# Spinal root stimulation for restoration of function in lower-limb amputees

> **NIH NIH UH3** · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · 2020 · $145,703

## Abstract

PROJECT SUMMARY
Recent advances in design and actuation have led to important improvements in prosthetic limbs. However, these devices
lack a means for providing direct sensory feedback, requiring users to infer information about limb state from pressure on
the residual limb. Lack of sensation limits their ability to control the prosthesis and leads to slow gait and increased risk of
falling. There is also evidence that lack of sensory feedback contributes to phantom limb pain (PLP), and that electrical
stimulation at the dorsal root ganglia (DRG) can reduce PLP. The primary objective of this study is to use commercially
available, FDA-cleared spinal cord stimulator (SCS) leads to test the effects of electrical stimulation of the DRG and dorsal
rootlets (DR) as a means of restoring naturalistic sensation (e.g. pressure, movement), reducing PLP, and improving gait
function in transtibial amputees. We will use stimulation to (1) produce sensations of pressure and joint movement, (2)
reduce PLP, (3) evoke patterns of muscle activity that mimic automatic responses that occur normally during standing and
walking, and (4) improve postural stability when standing and walking with a sensorized prosthesis.
Aim 1: Use stimulation of the DRG/DR to generate naturalistic sensations of pressure and joint movement, localized
to the amputated limb, and achieve a clinically relevant reduction in phantom limb pain
To provide intuitive feedback, evoked sensations should be perceived as originating in the amputated limb and should feel
naturalistic. A concomitant reduction in PLP may also have important effects on quality of life. We will perform detailed
psychophysical testing in which stimulation parameters are varied while study participants are asked to report information
about the evoked sensation (e.g. location, modality, naturalness) and the effects on PLP.
Aim 2: Characterize the motor responses in the intact and amputated limbs evoked by DRG/DR stimulation and
their relationship to stimulation parameters
Bilaterally coordinated reflexes play an important role when responding to unexpected perturbations like slips and trips.
Additionally, the transitions between phases of gait are largely mediated by reflexive responses to sensory input from the
legs. For a prosthesis to restore the full capabilities of the amputated limb during standing and walking, the ability to evoke
and precisely control these patterns of reflexive activity will be critical. We will record electromyogram (EMG) signals
from the limbs during standing and walking while varying stimulus patterns and quantify the relationships between
stimulation parameters and evoked reflexive responses. Understanding these relationships will aide in the programming of
stimulation patterns for functional prosthesis use.
Aim 3: Decrease postural sway and increase gait stability by providing sensory feedback via DRG/DR stimulation
To quantify the functional impact of sensory restoration on prosthetic limb usa...

## Key facts

- **NIH application ID:** 10197646
- **Project number:** 3UH3NS100541-02S2
- **Recipient organization:** UNIVERSITY OF PITTSBURGH AT PITTSBURGH
- **Principal Investigator:** LEE E FISHER
- **Activity code:** UH3 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $145,703
- **Award type:** 3
- **Project period:** 2020-07-01 → 2020-10-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10197646

## Citation

> US National Institutes of Health, RePORTER application 10197646, Spinal root stimulation for restoration of function in lower-limb amputees (3UH3NS100541-02S2). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10197646. Licensed CC0.

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