Three paralyzed men who sustained cervical spinal cord injuries many years ago are now able to walk with the aid of crutches or a walker thanks to new rehabilitation protocols, which combine targeted electrical stimulation of the lumbar spinal cord and weight-assisted therapy.
This latest study, called STImulation Movement Overground (STIMO), was led by researchers at Ecole Polytechnique Fédérale de Lausanne (EPFL) and Lausanne University Hospital (both Switzerland). The results have been published in Nature and Nature Neuroscience.
STIMO establishes a new therapeutic framework to improve recovery from spinal cord injury. All patients involved in the study recovered voluntary control of leg muscles that had been paralyzed for many years. The researchers report that, unlike the findings of two independent studies published recently in the USA on a similar concept, neurological function was shown to persist beyond training sessions even when the electrical stimulation was turned off.
“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,” explained Grégoire Courtine (EPFL).
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“All patients could walk using body weight support within 1 week. I knew immediately that we were on the right path,” added Jocelyne Bloch (Lausanne University Hospital), who surgically placed the implant in the patients.
“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,” commented Courtine.
Bloch explained that in their method, they implanted an array of electrodes over the spinal cord, which allowed them to target individual muscle groups in the legs. “Selected configurations of our electrodes are activating specific regions of the spinal cord, mimicking the signals that the brain would deliver to produce walking,” she added.
All three study participants were reported to walk with body-weight support after only 1 week of calibration, and voluntary muscle control improved tremendously within 5 months of training.
During rehabilitation sessions, the three participants were able to walk hands-free over more than 1 km with the help of targeted electrical stimulation and an intelligent bodyweight-support system. Additionally, they exhibited no leg-muscle fatigue, and so there was no deterioration in stepping quality. These longer, high-intensity training sessions proved crucial for triggering activity-dependent plasticity, which leads to improved motor function even when the electrical stimulation is turned off.
GTX medical (Lausanne, Switzerland), a startup co-funded by Courtine and Bloch, will use these findings to develop tailored neurotechnology with the aim to turn this rehabilitation paradigm into a treatment available at hospitals and clinics everywhere.
Courtine concluded that: “We are building next-generation neurotechnology that will also be tested very early post-injury, when the potential for recovery is high and the neuromuscular system has not yet undergone the atrophy that follows chronic paralysis. Our goal is to develop a widely accessible treatment.”
Sources: Wagner FB, Mignardot J-B, Le Goff-Mignardot CG et al. Targeted neurotechnology restores walking in humans with spinal cord injury. Nature doi:10.1038/s41586-018-0649-2 (2018) (Epub ahead of print); https://actu.epfl.ch/news/breakthrough-neurotechnology-for-treating-paralysi/