New system integrates neuroprosthetics with robotics to improve mobility after spinal cord injury

Spinal cord injuries are life-altering, often leaving individuals with severe mobility impairments. While rehabilitation robotics-devices that guide movement during therapy-have improved training for those with spinal cord injuries, their effectiveness remains limited. Without active muscle engagement, robotic-assisted movement alone does not sufficiently retrain the nervous system.

A team at NeuroRestore, led by Grégoire Courtine and Jocelyne Bloch, has now developed a system that seemlessly integrates an implanted spinal cord neuroprosthesis with rehabilitation robotics. The researchers' device delivers well-timed electrical pulses to stimulate muscles in harmony with robotic movements, resulting in natural and coordinated muscle activity during therapy. The neuroprosthetics innovation leveraged the the robotic expertise of Professor Auke Ijspeert's lab at EPFL. This advancement not only enhances immediate mobility but also fosters long-term recovery.

The seamless integration of spinal cord stimulation with rehabilitation or recreational robotics will accelerate the deployment of this therapy into the standard of care and the community of people with spinal cord injury."

Grégoire Courtine, EPFL

This adaptability ensures that rehabilitation professionals can incorporate this technology into existing rehabilitation protocols worldwide. Combining therapies also presents significant challenges, as each requires precise synchronization. Spinal cord stimulation strategies must be modulated in both space and time to match the patient's movement, and integrating them with widely used robotic rehabilitation systems requires a flexible and adaptable framework. 

The technology relies on a fully implanted spinal cord stimulator that delivers biomimetic electrical epidural stimulation (electrical epidural stimulation). Unlike traditional functional electrical stimulation, this method activates motor neurons more efficiently by mimicking natural nerve signals. 

The researchers integrated electrical epidural stimulation with various robotic rehabilitation devices-including treadmills, exoskeletons, and stationary bikes-ensuring that stimulation is precisely timed with each phase of movement. The system uses wireless sensors to detect limb motion and automatically adjust stimulation in real time, allowing for a seamless user experience.

In a proof-of-concept study involving five individuals with spinal cord injuries, the combination of robotics and electrical epidural stimulation resulted in immediate and sustained muscle activation. Not only did participants regain the ability to engage muscles during robotic-assisted therapy, but some also improved their voluntary movements even after the stimulation was turned off.

The researchers also worked closely with rehabilitation centers to test how well the stimulation system integrated with widely used robotic devices. "We visited multiple rehabilitation centers to test our stimulation technology with the robotic systems they routinely use, and it was incredibly rewarding to witness their enthusiasm," say .NeuroRestore researcher Nicolas Hankov and BioRob researcher Miroslav Caban, the study's first authors. "Seeing firsthand how seamlessly our approach integrates with existing rehabilitation protocols reinforces its potential to transform care for people with spinal cord injury by providing a technological framework that is easy to adopt and deploy across multiple rehabilitation environments."

The study also showed the potential of this approach beyond clinical settings, as participants used the system to walk with a rollator and cycle outdoors, validating its real-world impact.

This innovative technology offers new hope for individuals with spinal cord injuries, presenting a more effective rehabilitation approach than robotics alone. By making rehabilitation more dynamic and engaging, it has the potential to significantly enhance recovery outcomes. Future clinical trials will be needed to establish long-term benefits, but the initial results suggest that integrating neuroprosthetics with rehabilitation robotics could redefine mobility restoration after paralysis.

List of contributors

• EPFL Neuro X
• Lausanne University Hospital (CHUV) and University of Lausanne (UNIL)
• Defitech Center for Interventional Neurotherapies (.NeuroRestore)
• EPFL Biorobotics Laboratory
• ONWARD Medical
• Bern University of Applied Sciences
• VAMED Management and Service Switzerland AG
• ETH Zurich Sensory-Motor Systems Lab
• University of Zurich Spinal Cord Injury Center
• Hocoma AG
• Medtronic
• Oxford University
• GBY (Go-by-Yourself) SA
• Université de Bordeaux Institut des Maladies Neurodégénératives
• Zurich University of Applied Sciences (ZHAW)
• MyoSwiss AG