Neurostimulation Exosuit Augmented Training (NEAT) in the Clinic

Neurostimulation Exosuit Augmented Training (NEAT) in the Clinic Using a Wearable Propulsion Neuroprosthesis

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.

Inclusion Criteria:

• Age 18 - 80 years old
• History of stroke event occurring at least 6 months ago
• Observable gait deficits characteristic of post-stroke hemiparesis
• Independent ambulation for at least 30 meters (with an assistive device if needed but without a rigid brace for the ankle)
• Ankle dorsiflexion range of motion at least to neutral (i.e., 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)
• HIPAA authorization to allow communication with healthcare provider as needed during the study period
• Medical clearance by a physician

Exclusion Criteria:

• NIH Stroke Scale Question 1b score > 1 and Question 1c score > 0
• Inability to communicate with investigators
• Visual neglect or hemianopia
• History of cerebellar stroke
• Actively receiving physical therapy for walking
• More than 2 unexplained falls in the previous month
• Pressure ulcers or skin wounds located near human-device interface sites
• Pacemakers or similar electrical implants that could be affected by electrical stimulation
• Metal implants directly under the stimulation sites
• Skin allergy or other condition sensitive to the adhesive from transcutaneous neurostimulation electrode pads
• Other medical, orthopedic, and neurological conditions that prevent full participation in the research