Restoration of Standing and Walking With ISMS in Humans

Spinal cord neural circuitry exists in the lumbar enlargement that makes it possible to stand and create synergistic, rhythmic stepping activity in the lower limbs. In the past 20 years, clinicians have tried to reengage such these circuits for standing and walking in the lower spinal cord of paralyzed humans through novel paradigms of physical therapy, pharmacological stimulation of the spinal cord, or recently - epidural stimulation of the spinal cord. Although standing and stepping with these maneuvers are rudimentary at best, these human studies offer promise to restore controlled, lower extremity movement to the spinal cord injured (SCI) individual. Evidence from animal data suggests that more focal activation of intraspinal circuitry (IntraSpinal Micro-Stimulation - ISMS) would produce more fatigue resistant, natural standing and stepping activity in humans. To date, there has been no direct confirmation of such circuitry in the spinal cord of bipedal humans who have been paralyzed. Furthermore, mapping of such circuitry would provide the basis of a novel intraspinal neuroprosthetic that should be able to restore control of standing or walking in a manner that is much more physiologically normal and tolerable than by stimulating each individual muscle group. Proof of the existence of these spinal circuits in man, and the ability to activate and control these circuits by first mapping the spinal cord is the basis of this proposal.