Motoneuron Recruitment and Motor Evoked Potential Up-Conditioning (MEP) in Spinal Cord Injury (SCI)

NCT ID: NCT07179822

Last Updated: 2025-11-26

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 15 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-11-03
• Study Completion Date: 2027-09-30

Brief Summary

The purpose of this research study is to examine the effect of a brain stimulation training to improve the function of brain-spinal cord- muscle connections. Because brain-to-muscle pathways are very important in our movement control, restoring function of these pathways may improve movement problems after injuries. Spinal cord injury causes damage to the brain-to-muscle connection. However, when the injury is "incomplete", there is a possibility that some of the brain-to-muscle pathways are still connected and may be trained to improve movement function. For examining brain-to-muscle pathways, investigators use a transcranial magnetic stimulator. Investigators hope that the results of this research study will help us develop new treatments for people who have movement disabilities. This study will require about 42 visits over the first 14 weeks, and another 6 visits over an additional 3 months. Each visit will take about 1 ½ hours.

Detailed Description

Regaining arm/hand function is one of the top priorities of individuals with tetraplegia and is a challenging problem, partly due to the complex nature of upper limb motor function. Through mass practice and conventional therapy, functions can be restored partially, likely through compensation rather than induction of relevant corticospinal plasticity. In such cases, corticospinal recruitment of motoneurons and resulting muscle activation could remain impaired and continue to limit function recovery. In people with incomplete SCI, voluntary activation of the muscles below the injury level is often diminished, due at least partly to impaired motor unit behaviors. Abnormal motoneuron recruitment and motor unit firing, also found in other CNS disorders, would certainly hinder effective production of motor functions. Thus, to enhance upper limb motor rehabilitation beyond what conventional therapy has been able to achieve, a method to improve corticospinal recruitment of a targeted pool of motoneurons would be needed. Here, investigators hypothesize that wrist extensor MEP up-conditioning can improve forearm motor functions in people with cervical SCI by increasing the corticospinal excitability and improving corticospinal recruitment of wrist extensor motoneurons.

Conditions

Spinal Cord Injuries and Disorders (SCI/D); Spinal Cord Injury

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: OTHER
• Blinding Strategy: NONE

Study Groups

Motor Evoked Potential (MEP) Operant Conditioning

This intervention requires 6 baseline visits and 24 intervention visits, each of which is approximately 1.5 hours.

Group Type: EXPERIMENTAL

Motor Evoked Potential (MEP) Operant Conditioning

Intervention Type: BEHAVIORAL

Operant conditioning is a method to induce behavioral learning based on the consequence (reward) of the behavior. With operant conditioning of the motor evoked potential (MEP), the neuronal excitability and behavior of the corticospinal pathway that involves production of MEP is targeted and trained (i.e., up-trained with up-conditioning). The individual is rewarded only for changing the target muscle's MEP size without changing background muscle activity. Since MEP size reflects the corticospinal excitability at or just before the time of stimulation, during MEP up-conditioning trials, the individual is urged to increase the corticospinal excitability for the target muscle.

Interventions

Motor Evoked Potential (MEP) Operant Conditioning

Operant conditioning is a method to induce behavioral learning based on the consequence (reward) of the behavior. With operant conditioning of the motor evoked potential (MEP), the neuronal excitability and behavior of the corticospinal pathway that involves production of MEP is targeted and trained (i.e., up-trained with up-conditioning). The individual is rewarded only for changing the target muscle's MEP size without changing background muscle activity. Since MEP size reflects the corticospinal excitability at or just before the time of stimulation, during MEP up-conditioning trials, the individual is urged to increase the corticospinal excitability for the target muscle.

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

• Adult (≥18 yrs old)
• a history of injury to spinal cord at or above C6
• neurologically stable (>1 year post SCI)
• medical clearance to participate
• weak wrist extension at least unilaterally
• expectation that current medication will be maintained without change for at least 3 months.

• Stable use of anti-spasticity medication (e.g., baclofen, diazepam, tizanidine) is accepted. (Because only neurologically stable subjects will enter this study, medication changes will be unlikely.)
• In participants with bilateral wrist extension weakness in whom Extensor Carpi Radialis (ECR) MEP can be elicited in both arms, the more severely impaired arm is studied. In participants with unilateral wrist weakness or in participants with bilateral wrist weakness in whom an ECR MEP can be elicited in only one arm, that arm is studied.

Exclusion Criteria

• motoneuron injury
• unstable medical condition
• cognitive impairment (because the studied intervention is a learning-based intervention)
• a history of epileptic seizures
• a pre-existing or confounding neurological condition (e.g., history of MS, Stroke, Parkinson's disease)
• metal implants in the cranium
• implanted biomedical device in or above the chest (e.g., a cardiac pacemaker, cochlear implant)
• no measurable MEP elicited in the ECR
• inability to produce any voluntary ECR EMG activity
• extensive use of functional electrical stimulation to the arm on a daily basis (as it may interfere with or augment the effects of MEP conditioning itself)
• pregnancy (due to changes in posture and potential medical instability)
• inability or unwillingness of subject or legal guardian/representative to give informed consent

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Northwestern University

OTHER

Sponsor Role: collaborator

National Institutes of Health (NIH)

NIH

Sponsor Role: collaborator

Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

NIH

Sponsor Role: collaborator

Medical University of South Carolina

OTHER

Sponsor Role: lead

Responsible Party

Aiko Thompson

Professor-Faculty

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Aiko Thompson, PhD

Role: PRINCIPAL_INVESTIGATOR

Medical University of South Carolina

Locations

Medical University of South Carolina

Charleston, South Carolina, United States

Site Status: RECRUITING

Countries

United States

Central Contacts

Occupational Therapist

Role: CONTACT

stecb@musc.edu

(843) 792-6313

Facility Contacts

Blair Dellenbach, MSOT

Role: primary

stecb@musc.edu

843-792-6313

Other Identifiers

1R21HD118383

Identifier Type: NIH

Identifier Source: secondary_id

View Link

Pro00145581

Identifier Type: -

Identifier Source: org_study_id