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.
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 increase corticospinal excitability for the targeted muscle may be able to fill this gap. The overarching hypothesis is that targeting beneficial plasticity to the corticospinal pathway can change the brain and spinal cord and improve upper limb motor function in people with chronic cervical SCI. As initial steps towards testing this, the proposed project aims to apply MEP operant up-conditioning in the wrist extensor of the affected UL, improve corticospinal activation of the wrist extensor, and thereby improve motor functions in which the wrist is involved in individuals with cervical SCI. Recent studies suggest that MEP up- conditioning is feasible and can increase MEP size that reflects corticospinal excitability. Building on those studies, this project will examine the effects of wrist extensor MEP operant up-conditioning in people with chronic cervical SCI. Individuals with weak wrist extension due to incomplete cervical SCI will undergo a standard MEP up-conditioning protocol (6 baseline and 24 up-conditioning sessions over 10 weeks). Before and after the intervention period, neurophysiological measurements, clinical and functional assessments, neuroimaging of the spinal cord and brain will be performed. The results will facilitate development and clinical translation of MEP operant conditioning as a novel non-invasive therapy that may complement other therapies and further enhance motor function recovery in people with SCI or other disorders.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
11
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).
Medical University of South Carolina
Charleston, South Carolina, United States
RECRUITINGExtensor Carpi Radialis (ECR) Motor Evoked Potential (MEP) amplitude
Size of MEP elicited at the fixed stimulus intensity (e.g., \~ 10-15% maximum stimulator output) of transcranial magnetic stimulation (TMS) above motor threshold) (in %M wave maximum amplitude)
Time frame: Reported as an average of the 6 baseline sessions (over weeks 1-2) and average of the last 6 conditioning sessions (over weeks 8-10)
Maximum Voluntary Contraction - ECR
Maximum voluntary contraction measured by electromyography (EMG) (in mV); average of two trials
Time frame: Reported as an average of the 6 baseline sessions (over weeks 1-2) and average of the last 6 conditioning sessions (over weeks 8-10)
Capabilities Upper Extremity Test (CUE-T)
The CUE-T is an objective clinical measure of a person with tetraplegia's ability to complete actions with the arm and hand. This scale measures motor function. It consists of 19 tasks (17 unilateral, 2 bilateral). Scoring is based completion of the action, number of repetitions, or time to complete depending on the item and converted from raw score to 5-point scale (0-4, 4 is best).
Time frame: Baseline, after the 24th conditioning session (typically within 1 week), 1 month and 3 months post
Graded and Redefined Assessment of Strength, Sensibility, and Prehension (GRASSP)
The GRASSP is a clinical impairment measure to assess sensorimotor hand function in people with cervical SCI. The GRASSP tests 3 domains of hand function including strength, sensibility, and prehension. The GRASSP contains 6 tasks for each side scored from 0-5 for a possible score of 0-30 per side or 0-60 total, where higher scores are better.
Time frame: Baseline, after the 24th conditioning session (typically within 1 week), 1 month and 3 months post
Spinal Cord Independence Measure (SCIM III)
The SCIM is a self-report survey of daily activity independence in self-care, respiration and sphincter management, and mobility. The scores range from 0-100, where higher scores represent greater independence.
Time frame: Baseline, after the 24th conditioning session (typically within 1 week), 1 month and 3 months post
Life Situation Questionnaire Revised (LSQ-R)
The LSQ-R is a self-report survey of quality of life that contains 20 life satisfaction items and 30 life problems items. All items are evaluated using a 5-point scale. For the satisfaction items, a score of 1 indicates "very dissatisfied," while a score of 5 denotes "very satisfied." For the problems items, a score of 1 represents "no problem," and a score of 5 signifies a "major problem."
Time frame: Baseline, after the 24th conditioning session (typically within 1 week), 1 month and 3 months post
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