Ankle Robotics After Stroke

Portable Ankle Robotics to Reverse Foot Drop After Stroke

The randomized study (in Phase II of the U44) compares the efficacy and durability of 9 weeks (18 sessions) of robot-assisted physical therapy (PTR) versus physical therapy (PT) alone on foot drop as assessed by gait biomechanics (ankle angle at initial contact, peak swing ankle angle, number of heel-first strikes - % total steps, gait velocity) and blinded clinician assessment (dorsiflexion active range of motion, ankle muscle strength, assistive device needs).

Study Overview

• Status: Recruiting
• Conditions: Stroke; Hemiparesis; Foot Drop
• Intervention / Treatment: Device: PTR Physical Therapy while wearing Robot group (Phase II); Other: Physical Therapy Only (Phase II); Device: Cross over group for Physical Therapy n Sub-Acute group. (Phase II); Device: Chronic Stroke Subjects to receive robotic gait training therapy.

Detailed Description

This proposal investigates a portable ankle robot (AMBLE) to be used during over-ground mobility training to reduce foot drop and improve walking function in hemiparetic (half-body, partially paralyzed stroke patients with foot drop (inability to properly lift and clear the foot during walking. About 30% of stroke survivors are left with permanent ankle weakness that impairs their mobility and increases fall-risk. Currently, stroke survivors with foot drop live with a cane or other assistive device, and often ankle-foot braces (AFOs) for safety. These assistive devices do not reverse or reduce the underlying neurological foot drop problem. Recognizing the crucial role of ankle function in walking and balance, and recognizing that the distal part of the lower extremity often suffers the greatest damage after a human stroke, the investigators have come up with a portable ankle robot as a tool for therapists to help shape recovery of walking.

The AMBLE, and its underlying control system, uses information about how patients are walking from one step to another to assist and shape foot lifting so as to help re- train walking recovery by a process that neuroscientists call motor learning. It is the combination of the partially paralyzed stroke survivor's movement efforts with timely assistance "only as needed" by the robot that investigators and others show is the key to movement recovery after stroke. Thus, the ankle robot is not a crutch, but a learning and measuring device that incrementally "gets out of the way" of the learner to facilitate human robot learning such that the human takes over more of the volitional learning.

The research team at University of Maryland has demonstrated in 4 prior studies using seated and treadmill based robot assisted training using a bulky laboratory robot programmed with a motor learning formula that can improve ankle motor control in both the early and chronic phases of stroke, and this can improve over-ground unassisted walking. A significant proportion of stroke survivors showed session by session recovery of volitional (not assisted by the robot) ankle lifting during walking across 6 weeks of three 30- 45 minute sessions of robot training while walking on a treadmill, even years after their stroke. In fact, it has been found that two weeks of 3 sessions per week ankle robotics training was the time profile for most motor learning recovery to reduce foot drop. This information has informed the design of the study described below.

Previous research was done using a bulky, heavy (~8 lbs), and expensive laboratory robot that only allowed seated or treadmill based training because it was tethered by wires. This greatly limits how it can be used by physical therapists, and is not appropriately configured for ease of use by physical therapists in practice. NextStep Robotics invented and built the ankle robots motor learning programs with a lot of input from physical therapists and other rehabilitation clinicians into a portable lightweight robot that can be used over-ground anywhere with blue tooth controls that also tell the therapist precisely how well the stroke survivors is learning, step by step. It is this new portable ankle robot that is configured for use in practice that investigators seek to test in studies with physical therapists using it fully integrated into their usual outpatient stroke mobility recovery training at University of Maryland Orthopedics and Rehabilitation Institute.

This U44 Award from the National Institute of Neurological Disorders and Stroke (NINDS) is not a typical single phase randomized clinical study, but consists of Phase I that completes commercial design of the robot the first year, followed by Phase II randomized clinical trial across years 2-4 of a finalized commercial version of the ankle robot.

Phase II (following completion of commercial design in Phase I) is a randomized (group assignment by chance), blinded (outcome testing done by technicians unaware of patient group assignment), two arm (2 groups) study that investigates the hypothesis that in subacute (6 weeks to 6 months) stroke subjects with foot drop, AMBLE integrated physical therapy (PTR) consisting of 18 training sessions over nine weeks is more effective than usual physical therapy (PT) to improve foot drop outcomes measured by movement analyses of walking, and by standardized clinical assessments of walking including specific foot drop outcomes as assessed by a certified PT clinician (blinded to treatment assignment), cross checked by blinded review of 2 other clinicians of films of the standardized mobility assessments to provide a consensus impartial judgement. Notably, this Phase II study focuses on sub-acute stroke recovery (6 weeks to 6 months) because it represents a therapeutic window into which conventional outpatient physical therapy is typically front-loaded to optimize outcomes. This phase of stroke rehabilitation is selected to test the AMBLE in real world settings when outpatient physical therapy typically occurs, using a treatment frequency and duration (18 physical therapy sessions across 9 weeks) that is representative of practice in Maryland and most of the United States. If wearing the AMBLE robot during physical therapy in this time-frame reduces foot drop and improves longer term outcomes measured 3 months after all robotics therapy has ended, then the investigators will apply for FDA approval for the first robotics device to actively treat foot drop after stroke.

• Study Type: Interventional
• Enrollment (Anticipated): 140
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Josh Rudnicki; Phone Number: 443-869-3518; Email: JRudnicki@som.umaryland.edu
• Study Contact Backup: Name: Richard Macko, MD

Study Locations

• United States
  • Maryland
    • Baltimore, Maryland, United States, 21207
      • Recruiting
      • University of Maryland Rehabilitation & Orthopaedic Institute
      • Contact: Josh Rudnicki; Phone Number: 443-869-3518; Email: JRudnicki@som.umaryland.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Ages 18 and older
• In the subacute phase of stroke recovery (>6 weeks to <6 months post-stroke) with residual hemiparesis of the lower extremity that includes symptoms of foot-drop. - or - In the chronic phase of stroke recovery (>6 months post-stroke) with residual hemiparesis of the lower extremity that includes symptoms of foot-drop.
• Clear indications of hemiparetic gait by clinical observation

Exclusion Criteria:

• Cardiac history of (a) unstable angina, (b) recent (less than 3 months) myocardial infarction, congestive heart failure (NYHA category II); (c) hemodynamically significant valvular dysfunction
• Hypertension that is a contraindication for routine physical therapy (greater than 160/100 on two assessments).
• Medical History: (a) recent hospitalization (less than 3 months) for severe medical disease, (b) symptomatic peripheral arterial occlusive disease, (c) orthopedic or chronic pain conditions that significantly alter gait function, (d) pulmonary or renal failure (e) active cancer
• History of non-stroke neuromuscular disorder restricting gait.
• Aphasia or cognitive functioning that confounds participation, defined as unable to follow 2 step commands or judgment of the medical officer or therapist.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: PTR (Physical Therapy while wearing Robot group) (Phase II); Subjects receive 18 one-hour PT training sessions over 9 weeks while wearing the robot initially parameterized to individual deficit severity. Subjects perform over-ground mobility tasks of increasing challenge with robotic assist, as needed. Training is generally divided into 3 phases based on individual ability to address gait deficits, postural transitions, physical demand and environmental terrain.	Device: PTR Physical Therapy while wearing Robot group (Phase II); Subjects receive 18 one-hour PT training sessions over 9 weeks while wearing the robot initially parameterized to individual deficit severity. Subjects perform over-ground mobility tasks of increasing challenge with robotic assist, as needed. Training is generally divided into 3 phases based on individual ability to address gait deficits, postural transitions, physical demand and environmental terrain.; Other Names: PTR
Active Comparator: PT (Physical Therapy Only) (Phase II); Subjects receive 18 one-hour PT training sessions over 9 weeks. Subjects perform over-ground mobility tasks of increasing challenge with therapist assist, as needed. Training is generally divided into 3 phases based on individual ability to address gait deficits, postural transitions, physical demand and environmental terrain.	Other: Physical Therapy Only (Phase II); Subjects receive 18 one-hour PT training sessions over 9 weeks. Subjects perform over-ground mobility tasks of increasing challenge with therapist assist, as needed. Training is generally divided into 3 phases based on individual ability to address gait deficits, postural transitions, physical demand and environmental terrain.; Other Names: PT
Experimental: X-PTR, Cross over group for Physical Therapy n Sub-Acute group.; Participants enrolled in the physical therapy only group will be given the option to re-enroll as a cross over participant to receive 18 one-hour PT training sessions over 9 weeks while wearing the robot initially parameterized to individual deficit severity. Subjects perform over-ground mobility tasks of increasing challenge with robotic assist, as needed. Training is generally divided into 3 phases based on individual ability to address gait deficits, postural transitions, physical demand and environmental terrain.	Device: Cross over group for Physical Therapy n Sub-Acute group. (Phase II); Participants enrolled in the physical therapy only group will be given the option to re-enroll as a cross over participant to receive 18 one-hour PT training sessions over 9 weeks while wearing the robot initially parameterized to individual deficit severity. Subjects perform over-ground mobility tasks of increasing challenge with robotic assist, as needed. Training is generally divided into 3 phases based on individual ability to address gait deficits, postural transitions, physical demand and environmental terrain.; Other Names: X-PTR
Experimental: C-PTR, Chronic Stroke Subjects to receive robotic gait training therapy.; Chronic stroke subjects receive 18 one-hour PT training sessions over 9 weeks while wearing the robot initially parameterized to individual deficit severity. Subjects perform over-ground mobility tasks of increasing challenge with robotic assist, as needed. Training is generally divided into 3 phases based on individual ability to address gait deficits, postural transitions, physical demand and environmental terrain.	Device: Chronic Stroke Subjects to receive robotic gait training therapy.; Chronic stroke subjects receive 18 one-hour PT training sessions over 9 weeks while wearing the robot initially parameterized to individual deficit severity. Subjects perform over-ground mobility tasks of increasing challenge with robotic assist, as needed. Training is generally divided into 3 phases based on individual ability to address gait deficits, postural transitions, physical demand and environmental terrain.; Other Names: C-PTR

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Angle at Initial Contact	Angle at initial contact averaged across each gait cycle for each subject at a given testing time point.	Change from Baseline at both 9 Weeks and at 21 Weeks
Swing Dorsiflexion	Peak swing dorsiflexion averaged across each gait cycle for each subject at a given testing time point.	Change from Baseline at both 9 Weeks and at 21 Weeks
Number of Heel-First Foot Strikes	Number of heel-first foot strikes for each subject at a given testing time point.	Change from Baseline at both 9 Weeks and at 21 Weeks
Gait Velocity	Average gait velocity (meters/second) for each subject at a given testing time point.	Change from Baseline at both 9 Weeks and at 21 Weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Active range of motion for Dorsiflexion	Active range of motion measured for dorsiflexion by blinded clinician.	Change from Baseline at both 9 Weeks and at 21 Weeks
Ankle Muscle Strength	Measurement of ankle strength by blinded clinician using the MMT (manual muscle testing)	Change from Baseline at both 9 Weeks and at 21 Weeks
Number of Participants Using Assistive Devices and Ankle Foot Orthoses	Number of Participants Using Assistive Devices and Ankle Foot Orthoses	Change from Baseline at both 9 Weeks and at 21 Weeks
Dynamic Gait Index	Assesses gait, balance, and fall risk; ranges from 0-24; higher score is better	Change from Baseline at both 9 Weeks and at 21 Weeks
Berg Balance Scale	A 14-item objective measure designed to assess static balance and fall risk; ranges from 0-56; higher score is better	Change from Baseline at both 9 Weeks and at 21 Weeks
Stroke Impact Scale	A self-report questionnaire that evaluates disability and health-related quality of life after stroke.	Change from Baseline at both 9 Weeks and at 21 Weeks
Activities-Specific Balance Confidence Scale	A self-report measure of balance confidence in performing various activities without losing balance; ranges from 0-1600; higher score is better	Change from Baseline at both 9 Weeks and at 21 Weeks
CES-D (Center for Epidemiological Studies-Depression)	The Center of Epidemiological Studies-Depression, a 20-item measure that asks to rate how often over the past week the patient experienced symptoms associated with depression; ranges from 0-60; high scores indicating greater depressive symptoms.	Change from Baseline at both 9 Weeks and at 21 Weeks
NIH Stroke Scale	Tool used to quantify the impairment caused by a stroke, composed of 11 items; ranges from 0-42; higher score indicates greater impairment.	Change from Baseline at both 9 Weeks and at 21 Weeks
Falls Efficacy Scale	A 16-item self-administered questionnaire designed to assess fear of falling; ranges 16-64; higher score indicates greater fear of falling.	Change from Baseline at both 9 Weeks and at 21 Weeks
Fatigue Assessment Scale	10-item scale evaluating symptoms of fatigue; ranges from 10-50; higher score indicates greater levels of fatigue.	Change from Baseline at both 9 Weeks and at 21 Weeks
Modified Ashworth Scale	Measures spasticity in patients; ranges from 0-4; higher score indicates more spasticity/rigidity.	Change from Baseline at both 9 Weeks and at 21 Weeks

Collaborators and Investigators

• Sponsor: NextStep Robotics Inc.
• Investigators: Study Director: Brad Hennessie, MHA, MBA, NextStep Robotics Inc.

Study record dates

Study Major Dates

• Study Start (Actual): August 20, 2020
• Primary Completion (Anticipated): February 28, 2025
• Study Completion (Anticipated): February 28, 2025

Study Registration Dates

• First Submitted: October 14, 2020
• First Submitted That Met QC Criteria: October 14, 2020
• First Posted (Actual): October 20, 2020

Study Record Updates

• Last Update Posted (Estimate): January 26, 2023
• Last Update Submitted That Met QC Criteria: January 24, 2023
• Last Verified: January 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Neurologic Manifestations; Neuromuscular Diseases; Mononeuropathies; Peripheral Nervous System Diseases; Stroke; Paresis; Peroneal Neuropathies
• Other Study ID Numbers: 1 U44 111076-01

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No