While physical exercise remains the foundation for any rehabilitation therapy, the team seeks to improve the benefits of exercise by combining it with the concept of "Fire Together, Wire Together" - when brain stimulation is synchronized with spinal cord stimulation, nerve circuits in the spinal cord strengthen - a phenomenon termed "Spinal Cord Associative Plasticity", or SCAP.
This project will build on the team's promising preliminary findings. When one pulse of brain stimulation is synchronized with one pulse of cervical spinal stimulation, hand muscle responses are larger than with brain stimulation alone or unsynchronized stimulation. However, the team does not know the best ways to apply SCAP repetitively, especially in conjunction with exercise, to increase and extend improvements in clinical function. Do ideal intervention parameters vary across individuals, or do they need to be customized?
The team will take a systematic approach with people who have chronic cervical SCI to determine each person's best combination of SCAP with task-oriented hand exercise. Participants will undergo up to 53 intervention, verification, and follow-up sessions over a period of 6 to 10 months each. The team will measure clinical and physiological responses of hand and arm muscles to each intervention.
Regaining control over hand function represents the top priority for individuals with cervical SCI. Furthermore, this approach could be compatible with other future interventions, including medications and cell-based treatments.
Age between 18-85 years.
Must have stable prescription medication for 30 days prior to screening
Must be able to: abstain from alcohol, smoking and heavy caffeine consumption on the day of each experiment; abstain from recreational drugs for the entirety of the study; commit to study requirements (i.e., 53 visits); provide informed consent.
Score of 1-4 (out of 5) on manual muscle testing of finger extension, finger flexion, or finger abduction in left or right hand.
Personal or extensive family history of seizures;
Ventilator dependence or patent tracheostomy site;
History of stroke, brain tumor, brain abscess, or multiple sclerosis;
History of severe head trauma requiring neurosurgery;
Single group
Synaptic Pairing Interval
Procedure/SurgeryOptimize interstimulus pairing between brain and spinal cord stimulation.
Frequency
Procedure/SurgeryCompare 2 Hz continuous to intermittent theta burst frequency
Bouts
Procedure/SurgeryCompare effects of 1, 2, or 4 bouts of SCAP
Spacing
Procedure/SurgeryCompare 6 versus 12 minutes of rest in between bouts of SCAP
Exercise
Procedure/SurgeryTask-oriented hand exercises
SCAP plus Exercise
Procedure/SurgeryCompare interleaved versus serial bouts of SCAP and exercise.
Amplitude of motor evoked potential at the target muscle.
The primary neurophysiological outcome will be corticospinal excitability measured at the target muscle. The target muscle will be determined during the first evaluation session, with preference for first dorsal interosseous (FDI), abductor pollicis brevis (APB), or extensor carpi radialis (ECR) muscles based on muscle excitability and consistency. TMS recruitment curves will be collected. The amplitude of target muscle responses to TMS and spinal cord stimulation will be compared after the various interventions.
Pinch and grip strength
Maximal isometric pinch strength will be measured in key-pinch (lateral edge of the index finger and the thumb) and tip-to-tip (tips of first and third finger) configurations using a pinch dynamometer. Grip strength will be measured using a hand dynamometer. For each type of pinch or grip, three trials will be conducted by holding the dynamometer with maximal volitional force for 3-5 seconds, with at least 30 seconds or more between trials. The highest achieved value will be used for analysis.
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Bronx VA Medical Center
Lead sponsor
Bronx Veterans Medical Research Foundation, Inc
Collaborator
New York State Department of Health
Collaborator
