Spatiotemporal Transcutaneous Spinal Cord Stimulation and Analysis of Muscle Recruitment During Gait

Spinal cord injury leads to reduced or even absent locomotor capabilities. Transcutaneous spinal cord stimulation (tSCS) represents a method to accelerate the recovery process, particularly in daily clinical applications. A spatiotemporal protocol for the delivery of tSCS is presented to provide meaningful insights into the muscular activity of ten healthy subjects. We employed an external pulse generator to deliver real-time continuous trains of stimulation to the lumbosacral region of the spinal cord. The stimulation is applied in coincidence with the detection of the subphases of gait, achieved through the processing of angular velocity data from two Inertial Measurement Units (IMUs) placed on the subjects' shanks. Specific regions of the spinal cord are targeted according to the specific subphase of each leg. Currently, these applications are limited by the technique's restricted selectivity. Investigations in healthy subjects represent the first step towards clinical applications. We believe that this stimulation protocol could enable maximal rostrocaudal and mediolateral selectivity to achieve muscle-specific activations, paving the way for a whole new range of movements in rehabilitative applications of tSCS.