Non-Invasive Cervical Spinal Stimulation Enhances Upper Limb Recovery: Multicenter RCT Outcomes in Chronic SCI

Introduction: Globally, about 15 million people live with spinal cord injury (SCI), with nearly 500,000 new cases annually; approximately half experience tetraplegia, severely limiting upper limb use. Rehabilitation is often restricted to compensatory strategies and hampered by limited resources. Neuromodulation, particularly spinal cord stimulation, offers new therapeutic hope for chronic SCI. Transcutaneous spinal cord stimulation (TSS) has emerged as a non-invasive alternative to epidural spinal stimulation, promoting spinal excitability and facilitating both motor and autonomic functions in individuals with SCI.

Methods: The ASPIRE Study is a 14 site, randomized, double-masked, parallel group, study aimed to evaluate the short-term improvement in upper limb motor function for chronic SCI patients receiving TSS for 8 consecutive weeks in conjunction with activity based therapy. The study consisted of a 1-week screening period, an 8-week therapy period, and a follow-up visit at 4-weeks after cessation of treatment. In the active group, TSS was applied at the cervical level, delivering TSS for 45-60 minutes, in conjunction with traditional rehabilitative therapy. The sham group received a minimal dose of stimulation for no greater than 10 seconds per activity, to mimic the sensation of TSS while limiting a neuromodulation effect, in conjunction with traditional rehab therapy.

Results: The primary endpoints were the safety and effectiveness of TSS stimulation with PT/OT, relative to Sham Stimulation (PT/OT alone) in restoring upper extremity strength.128 subjects were enrolled, with 120 completing the study through follow-up. No serious adverse events related to the TSS system were reported. The primary endpoint of superiority of the active group was met in the per protocol analysis group (n=55 active; n=43 sham) as follows:

- Average Upper Extremity Motor Score (UEMS) mean change in the active group from Baseline to Week 8 (primary endpoint) was 2.0 ± 3.1 in the active group versus 1.7 ± 2.6 in the sham group. These results were sustained at Week 12 in the active group but reduced slightly in the sham group.
- Functional measures of Capabilities of Upper Extremity Test (CUE-T) was assessed as a functional measure. Those in the active group had a 4.4 ± 6.2 mean score improvement on the CUE-T, versus 3.2 ± 6.1 mean score change in the sham group. ASIA A, B, and C subgroups met MID for CUE-T functional improvement (≥4).
-Tertiary endpoints reveal improvements in light touch sensation and quality of life.
-Additional subgroup analysis results for ASIA A, B,C, Dr are available in the attached charts.

Conclusion: Transcutaneous Spinal Cord Stimulation, combined with traditional rehabilitation, provides a safe and effective option for improving upper extremity strength, function, sensation, and quality of life in individuals with chronic spinal cord injury (SCI), supporting long-term recovery and independence. Improvements in strength and function were largely sustained at 12-week follow up.

Keyword 1: Transcutaneous Spinal Stimulation (TSS)

Keyword 2: Chronic SCI

Keyword 3: Upper limb motor recovery

Keyword 4: upper limb function

Keyword 5: cervical SCI

References : 1. García, Á., Serrano-Muñoz, D., Taylor, J., Avendaño-Coy, J., & Gómez-Soriano, J. (2019). Transcutaneous Spinal Cord Stimulation and Motor Rehabilitation in Spinal Cord Injury: A Systematic Review. Neurorehabilitation and Neural Repair, 34, 12 - 3. https://doi.org/10.1177/1545968319893298.
2. Martin, R. (2021). Utility and feasibility of Transcutaneous spinal cord stimulation for patients with incomplete SCI in therapeutic settings: A review of topic. Frontiers in Rehabilitation Sciences, 2, 724003.
3. Richard-Denis, A., Chatta, R., Thompson, C., & Mac-Thiong, J. M. (2020). Patterns and predictors of functional recovery from the subacute to the chronic phase following a traumatic spinal cord injury: a prospective study. Spinal cord, 58(1), 43-52.
4. Shi, C., Chen, Y., Ye, L., Feng, J., Dong, G., & Lu, S. (2024). Transcutaneous spinal cord stimulation on motor function in patients with spinal cord injury: A meta-analysis.. NeuroRehabilitation, 54 4, 563-573 . https://doi.org/10.3233/nre-240057.
5. Trumbower, R. D. (2018). Stimulating the Injured Spinal Cord: Plenty to Grasp. Journal of Neurotrauma, 35(18), 2143.

Funding: N/A