Ibarra, Antonio

Background: Central cord syndrome (CCS) is the most common incomplete spinal cord injury, producing more severe motor deficits in the upper than lower extremities and impairing sensory and autonomic function. Although transcutaneous spinal cord stimulation (tSCS) has shown benefits in motor and sensory recovery after spinal cord injury, studies have not explicitly documented whether CCS subjects were included. The aim of this study was to assess the effects of tSCS over 12 weeks on motor and sensory outcomes in a subject with CCS. Methods: A 20-year-old male with a C7 injury was evaluated at baseline and after 12 weeks with the American Spinal Cord Injury Impairment scale, Modified Ashworth Scale, Penn and Spasm Frequency Scale, 3-Meter Walk Test and 6-Minute Walk Test, 9-Hole Peg Test, Box and Block Test, hand dynamometry, and lower-limb EMG. tSCS was applied between T9 and L1 at 30 Hz. Results: At 12 weeks, upper-limb motor and sensory scores improved, while spasm frequency and hand spasticity were reduced. Manual dexterity improved bilaterally in the 9-Hole Peg and Box and Block Tests, with a 2 kg gain in right-hand grip strength. In the 6-Minute Walk Test, the distance covered increased from 224.4 m to 295.2 m, and a 1.36 s reduction in 3-Meter walking time was achieved. Conclusions: tSCS improved motor and sensory function and reduced spasticity and spasms. These findings suggest that tSCS may serve as an effective complementary intervention for motor and sensory rehabilitation in individuals with mild cervical injuries, including CCS.

Abstract Background Spinal cord injury causes motor, sensory, and autonomic impairments. Transcutaneous spinal cord stimulation (tSCS) has shown potential to improve autonomic regulation, particularly cardiovascular and bladder control. Heart rate variability (HRV) serves as a non-invasive marker of autonomic balance, reflecting modulation of cardiac sympathetic and parasympathetic activity. The purpose of this study was to evaluate the effect of combined tSCS and physical therapy (tSCS + PT) on HRV and autonomic function metrics in chronic spinal cord injury. Methods. Eight participants (2 with tetraplegia, 6 with paraplegia) received tSCS at 30 Hz targeting T11–L1 or C5–T1, depending on injury level. Each underwent two tSCS + PT sessions per week for 12 weeks, followed by a 4-week washout period. Autonomic assessments included the Autonomic Standard Evaluation Form (ASAF), Neurologic Bladder Symptoms Score (NBSS), blood pressure, heart rate, SpO2%, and core temperature. Electrocardiograms were recorded pre- and post-tSCS + PT at baseline, 12, and 16 weeks. Results. Baseline effects of tSCS + PT revealed increased time-domain HRV parameters, suggesting enhanced cardiac parasympathetic activation (PSA). After 12 weeks, these parameters decreased, suggesting reduced cardiac PSA and enhanced sympathetic activation (SA). Similar results were found with frequency-domain parameters. Time-and frequency-domain parameters tended to return toward baseline after the 4-week therapy suspension. Two commonly reported HRV parameters, SDNN and RMSSD, showed large effects (g = 1.64, CI 95% [0.30, 2.98], and g = 1.23, CI 95% [0.11, 2.42], respectively) at 12 weeks when comparing pre- vs. post-tSCS + PT. Moderate, subject-related differences across evaluations were found in ASAF and NBSS (p > 0.05). Physiological metrics across time points did not show statistically significant differences (p > 0.05). Physiological metrics across time points did not show statistically significant differences (p > 0.05). Conclusions Combined tSCS + PT elicited improvements in autonomic clinical measures, without statistically significant changes in time-domain or frequency-domain HRV parameters. Nonetheless, trends and size effect in SDNN and RMSSD suggested that tSCS + PT induced midterm SA and a transient PSA immediately post-tSCS + PT. The partial recovery of HRV after tSCS withdrawal indicates that the observed autonomic changes were therapy-related.