# Proprioceptive Sensorimotor Integration with Neural Interfaces for Hand Prostheses

> **NIH VA I01** · LOUIS STOKES CLEVELAND VA MEDICAL CENTER · 2022 · —

## Abstract

Current prosthetic options do not meet the needs of all Veterans with upper extremity limb loss. Chronically-
implanted neural interfaces have shown promise for providing intuitive control and somatosensory feedback to
prosthesis users. However, restoring proprioception, which is the sense of limb position and movement, via
neural stimulation remains largely unexplored. Proprioception is critical for informing and modulating motor
control in able-bodied individuals, and without it, prosthesis users must rely on visual feedback. The goal of this
study is to understand the perception of proprioception from peripheral nerve stimulation (PNS) and its
integration with prosthesis control. The central hypothesis is that sensorimotor integration will be best when
both the proprioceptive inputs and the prosthesis control scheme match the underlying neural representations
of sensorimotor processes in the extant body schema. Providing natural proprioception to Veterans with upper
limb loss is the next critical step in the advancement of upper limb prosthetics toward having a hand again.
 Six participants with unilateral trans-radial or trans-humeral limb loss will be implanted with chronic neural
and muscular interfaces. Composite Flat Interface Nerve Electrodes (C-FINEs) will be implanted around the
residual median, ulnar, and radial nerves in the upper arm. Three trans-radial participants will be implanted
with bipolar intramuscular electromyography (EMG) electrodes (IMs) in residual muscles in the forearm. Three
trans-humeral amputees will receive Targeted Muscle Reinnervation (TMR) surgery at the time of implant and
IMs will be placed in re-innervated muscles. Participants will attend laboratory testing sessions every 45 days
for two years to complete experiments for the three specific aims of the study.
 In Aim 1, proprioceptive percepts elicited by peripheral nerve stimulation will be characterized. PNS-elicited
perceived hand movements will be tracked through contralateral posture matching. Regression analyses will be
performed to determine the contribution of various stimulation parameters on the resulting perceived hand
kinematics. This information will be used to build a stimulation encoder to provide time-varying proprioceptive
information. Paired agonist-antagonist PNS strategies will also be developed. The discriminability of agonist-
only and paired agonist-antagonist strategies will be compared with psychometric tests.
 In Aim 2, the role of direct muscle activation from PNS on stimulation-elicited proprioceptive percepts will
be examined. A nerve block using lidocaine injection will be performed on trans-radial participants to
temporarily anesthetize the forearm muscles. Perceived movements and EMG activity will be compared before
and after motor block for various PNS stimuli. For trans-humeral participants who will receive TMR, muscle re-
innervation takes ~3 months. Proprioceptive percepts and EMG activity will be compared before and after...

## Key facts

- **NIH application ID:** 10317327
- **Project number:** 1I01RX003699-01A1
- **Recipient organization:** LOUIS STOKES CLEVELAND VA MEDICAL CENTER
- **Principal Investigator:** Emily L Graczyk
- **Activity code:** I01 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2022
- **Award amount:** —
- **Award type:** 1
- **Project period:** 2021-11-01 → 2025-10-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10317327

## Citation

> US National Institutes of Health, RePORTER application 10317327, Proprioceptive Sensorimotor Integration with Neural Interfaces for Hand Prostheses (1I01RX003699-01A1). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10317327. Licensed CC0.

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