Ankle Robot to Reduce Foot Drop in Stroke

Adaptive Ankle Robot Control System to Reduce Foot-drop in Chronic Stroke

Deficits in ankle control after stroke can lead to foot drop, resulting in inefficient, aberrant gait and an elevated falls risk. Using a novel ankle robot and newly invented adaptive control system, this study tests whether robotic-assisted treadmill training will improve gait and balance functions in chronic stroke survivors with foot drop impairment. It is hypothesized that, compared to treadmill training alone, integrating adaptive ankle robotics with treadmill training will reduce drop foot during independent overground walking, resulting in greater mobility, improved postural control, and reduced fall risk.

Study Overview

• Status: Completed
• Conditions: Stroke; Foot Drop
• Intervention / Treatment: Device: Treadmill plus anklebot; Behavioral: Treadmill only

Detailed Description

This proposal investigates a novel ankle robot (anklebot) adaptive control approach integrated with treadmill training to reduce foot drop and improve mobility function in chronic hemiparetic stroke survivors. Currently, stroke survivors with foot drop are trained to live with a cane or other assistive device, and often ankle foot orthotics (AFOs) for safety. Neither mediates task-practice or neuromotor recovery.

The investigators have developed an adaptive anklebot controller that detects gait cycle sub-events for precise timing of graded robotics assistance to enable deficit severity-adjusted ankle motor learning in the context of walking. The investigators' pilot findings show that 6 weeks treadmill training with anklebot (TMR) timed to assist swing phase dorsiflexion only is more effective than treadmill alone (TM) to improve free-walking swing dorsiflexion at foot strike, floor-walking speed, and the benefits are retained at 6 weeks post-training. Notably, swing-phase TMR training improved paretic leg push-off, and reduced center-of-pressure sway on standing balance, indicating potential benefits to other elements of gait and balance, beyond those robotically targeted toward foot drop.

This randomized study investigates the hypothesis that 6 weeks TMR is more effective to improve durably gait biomechanics, static, and dynamic balance, and mobility function in chronic stroke survivors with dorsiflexion deficits, compared to TM alone. Aims are to determine the compare effectiveness of 6 weeks TMR vs. TM alone on:

1. Independent gait function indexed by gait velocity, swing-phase DF (dorsiflexion), terminal stance push-off.
2. Balance function indexed by measures of postural sway (CoP), asymmetric loading in quiet standing, peak paretic A-P forces in non-paretic gait initiation, and standardized scales for balance and fall risk.
3. Long-term mobility outcomes, assessed by repeated measures of all key gait and balance outcomes at 6 weeks and 3 months after formal training cessation.

• Study Type: Interventional
• Enrollment (Actual): 45
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Maryland
    • Baltimore, Maryland, United States, 21201
      • Baltimore VA Medical Center VA Maryland Health Care System, Baltimore, MD

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:

• Ischemic or hemorrhagic stroke > 2 months prior in men or women
• Residual hemiparesis of the lower extremity that includes symptoms of foot drop
• Capable of ambulating on a treadmill with handrail support
• Already completed all conventional physical therapy
• Adequate language and cognitive function to provide informed consent and participate in testing and training

Exclusion Criteria:

• Cardiac history of:

  • Unstable angina
  • Recent (< 3 months) myocardial infarction
  • Congestive heart failure (NYHA category II or higher)
  • Hemodynamic valvular dysfunction
  • Hypertension that is a contraindication for a bout of treadmill training (>160/100 mmHg on two assessments)

• Medical history of:

  • Recent hospitalization (< 3 months) for any serious condition leading to significant bed-rest or reduction in mobility function
  • Symptomatic peripheral arterial occlusive disease
  • Orthopedic or chronic pain conditions restricting exercise
  • Pulmonary failure requiring oxygen
  • Uncompensated renal failure
  • Active cancer

• Neurological history and exam consistent with:

  • Dementia
  • Receptive or global aphasia that confounds testing and training, operationally defined as unable to follow 2-point commands
  • Non-stroke neurological disorder restricting exercise (e.g. Parkinson's Syndrome, myopathy)
  • Untreated major depression

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Treadmill+anklebot; This group will receive gait training on a treadmill while wearing the anklebot with the adaptive control system.	Device: Treadmill plus anklebot; This intervention employs the use of the adaptive anklebot control system to complement treadmill exercise training over a 6-week intervention period.; Other Names: TMR
Active Comparator: Treadmill only; This group will receive gait training on a treadmill, without use of the anklebot.	Behavioral: Treadmill only; This intervention employs the use of a treadmill for gait exercise training over a 6-week intervention period; Other Names: TM

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Gait Velocity During Self-selected Overground Walking	Gait velocity during self-selected overground walking measured in cm/sec	Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months after completion
Anterior-posterior Propulsion Forces of Paretic Side During Gait	Newtons: anterior-posterior force generated during push-off phase of the gait cycle	Change from baseline to: Post 6-weeks training, 6 weeks after completion, and 3 (or 6) months
Peak Dorsiflexion Angle During Swing Phase of Gait	Degrees; extent of ankle dorsiflexion to enable foot clearance	Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months after completion
Postural Sway Areas During Quiet Standing	cm^2; extent of postural deviations to assess static postural control	Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months
Ratio of Asymmetric Loading in Quiet Standing	Ratio of Newtons of force per each leg (paretic/nonparetic) while standing quietly	Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months
Peak Paretic Push Off Forces During Gait Initiation	Newtons; magnitude of forward ground reaction forces	Change from baseline to: Post 6-week training, 6 weeks after completion, and 3 (or 6) months

Collaborators and Investigators

• Sponsor: VA Office of Research and Development
• Investigators: Principal Investigator: Steven J Kittner, Baltimore VA Medical Center VA Maryland Health Care System, Baltimore, MD

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2015
• Primary Completion (Actual): April 1, 2019
• Study Completion (Actual): June 30, 2019

Study Registration Dates

• First Submitted: June 19, 2015
• First Submitted That Met QC Criteria: June 24, 2015
• First Posted (Estimate): June 29, 2015

Study Record Updates

• Last Update Posted (Actual): May 20, 2020
• Last Update Submitted That Met QC Criteria: May 8, 2020
• Last Verified: May 1, 2020

More Information

Terms related to this study

• Keywords: Rehabilitation; Gait; Robotics
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Neuromuscular Diseases; Mononeuropathies; Peripheral Nervous System Diseases; Stroke; Peroneal Neuropathies
• Other Study ID Numbers: N1699-R

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No