Combining Spinal Cord Transcutaneous Stimulation and Activity-based Training in Inpatient Rehabilitation to Facilitate Upper Limb Function of Individuals with Acute to Subacute Cervical Spinal Cord Injury

Participants will receive activity-based training (ABT) while receiving concomitant, active spinal stimulation (scTS) applied at the cervical and thoracic spinal segments over the dorsal skin with optimized and customized stimulation parameters. Round self-adhesive electrodes will be placed over the skin at the midline of spinous processes as cathodes and a pair of rectangular anodes electrodes will be placed over the anterior iliac crests of the pelvis. The stimulation waveform is rectangular pulse with 1-ms duration filled with a carrier frequency of 5kHz. Target simulation will be sub-threshold for UE muscle activation and verified by the absence of visible muscle contraction. The stimulation parameters will be adjusted as needed throughout the intervention course based on the participant's performance and comfort level. The intervention will be administered over 2 consecutive weeks, for 30mins/session and 5 sessions/week, as a part of their daily 3-hour therapy.

The sham-control group will go through ABT paired with sham stimulation to control for placebo effects associated with the perception of scTS. Stimulation will be delivered at one cervical location. No stimulation mapping procedure will be performed. During the training session, the stimulation intensity will be briefly ramped up to a level at which the participants report perceiving the stimulation, and then ramped down to 0mA at both the start and the end of session. The stimulator and electrodes will remain attached to the participant while receiving ABT training. The intervention will be administered over 2 consecutive weeks, for 30mins/session and 5 sessions/week, as a part of their daily 3-hour therapy.

articipants in ABT group will receive ABT only. ABT will concentrate on activities of gross UE movement, grasping, pinching, gross and fine motor skill. The hand grasp task will focus on grasping objects with different shapes and weights (i.e. weighted container and tennis ball) and placing/removing them from small storage container; the pinch task involves picking up, translating, and releasing small objects with varied sizes (i.e. blocks, dices, marble balls, nuts, etc.). The training therapist selects tasks based on participant's level of impairment and individual goals. The dosage of ABT will be 30 minutes/session, with approximately 15 minutes allocated on each side.