Exoskeleton Variability Optimization

Exoskeleton Variability Optimization for Reducing Gait Variability for Patients With Peripheral Artery Disease

The investigators will evaluate a potentially faster and more clinically feasible method to optimize exoskeletons in pilot tests in healthy in preparation for patients with peripheral artery disease.

Study Overview

• Status: Recruiting
• Conditions: Peripheral Arterial Disease
• Intervention / Treatment: Other: Endurance evaluation; Other: Exoskeleton optimization

Detailed Description

This study will test different methods for optimizing exoskeletons. It will consist of an habituation session to the hip exoskeleton, an optimization session to find the optimal actuation settings using an algorithm that converges toward the optimum based on real-time measurements (human-inthe-loop algorithm) and a post-test at the end of optimization session to compare different conditions. The outcomes will be evaluated by surface electromyography (Delsys), exoskeleton sensors (Futek), ground reaction force (Bertec treadmill), walking speed (Bertec treadmill), indirect calorimetry (Cosmed), and motion capture (Vicon).

• Study Type: Interventional
• Enrollment (Estimated): 22
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Philippe Malcolm, PhD; Phone Number: 617-487-1148; Email: pmalcolm@unomaha.edu

Study Locations

• United States
  • Nebraska
    • Omaha, Nebraska, United States, 68182
      • Recruiting
      • University of Nebraska Omaha
      • Contact: Philippe Malcolm, PhD; Phone Number: 402-554-4182; Email: pmalcolm@unomaha.edu
      • Principal Investigator: Philippe Malcolm, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 19 years to 85 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Ability to provide written consent
• Chronic claudication history
• Ankle-brachial index < 0.90 at rest
• Stable blood pressure, lipides, and diabetes for > 6 weeks
• Ability to walk on a treadmill for multiple five-minute spans.
• Ability to fit in exoskeleton: waist circumference 78 to 92 centimeters, thigh circumference 48 to 60 centimeters, minimal thigh length 28 centimeters.

Exclusion Criteria:

• Rest pain or tissue loss due to peripheral artery disease (Fontaine stage III and IV).
• Foot ulceration.
• Acute lower extremity event secondary to thromboembolic disease or acute trauma
• Walking capacity limited by diseases which are unrelated to peripheral artery disease such as:

Neurological disorders, musculoskeletal disorders (arthritis, scoliosis, stroke, spinal injury, etc.), a history of ankle instability, knee injury, diagnosed joint laxity, lower limb injury, surgery within the past 12 months, joint replacement, pulmonary disease or breathing disorders, cardiovascular disease, or vestibular disorder. This will be determined by verbal questioning from research personnel by verbally asking about conditions limiting their walking, whether subjects are taking medications for those conditions, and physicians' recommendations about limiting activity.

• Acute injury or pain in their lower extremity or current illness.
• Inability to follow visual cues due to blindness.
• Inability to follow auditory cues due to deafness.
• Women who are currently pregnant are excluded for safety reasons.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Optimal assistance pattern; An optimization algorithm will change the assistance pattern on the hip exoskeleton during walking sessions and the optimal assistance pattern will be determined when gait variability is minimized.	Other: Exoskeleton optimization; Participants will walk 10 times of 1 minute duration while an optimization algorithm changes the assistance profile of an exoskeleton.
Experimental: Effects on endurance; Determine effects on endurance of participants using ground reaction force (Bertec treadmill), walking speed (Bertec treadmill), indirect calorimetry (Cosmed), and motion capture (Vicon).	Other: Endurance evaluation; Participants will walk 2 times at a speed of 1 meter per second until the participant indicates claudication or a maximum duration of 6 minutes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time to convergence	We will determine when the estimated optimal exoskeleton settings vary less than 10%	10 minutes
Peak extension timing	Timing of peak extension moment of exoskeleton (% stride cycle)	20 seconds
Peak flexion timing	Timing of peak flexion moment of exoskeleton (% stride cycle)	20 seconds
Largest lyapunov exponent	Largest lyapunov exponent of lower limb kinematics	20 seconds

Collaborators and Investigators

• Sponsor: University of Nebraska
• Investigators: Principal Investigator: Philippe Malcolm, University of Nebraska

Study record dates

Study Major Dates

• Study Start (Actual): January 31, 2022
• Primary Completion (Estimated): September 1, 2024
• Study Completion (Estimated): September 1, 2024

Study Registration Dates

• First Submitted: April 3, 2020
• First Submitted That Met QC Criteria: April 7, 2020
• First Posted (Actual): April 8, 2020

Study Record Updates

• Last Update Posted (Actual): October 3, 2023
• Last Update Submitted That Met QC Criteria: September 29, 2023
• Last Verified: September 1, 2023

More Information

Terms related to this study

• Keywords: Exoskeleton
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Atherosclerosis; Peripheral Arterial Disease; Peripheral Vascular Diseases
• Other Study ID Numbers: 0376-19-FB

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: No