Ankle Exoskeleton for Stroke Gait Enhancement

NCT07179627 | Recruiting FDA Device

• 2 other identifiers: IRB2025-962R01HD113598-01
• Study Type: interventional
• Target: 15
• Locations: 1 country
• Sites: 1

Brief Summary

This work will focus on new algorithms for robotic ankle exoskeletons and testing these in human subject tests. Individuals who have previously had a stroke will walk while wearing a robotic exoskeleton on a specialized treadmill as well as during other movement tasks (e.g., overground, stairs, ramps). The study will compare the performance of the advanced algorithm with not using the device to determine the clinical benefit.

Conditions

Stroke

Outcome Measures

Primary Outcomes (3)

• Temporal Convolutional Network (TCN) model performance (Joint moment estimation accuracy)

  This outcome represents the error with which the deep learning model embedded into our ankle exoskeleton's microprocessor predicts ankle joint moments in stroke patients. Specifically, the coefficient of determination (R²) is computed between the predicted ankle joint moments and the ground truth measurements. Ground truth measurements are obtained from a laboratory-grade force plate system and inverse dynamics calculations. Ankle joint moment predictions are made at a frequency of 200 Hz and compared to the laboratory-measured values. For these measures, higher R² values (closer to 1.0) indicate better correlation between predicted and actual ankle joint moments. This metric provides a comprehensive assessment of the exoskeleton's ability to accurately estimate ankle joint moments in stroke patients during tasks, with improved outcomes representing better assistive capabilities for the user.

  1 year

• Metabolic cost for level ground walking

  Metabolic energy expenditure will be quantified using an indirect calorimetry system (Parvo Medics, UT) that measures oxygen consumption (VO₂) and carbon dioxide production (VCO₂) during experimental tasks. Measurements will be collected from each participant during a 5-minute baseline standing period followed by level ground walking trials under two conditions: without the exoskeleton, with the exoskeleton in a powered state. Metabolic cost will be calculated from respiratory gas exchange data (VO₂ and VCO₂) using Brockway equations \[1\] for energy expenditure. Comparisons between the two conditions will be conducted to assess the effectiveness of the exoskeleton with respect to metabolic cost. Energy expenditure (kilojoule/minute) = 16.58 VO₂ (Liters/minute) +4.51VCO₂ (Liters/minute) \[1\] Brockway, J. M. "Derivation of formulae used to calculate energy expenditure in man." Human nutrition. Clinical nutrition 41.6 (1987): 463-471.

  1 year

• Biological Joint Work

  Mechanical work performed by the lower limb joints will be quantified through biomechanical analysis of motion capture data. Joint moments and angular velocities will be derived through inverse dynamics and kinematics, respectively. Joint power, calculated as the product of joint moment and angular velocity, will be integrated with respect to time using trapezoidal integration to determine mechanical work. Positive and negative work will be calculated by separately integrating positive and negative joint powers, providing comprehensive quantification of joint energy generation and absorption at each joint during the movement tasks.

  1 year

Secondary Outcomes (12)

• Single limb stance time asymmetry (temporal)

  1 year

• Step length asymmetry (spatial)

  1 year

• Interlimb propulsion asymmetry (kinetic)

  1 year

• Trailing limb angle (kinematic)

  1 year

• Anterior ground reaction force

  1 year

Study Arms (1)

Ankle exoskeleton for stroke gait assistance

EXPERIMENTAL

This study will be conducted on a sample population of stroke subjects (single arm). Subjects will be tested with the powered ankle exoskeleton and baseline conditions.

Device: Ankle exoskeleton; Other: Baseline (no ankle exoskeleton)

Interventions

Ankle exoskeleton DEVICE

The ankle exoskeleton provides bilateral torque assistance at the ankle joints during common functional tasks such as level-ground walking, stair and ramp ascent, and other daily activities, thereby reducing the mechanical workload and supporting more effective community ambulation. In particular, the device is designed to address drop-foot on the paretic side by delivering bidirectional assistance, which helps improve toe clearance during swing as well as push-off during stance. As a wearable assistive device, assistance is applied only while the device is worn.

Also known as: Powered ankle exoskeleton

Ankle exoskeleton for stroke gait assistance

Baseline (no ankle exoskeleton) OTHER

The intervention will serve as a baseline where participants will be asked to perform the tasks without wearing an ankle exoskeleton.

Ankle exoskeleton for stroke gait assistance

Eligibility Criteria

• Age: 18 Years - 85 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Between 18-85 years of age
• Had a stroke at least 6 months prior to study involvement
• Are community dwelling, which means you do not live in an assisted living facility
• Are able to provide informed consent to participate in the study activities
• Can safely participate in the study activities (per self-report)
• Must have a Functional Ambulation Category (FAC) score of 3 or above, which means you can walk without the assistance of another person

You may not qualify if:

• Require a walker to walk independently
• Have a shuffling gait pattern overground
• Have a Functional Ambulation Category (FAC) score of 2 or lower, which means you require the assistance of another person in order to walk
• Have a significant secondary deficit beyond stroke (e.g. amputation, legal blindness or other severe impairment or condition) that in the opinion of the Principal Investigator (PI), would likely affect the study outcome or confound the results
• For exoskeleton-only studies, the exoskeleton device does not fit appropriately or safely, as determined by the research team during the fitting assessment.

Sponsors & Collaborators

• Georgia Institute of Technology: lead
• Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD): collaborator

Study Sites (1)

Georgia Institute of Technology

Atlanta, Georgia, 30332, United States

RECRUITING

MeSH Terms

Conditions

Stroke

Interventions

BaseLine dental cement

Condition Hierarchy (Ancestors)

Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Vascular Diseases; Cardiovascular Diseases

Study Officials

• Aaron Young, PhD

  Georgia Institute of Technology

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Aaron Young, PhD

CONTACT

404-385-5306; aaron.young@me.gatech.edu

Kinsey Herrin, MSPO, C/LPO

CONTACT

kinsey.herrin@gatech.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: The model used is a repeated measures single arm study

Study Record Dates

• First Submitted: September 11, 2025
• First Posted: September 18, 2025
• Study Start: February 9, 2026
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): December 1, 2028
• Last Updated: February 17, 2026

Record last verified: 2025-09

Locations

US (1)