Comparison of Transcutaneous and Epidural Spinal Stimulation for Improving Function

Incomplete spinal cord injuries (SCI) are the most frequent neurologic category, comprising 66.7% of all SCI cases. People with incomplete SCI may retain some ability to move the legs and therefore the capacity to regain walking. Studies that show functional improvement in locomotion via electrical stimulation of lumbosacral circuits suggest that the underlying mechanisms are neuromodulation of lumbosacral spinal cord automaticity and sensory feedback. Both epidural and transcutaneous spinal stimulation are demonstrating exciting potential to improve limb function for people after chronic SCI. Available treatment options for SCI are less than satisfactory and most often do not achieve full restoration of function. Recent experimental results suggest an exciting new approach of using electrical spinal stimulation to enable users to regain control of their weak or paralyzed muscles. Using surgically-implanted electrodes, epidural stimulation results in remarkable improvements of lower extremity function as well as autonomic functions such as bladder function and sexual function. In addition to epidural stimulation, over only the last few years a novel strategy of skin surface electrical spinal stimulation has also demonstrated exciting potential for improving walking function. Using a high-frequency stimulation pulse, current can pass through the skin without discomfort and activate the spinal cord; this results in patterned stepping movements for people without SCI and improved lower extremity function following SCI. This study will directly compare skin-surface transcutaneous stimulation with implanted epidural stimulation for improving lower extremity function.