The primary goal of this study is to understand the feasibility and rehabilitative effects of a Neurostimulation Exosuit Augmented Training (NEAT) program designed to provide high-intensity gait training in progressively challenging environments for individuals in the chronic phase of stroke recovery. The investigators will monitor feasibility of the training program and assess walking endurance and energy efficiency before and after the training to quantify effects of the training program on the recovery of walking function driven by improvements in forward propulsion and symmetry between limbs. Participants will complete pre-training and post-training evaluations alongside 12 gait training sessions across 4-5 weeks.
Functional electrical stimulation (FES) is commonly used to manage foot drop in people with post-stroke hemiparesis. Emerging use of FES applied to the paretic plantarflexors to facilitate push-off ability during walking has been limited to the treadmill and highly supervised laboratory-based settings. This novel neurostimulation exosuit (i.e., neuroprosthesis) enables overground gait training in environments of varying complexity by giving clinicians the ability to modulate neurostimulation timing and intensity delivered to the dorsiflexors for swing-phase foot clearance and to the plantarflexors for stance-phase plantarflexor forward propulsion. Combined with progressive, high-intensity, task-specific gait training, as has been performed previously with soft robotic exosuits developed by the same research group, this propulsion neuroprosthesis will leverage i) immediate gait assistance from the neurostimulation to facilitate high intensity training without sacrificing gait quality and ii) neurorestorative properties of FES to encourage the recovery motor function to affected muscles. The primary objective of this study seeks to understand the feasibility and rehabilitative effects of a Neurostimulation Exosuit Augmented Training (NEAT) program designed to provide high-intensity speed-driven gait training in progressively challenging environments. The investigators hypothesize that the NEAT program will safely provide a standard dose of gait rehabilitation training within a clinic setting and that the training will result in clinically meaningful gains in walking endurance and energy efficiency driven by improvements in forward propulsion and symmetry between limbs. Secondary objectives of this study seek to assess the effects of the NEAT program on neuromuscular control to the paretic plantarflexors (i.e., central drive). The investigators hypothesize that repeated training with neurostimulation to the dorsiflexors and plantarflexors will result in increased neuromuscular control to the paretic plantarflexors. The NEAT program will consist of 14 total study visits: i) Pre-training Evaluation, ii) NEAT Training (12 sessions, 2-3 times per week), iii) Post-training Evaluation. The neurostimulation exosuit used in this study was developed for investigational use only by investigators at the Boston University Neuromotor Recovery Laboratory, the Harvard University BioDesign Lab, and the Harvard University Move Lab.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DEVICE_FEASIBILITY
Masking
NONE
Enrollment
4
A neurostimulation exosuit (i.e., neuroprosthesis) is a textile-based device worn on the paretic lower limb. Neuroprostheses deliver functional electrical stimulation through non-invasive surface electrodes placed on the front and the back of the leg, providing swing-phase dorsiflexor assistance for foot clearance and stance-phase plantarflexor assistance for forward propulsion, respectively. Neurostimulation assistance is provided synchronously with the wearer's gait, based on inertial sensors in the shoes that measure the wearer's unique walking pattern.
Center for Neurorehabilitation
Boston, Massachusetts, United States
Neuromotor Recovery Laboratory
Boston, Massachusetts, United States
Six Minute Walk Test (6MWT) Distance
This is a clinical test of long-distance walking function. The participant walks as far as they can safely in 6 minutes. Total distance covered in 6 minutes is the primary outcome from this test. This test will be performed without a neuroprosthesis (unassisted) and with electrical stimulation assistance from a neuroprosthesis (assisted).
Time frame: Pre-training Evaluation (baseline)
Six Minute Walk Test (6MWT) Distance
This is a clinical test of long-distance walking function. The participant walks as far as they can safely in 6 minutes. Total distance covered in 6 minutes is the primary outcome from this test. This test will be performed without a neuroprosthesis (unassisted) and with electrical stimulation assistance from a neuroprosthesis (assisted).
Time frame: Post-training Evaluation (average of 5 weeks)
Six Minute Walk Test (6MWT) Speed
Walking speed is also monitored during the 6MWT at each reference length completed (e.g., 30-meter stretch before turning around). Speed is calculated as the reference length divided by the time it took to walk that distance in meters per second (m/s). This metric will be measured during the 6MWT performed without a neuroprosthesis (unassisted) and with electrical stimulation assistance from a neuroprosthesis (assisted).
Time frame: Pre-training Evaluation (baseline)
Six Minute Walk Test (6MWT) Speed
Walking speed is assessed during the 6MWT at each reference length completed (e.g., 30-meter stretch before turning around). Speed is calculated as the reference length divided by the time it took to walk that distance in meters per second (m/s). This metric is assessed during the 6MWT performed without a neuroprosthesis (unassisted) and with electrical stimulation assistance from a neuroprosthesis (assisted).
Time frame: Post-training Evaluation (average of 5 weeks)
Energy Expenditure
Energy expenditure assessed using indirect calorimetry (COSMED K5) and is calculated as the volume of oxygen inhaled normalized by bodyweight and distance (mL O2/kg/m). This metric will be measured during the 6MWT performed without a neuroprosthesis (unassisted) and with electrical stimulation assistance from a neuroprosthesis (assisted).
Time frame: Pre-training Evaluation (baseline)
Energy Expenditure
Energy expenditure assessed using indirect calorimetry (COSMED K5) and is calculated as the volume of oxygen inhaled normalized by bodyweight and distance (mL O2/kg/m). This metric will be measured during the 6MWT performed without a neuroprosthesis (unassisted) and with electrical stimulation assistance from a neuroprosthesis (assisted).
Time frame: Post-training Evaluation (average of 5 weeks)
Ten Meter Walk Test (10mWT) Speed
This is a clinical test of short-distance walking function. The participant walks at a comfortable walking speed (CWS) and fast walking speed (FWS) on a 10-meter straight walkway. The middle six meters are used to assess speed across 3 trials for CWS and 3 trials for FWS.
Time frame: Pre-training Evaluation (baseline)
Ten Meter Walk Test (10mWT) Speed
This is a clinical test of short-distance walking function. The participant walks at a comfortable walking speed (CWS) and fast walking speed (FWS) on a 10-meter straight walkway. The middle six meters are used to assess speed across 3 trials for CWS and 3 trials for FWS.
Time frame: Post-training Evaluation (average of 5 weeks)
Plantarflexor Central Drive
Central drive is a measure of voluntary control of a muscle. The participant uses their plantarflexors to push into a torque-sensing plate. Upon reaching the plateau of a maximum voluntary contraction (MVC), a burst of electrical stimulation is delivered using the burst superimposition technique to activate any remaining muscle fibers that are not activated volitionally, obtaining the maximum force-generating ability (MFGA). Central drive is calculated as the ratio of MVC to MFGA as a percentage (i.e., 100% central drive indicates full voluntary control of the muscle). Paretic plantarflexor central drive is assessed every 3-4 training days.
Time frame: Pre-training Evaluation (baseline)
Plantarflexor Central Drive
Central drive is a measure of voluntary control of a muscle. The participant uses their plantarflexors to push into a torque-sensing plate. Upon reaching the plateau of a maximum voluntary contraction (MVC), a burst of electrical stimulation is delivered using the burst superimposition technique to activate any remaining muscle fibers that are not activated volitionally, obtaining the maximum force-generating ability (MFGA). Central drive is calculated as the ratio of MVC to MFGA as a percentage (i.e., 100% central drive indicates full voluntary control of the muscle). Paretic plantarflexor central drive is assessed every 3-4 training days.
Time frame: Training Day 3
Plantarflexor Central Drive
Central drive is a measure of voluntary control of a muscle. The participant uses their plantarflexors to push into a torque-sensing plate. Upon reaching the plateau of a maximum voluntary contraction (MVC), a burst of electrical stimulation is delivered using the burst superimposition technique to activate any remaining muscle fibers that are not activated volitionally, obtaining the maximum force-generating ability (MFGA). Central drive is calculated as the ratio of MVC to MFGA as a percentage (i.e., 100% central drive indicates full voluntary control of the muscle). Paretic plantarflexor central drive is assessed every 3-4 training days.
Time frame: Training Day 6
Plantarflexor Central Drive
Central drive is a measure of voluntary control of a muscle. The participant uses their plantarflexors to push into a torque-sensing plate. Upon reaching the plateau of a maximum voluntary contraction (MVC), a burst of electrical stimulation is delivered using the burst superimposition technique to activate any remaining muscle fibers that are not activated volitionally, obtaining the maximum force-generating ability (MFGA). Central drive is calculated as the ratio of MVC to MFGA as a percentage (i.e., 100% central drive indicates full voluntary control of the muscle). Paretic plantarflexor central drive is assessed every 3-4 training days.
Time frame: Training Day 9
Plantarflexor Central Drive
Central drive is a measure of voluntary control of a muscle. The participant uses their plantarflexors to push into a torque-sensing plate. Upon reaching the plateau of a maximum voluntary contraction (MVC), a burst of electrical stimulation is delivered using the burst superimposition technique to activate any remaining muscle fibers that are not activated volitionally, obtaining the maximum force-generating ability (MFGA). Central drive is calculated as the ratio of MVC to MFGA as a percentage (i.e., 100% central drive indicates full voluntary control of the muscle). Paretic plantarflexor central drive is assessed every 3-4 training days.
Time frame: Post-training Evaluation (average of 5 weeks)
Gait Propulsion
Propulsion is the anterior component of the ground reaction force corresponding to the push-off subtask of walking that propels a forward into the next step. Gait propulsion is assessed during the 6MWT using floor-embedded forceplates.
Time frame: Pre-training Evaluation (baseline)
Gait Propulsion
Propulsion is the anterior component of the ground reaction force corresponding to the push-off subtask of walking that propels a forward into the next step. Gait propulsion is assessed during the 6MWT using floor-embedded forceplates.
Time frame: Post-training Evaluation (average of 5 weeks)
System Usability Scale (SUS)
This is a self-report measure of usability of a device. The assessment asks about complexity of the device, need for technical support, confidence in using the device, etc. Each of the 10 questions is rated from 1 (strongly disagree) to 5 (strongly agree) and scaled with a maximum score of 100.
Time frame: First Training Day (Day 1)
System Usability Scale (SUS)
This is a self-report measure of usability of a device. The assessment asks about complexity of the device, need for technical support, confidence in using the device, etc. Each of the 10 questions is rated from 1 (strongly disagree) to 5 (strongly agree) and scaled with a maximum score of 100.
Time frame: Mid-Training (Day 7)
System Usability Scale (SUS)
This is a self-report measure of usability of a device. The assessment asks about complexity of the device, need for technical support, confidence in using the device, etc. Each of the 10 questions is rated from 1 (strongly disagree) to 5 (strongly agree) and scaled with a maximum score of 100.
Time frame: Last Training Day (Day 12)
Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) - Modified
This is a self-report measure of satisfaction with an assistive device. The assessment asks about various aspects of the device, such as size, weight, comfort, etc. The questions are rated from 1 (not satisfied at all) to 5 (very satisfied). This measure has been modified by the investigators to assess only the 8 questions related to device characteristics (i.e., removed questions related to technology services).
Time frame: First Training Day (Day 1)
Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) - Modified
This is a self-report measure of satisfaction with an assistive device. The assessment asks about various aspects of the device, such as size, weight, comfort, etc. The questions are rated from 1 (not satisfied at all) to 5 (very satisfied). This measure has been modified by the investigators to assess only the 8 questions related to device characteristics (i.e., removed questions related to technology services).
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Time frame: Mid-Training (Day 7)
Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) - Modified
This is a self-report measure of satisfaction with an assistive device. The assessment asks about various aspects of the device, such as size, weight, comfort, etc. The questions are rated from 1 (not satisfied at all) to 5 (very satisfied). This measure has been modified by the investigators to assess only the 8 questions related to device characteristics (i.e., removed questions related to technology services).
Time frame: Last Training Day (Day 12)