Swiss Neuroscientists and Neurologists Team up to Enable Paraplegic Patients to Walk Again.
Precisely-timed electrode stimulation in the spinal cord activates leg muscles in response to brain signals, and enables patients to walk.
Paired with weight-assisted therapy, three paraplegics that suffered spinal cord injuries many years ago are now able to walk with crutches or a walker. What is more, all patients involved in the study recovered voluntary control of leg muscles that had been paralyzed for many years.
“All the patients could walk using body weight support within one week. I knew immediately that we were on the right path,” Jocelyne Bloch, CHUV Neurosurgeon
The study, called STIMO (STImulation Movement Overground), establishes a new treatment framework for improving recovery from spinal cord injury.
Walking again after spinal cord injury – © EPFL+CHUV, YouTube
Deep understanding of the neural mechanisms from years of prior research
In the video, Dr Grégoire Courtine, Group Leader and Neuroscientist at the EPFL, Switzerland, explained how the findings that the human patients could walk were encouraging to see, but were not that surprising, as years of research in rodent models had shown this approach works. As he explains:
“Our findings are based on a deep understanding of the underlying mechanisms which we gained through years of research on animal models. We were thus able to mimic in real time how the brain naturally activates the spinal cord.”
Adding: “The exact timing and location of the electrical stimulation are crucial to a patient’s ability to produce an intended movement. It is also this spatiotemporal coincidence that triggers the growth of new nerve connections,” says Courtine.
Stimulation as precise as a Swiss watch
“All the patients could walk using body weight support within one week. I knew immediately that we were on the right path,” adds CHUV neurosurgeon Jocelyne Bloch, who surgically placed the implants in the patients.
Explaining: “The targeted stimulation must be as precise as a Swiss watch. In our method, we implant an array of electrodes over the spinal cord which allows us to target individual muscle groups in the legs. Selected configurations of electrodes are activating specific regions of the spinal cord, mimicking the signals that the brain would deliver to produce walking.”
This is an unprecedented level of precision in electrical stimulation of spinal cord neurons. The more physiologically relevant stimulation enabled the patients to better learn how to coordinate their brains’ intention to walk with the targeted stimulation and they were able to do this with body-weight support after only 1-week of training.
Reinforcing the neural circuitry that controls walking
This is a vast improvement on previous rehabilitation methods that have been tried. And the system enabled patients to train outside on different terrains for longer periods of time.
The authors say these extended high-intensity training sessions were crucial for triggering activity-dependent plasticity, the natural reorganization and reinforcement of the connections in the nervous system between the brain, the spinal cord nerves and the leg muscles that enable walking. Which lead to improved motor function even when the stimulation was switched off.
The next steps
Targeted and precise stimulation of the spinal cord nerves in relation to brain activity is a powerful combination that has helped these patients regain the ability to walk. The authors say the next steps are to try this approach earlier, with patients that have only just suffered a spinal injury, to see if intervening earlier can even further improve the patients’ ability to walk.
Wagner, F. B., Mignardot, J.-B., Goff-Mignardot, C. G. L., Demesmaeker, R., Komi, S., Capogrosso, M., … Courtine, G. (2018). Targeted neurotechnology restores walking in humans with spinal cord injury. Nature, 563(7729), 65. https://doi.org/10.1038/s41586-018-0649-2
Formento, E., Minassian, K., Wagner, F., Mignardot, J. B., Goff-Mignardot, C. G. L., Rowald, A., … Courtine, G. (2018). Electrical spinal cord stimulation must preserve proprioception to enable locomotion in humans with spinal cord injury. Nature Neuroscience, 1. https://doi.org/10.1038/s41593-018-0262-6