By Allan Mai ‘20
Spinal cord injury continues to be a leading cause of paralysis in humans. Depending on the location of the injury, complete or partial paralysis can occur. Fortunately, we live in an age in which advanced neurotechnology such as epidural stimulation is being developed to reverse this condition. In this study, the University of Lausanne’s Dr. Fabien B. Wagner and his team used an implanted pulse generator to deliver trains of spatially selective stimulation to the lumbosacral spinal cord and coincided the timing with the intended movement. After just a few months, the participants regained voluntary control over formerly paralyzed muscle.
Epidural electrical stimulation (EES) utilizes the neuronal pathways that are spared from injury to improve the ability of the spinal cord to translate task-specific sensory information into the muscle activity that underlies standing and walking. Dr. Wagner’s research involved a wireless device that allows for real time control over EES signals to the spinal cord. Three males with a form of paralysis that prevented them from walking were recruited to participate in the study. In addition, a surgical procedure was developed to guide the precise placement of EES apparatus into the spinal cord. The researchers then used computational models to create simulations to identify the optimal electrode configurations. When personalized configurations had been developed for each participant, the devices were turned on. Each individual regained some voluntary control over their lower limbs; during a treadmill exercise, one participant was even able to walk a kilometer without exhaustion.
Despite its success, the experiment was not without problems. Continuous stimulation of the posterior roots via EES led the participants to report loss of proprioception; only spatiotemporal EES enabled effective restoration of motor function. While there remains much work to be done, EES remains one of the most promising forms of therapy that may see increased applications in clinical settings within the next few years.