Development of Optimal Sensory Feedback Strategies to Maximize Function After Tetraplegia

February 17, 2026 updated by: Emily Graczyk, Case Western Reserve University

Development of Optimal Sensory Feedback Strategies to Maximize Function After Tetraplegia: A Sub-study of the Reconnecting the Hand and Arm to the Brain (ReHAB) Clinical Trial

The goal of this clinical trial is to learn more about how stimulating the nerves involved in sensation (either in the limbs or in the brain) can be used to restore sensation in participants who have a spinal cord injury. Participants in this study will have already been enrolled in the "Reconnecting the Hand and Arm to the Brain (ReHAB)" study, and received small electrodes in a part of the brain that is involved in sensing touch and pressure in the hand. The ReHAB study participants will also have received electrodes around the nerves in their arm. In this clinical trial, participants will receive two types of electrical stimulation:

  • Intracortical microstimulation (ICMS) which involves sending small electrical pulses to the part of the brain that processes sensation.
  • Peripheral nerve stimulation (PNS) which involves sending small electrical pulses to the nerves in the arm that transmit sensations from the hand.

Researchers will try different patterns of stimulation for both ICMS and PNS and study how the participants perceive the sensations from the different stimulation patterns. The researchers will also study how combining ICMS and PNS affects the perceived sensations.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

The overall goal of this study is to compare the sensations that are perceived from intracortical microstimulation (ICMS) to those perceived from peripheral nerve stimulation (PNS), and also to perceived sensations from a combination of ICMS and PNS.

Preceding study

Participants for this study will be individuals with a high-level spinal cord injury who are already enrolled in the "Reconnecting the Hand and Arm to the Brain (ReHAB)" clinical trial (ID# NCT03898804). The ReHAB clinical trial involves receiving tiny electrode arrays in the brain and small electrodes around some of the nerves in the arm. The goal of the ReHAB clinical trial is to restore arm and hand movement and sensation in individuals with paralysis from a spinal cord injury.

Goals of this clinical trial

The purpose of the proposed study is to investigate the perception and functional impact of sensory neurostimulation in participants with tetraplegia. Investigators will develop and implement novel paradigms of ICMS applied to primary somatosensory cortex (S1) and PNS applied to upper extremity nerves through chronically-implanted cuff electrodes. Investigators will also develop and assess hybrid neurostimulation paradigms involving paired application of ICMS and PNS. For each paradigm, investigators will quantify the perceived sensation with classic psychophysical methods. Investigators will also implement the approach into closed-loop tasks in virtual reality controlled through decoded cortical signals recorded from intracortical microelectrode arrays. Finally, investigators will assess the impact of each stimulation paradigm on residual sensory function.

In Aim 1, investigators will develop a novel ICMS paradigm that attempts to reproduce both the temporal and spatial activation patterns that occur in S1 during normal touch. Investigators will compare this novel paradigm to other existing ICMS encoders. Investigators will assess the impact of each ICMS encoder on perceptual response, task performance in virtual reality (VR), and residual sensory function. In Aim 2, investigators will develop novel PNS paradigms and assess the efficacy of PNS for sensory feedback in people with tetraplegia for the first time. As in Aim 1, investigators will develop and compare several PNS encoders, including those that reproduce aspects of the peripheral response to normal touch and traditional linear encoders. We will assess the impact of each PNS encoder on perceptual response, task performance in VR, and residual sensory function. In Aim 3, we will develop hybrid neurostimulation paradigms that pair ICMS with PNS. We will assess the impact of stimulation encoder and stimulation amplitude on the perceived sensations generated by hybrid stimulation. We will then investigate the impact of PNS-ICMS timing delays within the hybrid neurostimulation paradigm on the perceptual response, functional impact, and impact on residual sensory function.

All participants will participate in all aims and will receive all stimulation approaches and perform all tasks and measures. All participants will serve as their own control for the planned statistical analyses. The study will generate tens of thousands of perceptual response data points, hundreds of functional task data points, and hundreds of thousands of intracortical recordings (for exploratory analyses).

Study Type

Interventional

Enrollment (Estimated)

3

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Emily Graczyk, Ph.D.
  • Phone Number: 216.368.5182
  • Email: elg46@case.edu

Study Locations

  • United States
    • Ohio
      • Cleveland, Ohio, United States, 44106
        • Recruiting
        • Case Western Reserve University
        • Principal Investigator:
          • Emily Graczyk, Ph.D.
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Enrolled in the ReHAB clinical trial and received ReHAB system components via implantation surgery.
  2. Willingness and availability to follow the study protocol.

Exclusion Criteria:

  1. Lack of function or operability of all implanted ReHAB system components
  2. Severe pain or other chronic medical condition that would prevent the participant from completing study-related activities

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Device Feasibility
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Intracortical microstimulation and peripheral nerve stimulation for people with tetraplegia
The purpose of the proposed study is to investigate the perception and functional impact of sensory neurostimulation in participants with tetraplegia. Investigators will develop and implement novel paradigms of intracortical microstimulation (ICMS) applied to primary somatosensory cortex (S1) and peripheral nerve stimulation (PNS) applied to upper extremity nerves through chronically-implanted cuff electrodes. Investigators will also develop and assess hybrid neurostimulation paradigms involving paired application of ICMS and PNS. For each paradigm, investigators will quantify the perceived sensation with classic psychophysical methods. Investigators will also implement the approach into closed-loop tasks in virtual reality controlled through decoded cortical signals recorded from intracortical microelectrode arrays. Finally, investigators will assess the impact of each stimulation paradigm on residual sensory function.
Device: Brain Computer Interface (BCI) - Functional Electrical Stimulation (FES) system
Participants with tetraplegia who have received intracortical arrays in the sensory cortex and peripheral nerve cuff electrodes will undergo a variety of stimulation paradigms to investigate the perception and functional impact of sensory neurostimulation.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Force matching success rate
Time Frame: From enrollment to around two years after enrollment
Percentage of force matching trials per block in which the target force was achieved before the time limit
From enrollment to around two years after enrollment
Object discrimination accuracy
Time Frame: From enrollment to around two years after enrollment
Percentage of trials per block in which the correct object was identified
From enrollment to around two years after enrollment
Discrimination threshold
Time Frame: From enrollment until around two years post-enrollment
Minimal change in stimulation that results in a reliably distinguishable change in perceived magnitude
From enrollment until around two years post-enrollment
Tactor detection threshold
Time Frame: From enrollment to around two years after enrollment
Minimal mechanical stimulus, delivered by a tactor that the participant can reliably perceive
From enrollment to around two years after enrollment

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Sensory dynamic range
Time Frame: From enrollment until around two years post-enrollment
Difference in minimum and maximum stimulation levels that elicit detectable, comfortable sensation
From enrollment until around two years post-enrollment
Projected field location
Time Frame: From enrollment until around two years post-enrollment
The position of the sensory percept reported on a hand/arm diagram
From enrollment until around two years post-enrollment
Sensation quality
Time Frame: From enrollment to around two years after enrollment
The participant's description of the quality of the sensation evoked by stimulation, reported as a selection of descriptor words
From enrollment to around two years after enrollment
Naturalness rating
Time Frame: From enrollment until around two years post-enrollment
The participant's rating of the perceived naturalness of the stimulus on an open-ended scale
From enrollment until around two years post-enrollment
Tactor discrimination threshold
Time Frame: From enrollment to around two years after enrollment
Minimal change in mechanical touch input that results in a reliably distinguishable change in perceived magnitude
From enrollment to around two years after enrollment
Force matching time to target
Time Frame: From enrollment to around two years after enrollment
The time elapsed from the go cue required for the participant to hit the force target
From enrollment to around two years after enrollment
Posture matching success rate
Time Frame: From enrollment to around two years after enrollment
Percentage of posture matching trials per block in which the target posture was achieved before the time limit
From enrollment to around two years after enrollment

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Case Western Reserve University

Collaborators

Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
University Hospitals Cleveland Medical Center
Cleveland Clinic Lerner Research Institute

Investigators

  • Principal Investigator: Emily Graczyk, Ph.D., Case Western Reserve University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 13, 2026

Primary Completion (Estimated)

September 1, 2030

Study Completion (Estimated)

September 1, 2030

Study Registration Dates

First Submitted

November 4, 2025

First Submitted That Met QC Criteria

November 5, 2025

First Posted (Actual)

November 6, 2025

Study Record Updates

Last Update Posted (Actual)

February 19, 2026

Last Update Submitted That Met QC Criteria

February 17, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • STUDY20190226
  • R01HD117313 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

IPD may be shared for publications.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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