensively the gait-restorative effects of REAL.

Detailed Description
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Weakness of the ankle plantarflexors after a stroke results in impaired forward propulsion during walking, which consequently impacts walking efficiency and speed - parameters that are necessary for community participation. Next-generation soft, wearable robots, known as soft robotic exosuits, were developed to assist paretic ankle dorsiflexion during its swing phase and paretic ankle plantarflexion during push off. Prior observational studies of the exosuit technology have culminated in strong evidence of immediate gait-restorative effects for patients post-stroke through improved forward propulsion, and faster and farther walking. The investigators posit that gait training using exosuits will leverage these immediate gait-restorative effects to facilitate gait training at higher intensities without compromising gait quality. This type of training will facilitate lasting rehabilitative effects that persist beyond the use of exosuit. Leveraging a systematic approach in the staging of pilot studies toward larger clinical trials, this clinical validation was initiated with a single-subject study design followed by a case series, which both provided early evidence for the potential of gait training with exosuits in restoring propulsion and speed. As a next step, the investigators seek to examine the efficacy of these interventions under more robust terms by implementing a randomized clinical trial (RCT). The primary aim of the current study seeks to understand the rehabilitative effects of a Robotic Exosuit Augmented Locomotion (REAL) gait training program relative to matched gait training without exosuits (Control) on walking and propulsion function after stroke. It is hypothesized that REAL training will result in clinically meaningful improvements in walking speed that are greater than the speed gains following Control training. Further, this study seeks to examine whether training-related changes in propulsion function following both interventions (REAL, Control) influence the training-induced effects on walking function. The investigators hypothesize that REAL training will result in substantial gains in walking function that are achieved through improved propulsion function, while Control training will have modest gains in walking function that are not related to changes in propulsion. A secondary aim of this study is to evaluate single day changes in neuromuscular control following both interventions (REAL, Control), as measured by muscle synergies and the dynamic motor control index. The investigators hypothesize that neuromuscular control will immediately improve during powered use of a soft-robotic exosuit (i.e., immediate) and exosuit-induced improvements in neuromuscular control will show continued improvement over a single session of REAL gait training (i.e., adaptation), and persisting improvement to unassisted walking after a single session of REAL gait training (i.e., retention). In contrast, the Control training will show no changes in neuromuscular control. An additional secondary aim is to identify neuromuscular predictors of training-related improvements in walking and propulsion function. It is hypothesized that positive relationships will be observed between single-day changes in neuromuscular control and training-induced improvements in walking and propulsion function after 12 sessions of gait training. Moreover, the investigators hypothesize that regardless of baseline walking speed, individuals with higher baseline neuromuscular control will have the greatest training-induced improvements in propulsion and walking function after 12 sessions of gait training. For this protocol, exosuits developed in collaboration with an industry partner (ReWalk™ Robotics) will be used. To examine the effects of REAL gait training, the investigators will use clinical measures of motor and gait function, locomotor mechanics, and physiologic measures that may infer on motor learning. The spectrum of behavioral and physiologic data that will be collected will enable a more comprehensive understanding of the gait-restorative effects of REAL. This study will be implemented by carrying out the following study visits: (1) Primary screen over the phone, (2) Clinical screen & fit, (3) Exposure, (4) Pre-training evaluations, (5) Training (12 sessions)(6) Post-training evaluation, and (7) Retention evaluation. Randomization to either REAL or Control will occur after Pre-training evaluation. A washout period up to 4 weeks will precede Retention evaluation.

Official Title
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Robotic Exosuit Augmented Locomotion (REAL) in the Clinic and Community

Conditions
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Stroke

Intervention / Treatment
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* Device: Soft exosuit
* Behavioral: Gait training without exosuits


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18 - 80 years old Stroke event occurred at least 6 months ago Observable gait deficits Gait speed equal to or less than 1 m/s Able to walk without the support of another person for at least 6 minutes (may use an assistive device as needed, but without use of an ankle foot orthosis or brace) Passive ankle dorsiflexion range of motion to neutral with the knee extended (i.e., able to achieve an angle of 90 degrees between the shank and the foot) Resting heart rate between 40 - 100 bpm, inclusive Resting blood pressure between 90/60 and 170/90 mmHg, inclusive Exclusion Criteria: Score of >1 on question 1b and >0 on question 1c on the NIH Stroke Scale Inability to communicate with investigators Neglect or hemianopia Actively receiving physical therapy for walking History of cerebellar strokes Known recurring or repeating strokes Unexplained dizziness in the last 6 months Pressure ulcers or skin wounds located at human-device interface sites Other medical, orthopedic, and neurological conditions that prevent full participation in the research

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Participants are randomly assigned to either intervention of (1) REAL, or (2) Control.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: REAL training<br>Robotic Exosuit Augmented Locomotion (REAL) refers to gait training with soft robotic exosuits, performed under a speed-based approach where participants are asked to walk at faster speeds in treadmill and overground environments. Cues and summary feedback emphasizing walking speed and forward propulsion are provided by the physical therapist to facilitate goal-directed walking practice. Training is progressively challenging based on environmental complexity and practice variability. REAL includes 12 training sessions, administered 2-3x/week. Each session includes 30 minutes of total walking time. | Device: Soft exosuit<br>* A soft exosuit is a textile-based wearable robot that is worn on the paretic ankle. Soft exosuits provide assistive torques through retraction of Bowden cables that connect distally to anchor points on front and back of the ankle, assisting with dorsiflexion during swing for foot clearance, and plantarflexion during late stance to assist with propulsion, respectively. Exosuit assistance is provided synchronously based on the wearer's gait, as detected by integrated inertial measurement units.<br>|
| Active Comparator: Control training<br>Control training refers to similarly structured gait training as with REAL, with the only exception of using soft robotic exosuits. Control training is performed under a speed-based approach where participants are asked to walk at faster speeds in treadmill and overground environments. Cues and summary feedback emphasizing walking speed and forward propulsion are provided by physical therapist to facilitate goal-directed walking practice. Training is progressively challenging based on environmental complexity and practice variability. Control training includes 12 training sessions, administered 2-3x/week. Each session includes 30 minutes of total walking time. | Behavioral: Gait training without exosuits<br>* Control intervention will implement gait training without exosuits. Other elements of intervention are similarly structured as with REAL, with the only exception of using exosuits.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 6-Minute Walk Test (6MWT) | This is test of long-distance walking function. The participant will be asked to cover as much distance as they safely can for 6 minutes, and total distance is the main metric from this test. This will be performed without wearing the soft exosuit (No Suit) regardless of intervention. | Baseline (Pre-training Evaluation) | 
| 6-Minute Walk Test (6MWT) | This is test of long-distance walking function. The participant will be asked to cover as much distance as they safely can for 6 minutes, and total distance is the main metric from this test. This will be performed without wearing the soft exosuit (No Suit) regardless of intervention. | Post-training Evaluation (up to 6 weeks) | 
| 6-Minute Walk Test (6MWT) | This is test of long-distance walking function. The participant will be asked to cover as much distance as they safely can for 6 minutes, and total distance is the main metric from this test. This will be performed without wearing the soft exosuit (No Suit) regardless of intervention. | Retention Evaluation (up to 4 weeks post-washout) | 
| 10-Meter Walk Test (10MWT) | This is a test of short-distance walking function. The participant will be asked to walk at comfortable walking speed (CWS) and maximum walking speed (MWS) on a ten-meter straight walkway. | Baseline (Pre-training Evaluation) | 
| 10-Meter Walk Test (10MWT) | This is a test of short-distance walking function. The participant will be asked to walk at comfortable walking speed (CWS) and maximum walking speed (MWS) on a ten-meter straight walkway. | Post-training Evaluation (up to 6 weeks) | 
| 10-Meter Walk Test (10MWT) | This is a test of short-distance walking function. The participant will be asked to walk at comfortable walking speed (CWS) and maximum walking speed (MWS) on a ten-meter straight walkway. | Retention Evaluation (up to 4 weeks post-washout) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Forward propulsion | Forward propulsion refers to anterior component of the ground reaction forces that correspond to push-off subtask of the gait cycle. | Baseline (Pre-training Evaluation) | 
| Forward propulsion | Forward propulsion refers to anterior component of the ground reaction forces that correspond to push-off subtask of the gait cycle. | Post-training Evaluation (up to 6 weeks) | 
| Forward propulsion | Forward propulsion refers to anterior component of the ground reaction forces that correspond to push-off subtask of the gait cycle. | Retention Evaluation (up to 4 weeks post-washout) | 
| Muscle Synergies | Muscle synergies refers to the coordinated co-activation of muscles during walking. Electromyography data will be collected bilaterally from up to 12 lower-limb muscles during treadmill walking with and without the exosuit. The number, timing, and composition of muscle synergies will be calculated using standard non-negative matrix factorization techniques. | Baseline (Pre-training Evaluation) | 
| Dynamic Motor Control Index | The dynamic motor control index is a continuous summary metric of muscle co-activations during walking. Electromyography data will be collected bilaterally from up to 12 lower-limb muscles during treadmill walking with and without the exosuit. Using non-negative matrix factorization, the variability accounted for by the one-muscle synergy solution is converted into a z-score centered around 100. A value of 100 indicates neuromuscular control similar to neuro-typical adults and each 10-point deviation represents a difference of one-standard deviation from neuro-typical adults. | Baseline (Pre-training Evaluation) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Exosuit, Soft Robotics, Wearable Robots, Gait Rehabilitation, Propulsion