Spinal cord injuries commonly disrupt the transmission of motor commands from the brain to muscles and sever sensory feedback pathways essential for coordinating movement. Traditional rehabilitation methods often fail to restore this intricate sensorimotor loop, leaving patients unable to walk or sense limb positions accurately. The current study addresses these dual deficits through perilesional neuromodulation—implanting electrode arrays above and below the injured spinal segments to deliver patterned electrical stimulation designed to emulate natural spinal cord signals responsible for both voluntary muscle contraction and somatosensory feedback.

The clinical trial involved three participants paralyzed from the waist down following complete spinal cord lesions. Surgeons implanted miniature electrode arrays strategically placed proximal and distal to the injury site. Below-lesion stimulation focused on activating spinal circuits that command leg muscle activity, while stimulation above the lesion targeted sensory networks to simulate feedback from the lower limbs. This dual-site patterned stimulation represents the first successful attempt at integrating simultaneous motor facilitation and sensory substitution in humans with total paralysis, yielding encouraging functional outcomes.

Control over stimulation parameters was decentralized to the participants themselves through an innovative interface affectionately dubbed the “DJ board.” This control device, outfitted with an array of knobs and sliders, allowed subjects to modulate stimulation intensity, location, and frequency to achieve optimal flexion and relaxation patterns in leg muscles. This user-driven tuning not only personalized the therapeutic regimen but also empowered participants to engage dynamically in their own recovery, enhancing motivation and neuroplastic potential.

To refine these manually tuned patterns, researchers applied advanced machine learning algorithms capable of navigating the enormous parameter space inherent in spinal stimulation. Thomas Serre’s team at Brown trained predictive models correlating stimulation variables with desired muscle activation and sensory perception outcomes, enabling rapid convergence on highly effective, individualized neuromodulation schemes. This computational approach surmounted the limitations of trial-and-error optimization, ensuring precision in therapy delivery and robust adaptability.

Sensory feedback presented distinct challenges due to the disrupted ascending sensory pathways common in spinal injuries. Direct electrical stimulation of sensory nerves associated with the legs was impractical because these pathways were severed. Instead, the team adopted a sensory replacement strategy whereby stimulation above the lesion elicited perceivable sensations in intact dermatomes such as the chest or arms. Participants learned to reinterpret these artificial sensations as proxies for leg position and movement—an innovative form of sensory neuroplasticity that effectively substituted missing proprioceptive input.

Experimental validation demonstrated that participants could accurately identify knee angles based solely on varying intensities of sensations induced via spinal stimulation. Blindfolded during testing, subjects reported with high fidelity the flexion degree of their knees, signifying that the artificial sensory feedback was meaningful and actionable. This breakthrough has profound implications for restoring the sense of limb position, critical not only for walking but also for essential daily activities like transferring in and out of wheelchairs.

When combined, the motor and sensory stimulations facilitated remarkably coordinated walking motions on a treadmill, with participants harnessing stimulation to engage leg muscles while simultaneously perceiving foot contact with the ground. Supported by ceiling harnesses and physical therapy guidance, these individuals executed purposeful, rhythmic stepping, augmented by sensory cues that brought a new level of intentionality to their movements. Such integrated sensorimotor restoration significantly exceeds previous approaches that addressed movement or sensation in isolation.

Importantly, none of the participants reported adverse effects attributable to the electrode implants or electrical stimulation paradigms over the two-week in-hospital study. This safety profile paves the way for longitudinal studies targeting neurorehabilitation outside clinical settings. Researchers anticipate that prolonged use of coordinated spinal stimulation could catalyze neuroplastic remodeling, ultimately fostering improved voluntary motor control and functional independence in daily environments.

The multi-institutional collaboration drew on expertise spanning bioengineering, neurosurgery, cognitive neuroscience, and neurotechnology, exemplifying the power of interdisciplinary research to tackle complex biomedical challenges. This effort was supported by major federal funding entities including the Defense Advanced Research Projects Agency, the Department of Veterans Affairs, and the National Institutes of Health, underscoring the strategic importance of restoring sensorimotor function in spinal cord injury populations.

Looking forward, the team envisions augmenting their stimulation protocols with adaptive feedback loops and closed-loop control systems to further enhance precision and responsiveness. The integration of real-time sensory input with motor output modulation holds promise for developing next-generation neuroprosthetics capable of fully reinstating the seamless sensorimotor integration critical to human mobility. Such advances could revolutionize therapeutic paradigms for millions worldwide living with debilitating nervous system trauma.

This study marks a pivotal milestone in spinal cord injury research, illustrating the feasibility of bidirectional neurostimulation to replace lost sensorimotor function. By restoring both the ability to move and to perceive limb position, the researchers have brought us closer to the dream of fully regaining control and autonomy for individuals living with paralysis. This innovative approach is not merely an incremental advance but a transformative leap toward harnessing the power of neurotechnology to rewrite the lived experience of spinal cord injury.

Subject of Research: Restoration of sensorimotor functions in persons with complete spinal cord injury through perilesional electrical stimulation.

Article Title: Perilesional neuromodulation replaces lost sensorimotor function in persons with spinal cord injury

News Publication Date: 11-Mar-2026

Web References: http://dx.doi.org/10.1038/s41551-026-01627-5

Image Credits: Borton Lab / Brown University

Keywords: spinal cord injury, electrical stimulation, sensorimotor restoration, neurotechnology, neuromodulation, machine learning, rehabilitation, spinal neurosurgery, proprioception, neuroplasticity, bioengineering, clinical trial

However, the effects of EES on patients with incomplete SCI have yet to be conclusively established. Current evidence is limited by small sample sizes, variable long-term outcomes, and a narrow focus primarily on motor recovery. Furthermore, delineating the individual contributions of EES from concurrent physical therapy (PT) presents a critical methodological challenge, as their combined efficacy remains underexplored in controlled clinical contexts. Addressing this gap, researchers at Beijing Tiantan Hospital, Capital Medical University, led by Yihang Ren, designed a controlled, larger cohort study to rigorously evaluate the impact of EES combined with standardized PT across multiple neurological domains, encompassing sensation, muscle strength, spasticity, and autonomic functions in individuals with incomplete SCI.

The single-center, nonrandomized, and nonblinded cohort study spanned from October 2020 to April 2024, enrolling adult patients with incomplete spinal cord injuries classified by the ASIA grading system (grade ≥B) and injury levels above L1–L2, at least six months post-injury. Rigorous baseline assessments were conducted, including MRI, electromyography (EMG), somatosensory evoked potentials (SEP), and computed tomography (CT), to characterize demographic, clinical, and radiological profiles. Participants self-selected into an intervention group receiving EES plus PT (n=11) or a control group undergoing PT alone (n=10). Both groups engaged in an intensive, standardized physical therapy regimen focused on lower-limb functional training, cycling, quadriceps strengthening, ankle passive motion, and body-weight-supported treadmill exercises for 4–5 hours daily, supplemented by remote follow-up.

In the intervention arm, the surgical protocol involved implantation of a thoracolumbar epidural electrode (Medtronic 39565) connected initially to a temporary stimulator (Medtronic 37714), with intraoperative electrophysiological monitoring ensuring optimal electrode placement and stimulation parameter calibration—namely anode/cathode configuration, amplitude, pulse width, and frequency. Following a 7–10-day evaluation period confirming therapeutic benefit without adverse effects, permanent implantable stimulators (Medtronic 37714) were implanted subcutaneously. Stimulation protocols commenced on the first postoperative day, targeting major lower-limb muscle groups with iterative adjustments over two weeks. Patients were assessed at three timepoints: baseline, within 14 days post-EES surgery prior to PT commencement, and at a long-term follow-up between 19 and 25 months.

Comparative analyses revealed no significant difference between groups at baseline in demographics, injury characteristics, or neurological status (all P>0.05), validating internal comparability. Early postoperative evaluation at day 14 in EES+PT patients demonstrated marked improvements in sensory function and reduction in muscle spasticity (both P<0.001), although group-level changes in lower-limb strength, urinary and bowel function, and pain scores did not reach statistical significance. Notably, individual patient data indicated that roughly one-third exhibited enhanced muscle strength, and the majority experiencing neuropathic pain reported symptom alleviation.

Longitudinal outcomes over 19–25 months substantiated sustained and significant gains in the intervention group across multiple domains. EES combined with PT facilitated robust improvements in sensory scores, spasticity reduction, and urinary control (P<0.001 and P<0.05 respectively). Remarkably, 100% of EES+PT participants exhibited enhanced sensation and spasticity metrics, while substantial proportions also improved in urinary (6/11), motor strength (4/11), bowel function (4/11), and pain relief (4/5) parameters. In direct comparisons, EES+PT significantly outperformed PT alone in sensory, motor, spasticity, and urinary functions (P-values ranging from <0.01 to <0.0001). Although bowel function improvement favored the EES+PT group (57.1% recovery vs. 11.1% in PT-only), this result did not achieve statistical significance. Encouragingly, no electrode-related infections or displacements were reported throughout the follow-up period.

This pioneering investigation offers compelling evidence that EES integrated with standardized physical therapy yields considerable long-term benefits for patients with incomplete SCI, encompassing sensory restoration, strength augmentation, spasticity management, and autonomic improvements such as urinary control. The study also highlights potential advantages in bladder function and neuropathic pain relief, broadening the therapeutic scope of EES beyond motor recovery alone. The implant technology, paired with personalized stimulation protocols, appears safe and well-tolerated, setting the stage for broader clinical adoption.

Looking forward, the authors emphasize the importance of further research incorporating controlled rehabilitation content and intensity, extended follow-up durations to evaluate sustainability, and objective sensory assessments including electrophysiological measurements. Unraveling the underlying neuroplasticity mechanisms will enrich the understanding of EES’s role in spinal network reorganization. Moreover, controlling for confounding variables like age and comorbidities, and comparing EES+PT against alternative treatments in randomized designs, will be essential to conclusively reaffirm its efficacy. Personalized treatment paradigms tailored to individual patient profiles are envisioned to optimize therapeutic outcomes.

The investigative team includes Yihang Ren, Lifen Mo, Junlin Lu, Ping Zhu, Ming Yin, Wenqing Jia, Fengyan Liang, Xiaodi Han, and Jizong Zhao, and their groundbreaking work is detailed in the paper entitled “Epidural Electrical Stimulation for Functional Recovery in Incomplete Spinal Cord Injury.” Published in the journal Cyborg and Bionic Systems on July 22, 2025, this study underscores significant advancements in neurorehabilitation strategies for SCI. Supported by prestigious funding bodies such as the National Natural Science Foundation of China and regional technology science initiatives, this research marks a critical milestone in spinal injury therapeutics.

As spinal cord injury continues to challenge neuroscience and rehabilitation disciplines, this study offers a beacon of progress. By combining cutting-edge neuromodulation technology with rigorous physical therapy, EES emerges as a transformative approach capable of restoring multiple functional domains lost to SCI. The implications for clinical practice, patient quality of life, and future innovation in neurorehabilitation are profound, inviting further exploration and rapid translation of these findings into widespread clinical settings.

Subject of Research: Epidural electrical stimulation combined with physical therapy for functional recovery in incomplete spinal cord injury

Article Title: Epidural Electrical Stimulation for Functional Recovery in Incomplete Spinal Cord Injury

News Publication Date: July 22, 2025

Web References: DOI: 10.34133/cbsystems.0314

Image Credits: Yihang Ren, Beijing Tiantan Hospital, Capital Medical University

Keywords: Life sciences, Mathematics, Physical sciences