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.
