Proprioceptive Sensorimotor Integration With Neural Interfaces for Hand Prostheses

Upper Limb Amputees Clinical Trial

— PSI  

Official title:

Proprioceptive Sensorimotor Integration With Neural Interfaces for Hand Prostheses

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT04947462
• Other study ID #: A3699-R
• Secondary ID: RX003699-0116247
• Status: Recruiting
• Phase: N/A
• Start date: December 1, 2021
• Est. completion date: December 31, 2025

Study information

• Verified date: January 2024
• Source: VA Office of Research and Development
• Contact: Emily L Graczyk, PhD
• Phone: (216) 791-3800
• Email: Emily.Graczyk[@]va.gov
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The purpose of this study is to characterize proprioceptive sensations in the missing limb of upper limb amputees using nerve stimulation, and to develop advanced controllers for moving a prosthesis. Proprioceptive sensations are the sensations that tell individuals where their hand is in space, and if it is moving. The research team uses Functional Electrical Stimulation (FES), which involves applying small electric currents to the nerves. These signals are then transferred to the brain just like the information about the individual's intact hand used to be transferred to their brain. This study will test different placements for stimulation and determine which one(s) provide the individual with proprioceptive sensations. The investigators want to know what the participants feel and if the investigators can use proprioceptive sensation to give the participants information about limb movement and position.

Description:

Hands are the primary means of interacting with the world, and Veterans who have lost a hand must cope with diminished functional and sensory capabilities. While myoelectric prostheses can restore the basic grasping function of the lost hand, many amputees abandon use of prostheses because current prosthetic options do not meet their needs. In addition, many amputees struggle with phantom pain and psychosocial deficits following limb loss that are not fully mitigated by current treatments.

In the normal sensorimotor system, proprioception, which is the sense of limb position and movement, is critical for informing motor plans and correcting errors in movement. In addition, proprioception plays a key role in body ownership, agency, and phantom pain. Despite its importance, proprioception is absent in current prosthetic options.

The goal of the proposed project is to make upper limb prosthetic devices more natural and useful for Veterans who have lost a hand by providing proprioceptive feedback about prosthesis postures and movements. The central hypothesis is that effectively closing the loop between a prosthesis user and their device requires that the sensory inputs and control outputs closely mimic the underlying sensorimotor neural processes of the body schema. The investigators will examine integration of artificial proprioception with prosthesis control in three trans-radial and three trans-humeral amputees using the investigators' implanted neural-interfacing system.

Aim 1. Characterize proprioceptive sensations elicited by peripheral nerve stimulation. The investigators will test time-varying Peripheral Nerve Stimulation (PNS) patterns and examine the impact on the kinematics of the evoked proprioceptive percept using position matching with the contralateral intact limb and multivariate regression analyses. The investigators will investigate paired agonist-antagonist stimulation strategies and compare the discriminability between agonist-only and paired agonist-antagonist strategies using psychometric tests.

Aim 2. Investigate the mechanisms of stimulation-evoked proprioception. The neurophysiological basis of proprioception from PNS is unknown. To investigate whether proprioceptive percepts originate from direct afferent activation or indirect recruitment via direct muscle activation, the investigators will perform a motor block of the residual forearm of trans-radial participants and examine changes to the proprioceptive percepts. In trans-humeral participants, Targeted Muscle Reinnervation will be performed at the time of system implant, and percepts will be compared before and after muscle ingrowth.

Aim 3. Determine the integration of proprioceptive stimulation with motor control during posture matching. To restore proprioception to Veterans during active prosthesis use, PNS-evoked percepts must be integrated with voluntary limb control. The investigators will determine the impact of proprioception on motor control through a virtual reality posture matching task and compare performance with velocity and position-based prosthetic hand controllers with and without proprioceptive PNS. Second, the investigators will determine the impact of voluntary control on the perception of PNS-evoked proprioception through a psychometric dissimilarity rating task. Third, the investigators will assess the impact of artificial proprioception on embodiment via surveys.

The project will be the first to investigate the sensorimotor integration of proprioception from PNS in a broad population of upper-limb amputees and with both position and velocity controllers. The study will provide important information about the kinematics of artificial proprioception and the role of direct muscle activation in forming proprioceptive percepts. The investigators expect that knowledge gained in this proposal will improve prosthesis utility and acceptance for Veterans with limb loss and will advance prosthetic hand technology and standard of care in the neurorehabilitation field.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 6
• Est. completion date: December 31, 2025
• Est. primary completion date: December 31, 2025
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• Unilateral upper limb amputation above or below the elbow with fully healed and healthy surgical sites

• Viable peripheral nerve function in the residual limb

• Volitional activity of the residual muscles in the amputated limb

• Medically fit to undergo general anesthesia

• Fitted with a prosthesis by a certified prosthetic and orthotic specialist (CPO) and at least one month of experience using a prosthesis

• Willingness and availability to follow the study protocol

• Recommendation of a psychologist that the subject is mentally competent and capable of completing the study-related activities

Exclusion Criteria:

• Bilateral upper limb amputation

• Inability to speak English

• Medically unfit to undergo surgery

• Pregnancy, or those who are of childbearing potential, unwilling to prevent pregnancy during the trial

• Uncontrolled diabetes

• Active infection or open sores on the residual limb

• History of frequent infection or sores with unknown cause

• Inability to provide informed consent or follow experimental protocols

• Severe pain that would prevent the subject from completing study-related activities

Related Conditions & MeSH terms

• Upper Limb Amputees

Intervention

Device:
• Chronically Implanted Neural and Muscular Interface
Participants will be chronically implanted with neural and muscular interfaces to characterize proprioceptive sensations using Functional Electrical Stimulation (FES).

Locations

Country	Name	City	State
United States	Louis Stokes VA Medical Center, Cleveland, OH	Cleveland	Ohio

Sponsors (1)

Lead Sponsor	Collaborator
VA Office of Research and Development

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Magnitude of change in perceived joint position	Magnitude of change in perceived joint position, as measured by joint angle transducers in the Cyberglove.	This metric will be measured approximately each month for two years.

External Links

•   E. Gardner, J. Martin, in Principles of neural science (2000;