Operant Conditioning of the Wrist Extensor Motor Evoked Potential to Target Corticospinal Plasticity and Upper Limb Motor Recovery After Cervical Spinal Cord Injury
Medical University of South Carolina
Summary
Individuals with chronic cervical spinal cord injury will complete a 10-week training protocol where participants receive non-invasive brain stimulation and feedback on the size of the corresponding muscle response (wrist extensor). Investigators will assess the impact of the brain stimulation training on 1) the brain-to-spinal cord-to-muscle connection and 2) motor functions of the arm and hand. Also, brain and spine magnetic resonance imaging will be collected before and after the training. The imaging measurements will tell investigators about how spinal damage, brain function, and brain structure relate to motor presentation and the response to the training.
Description
Corticospinal function is essential in generating and controlling voluntary movements. Cervical spinal cord injury (SCI) disrupts corticospinal connections, therefore, often results in weak voluntary activation of muscles and impaired motor control in the upper limb (UL). An intervention that improves corticospinal function could enhance motor function recovery; however, such interventions are not currently readily available to people with incomplete SCI. Operant up-conditioning of a motor evoked potential (MEP) to transcranial magnetic stimulation (non- invasive brain stimulation) that can in…
Eligibility
- Age range
- 18+ years
- Sex
- All
- Healthy volunteers
- No
Inclusion Criteria: * Adult (≥18 yrs old) * A history of injury to spinal cord at or above C6 * \>6 months post SCI * 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. Exclusion Criteria: * Motoneuron injury * Medically unstable condition * Cognitive impairment * A history of epileptic seizures * Metal implants in the cranium * Implanted biomedical device in or above the chest (e.g., a cardiac pacemaker, cochlear…
Interventions
- BehavioralUp-conditioning of the wrist extensor motor evoked potential
At the beginning of each session, EMG recording and nerve stimulating electrodes are placed over the arm. In all sessions, MEPs will be measured while the sitting subject provides a pre-set level of background muscle EMG with joint angles fixed. In 225 control trials of each baseline sessions and the first 20 trials of conditioning sessions the subject will receive no feedback as to MEP size (i.e., control MEPs). In 225 conditioning trials of each conditioning session, the subject will be encouraged to increase the target muscle MEP, and will receive immediate feedback as to whether MEP size was above a criterion (i.e., whether the trial was a success).
Location
- Medical University of South CarolinaCharleston, South Carolina