# Portable Ankle Robotics to Reverse Foot Drop After Stroke.

> **NIH NIH U44** · NEXTSTEP ROBOTICS, LLC · 2022 · $66,667

## Abstract

Overall Project Summary
This proposal finalizes the design of a portable ankle robot as a therapeutic device to reverse foot drop and
restore safe independent walking after stroke, then conducts a rigorous randomized clinical trial to establish
clinical efficacy for this new market application. Product development is inspired by our five positive clinical
studies that demonstrate that ankle robot-mediated functional motor learning is most effectively conducted in
the context of locomotor task-oriented training. In Phase I, we pursued finalization of a lighter weight, battery
powered, and wirelessly controlled ankle robot (AMBLE) that meets basic clinical usability standards for regular
mobility-focused physical therapy (PT). Specific Phase I accomplishments include designing and bench testing
a functional beta prototype that meets key safety, stability, and comfort metrics during over-ground walking and
mobility tasks for full integration into PT. Phase II (3-yrs) is a blinded, randomized clinical trial investigating the
hypothesis that 9 weeks (18 sessions) of PTR is more effective than PT alone to reverse foot drop as
assessed by instrumented gait biomechanics and blinded clinician assessment. Our results will establish safety
and initial efficacy for reversal of foot drop as a new market application filling an unmet need, and shift care
toward PT-integrated robotic exoskeletons across other impaired joints.

## Key facts

- **NIH application ID:** 10657017
- **Project number:** 3U44NS111076-02S1
- **Recipient organization:** NEXTSTEP ROBOTICS, LLC
- **Principal Investigator:** Bradley Hennessie
- **Activity code:** U44 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $66,667
- **Award type:** 3
- **Project period:** 2021-05-01 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10657017

## Citation

> US National Institutes of Health, RePORTER application 10657017, Portable Ankle Robotics to Reverse Foot Drop After Stroke. (3U44NS111076-02S1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10657017. Licensed CC0.

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