Restorative Neuromodulation for Lower Extremity Functions

Spinal cord is composed of specialized neural networks, capable of executing different functions. Although the command for lower-limb functions such as standing and walking is primarily delivered from the brain, it was found that the spinal cord circuits not only execute it but also maintain the task and control the dynamics with proper feedback mechanisms with it's reflex circuitry. Simple bipedal standing and walking requires spatiotemporal coordination of muscles, limb joints, balance etc., their adaptation and control in gravity. For human, these physiological activities are well choreographed by sets of neural networks. In combination with afferent proprioceptive inputs, these network circuits work with the motor periphery to generate a series of motor acts during each task. Normally, the activity of these spinal networks are regulated supraspinally and by peripheral sensory inputs. In case of the loss of supraspinal inputs, resultant of a Stroke or spinal cord injury (SCI), motor tasks maybe enabled by directly activating these specialized spinal cord networks via external stimuli. Recent studies have demonstrated that neuromodulation via spinal cord stimulation can effectively restore lower-extremity functions in patients with chronic neurological injuries.

Traumatic injury to the central nervous system (CNS) such as SCI is devastating events leaving patients with impairment of motor, sensory and autonomic functions. Mainstay for the treatment is still limited to rehabilitation by physical therapy and training. In few patients, however, neuroplasticity and repair mechanisms are considered to contribute to recovery of paresis in the acute stage of the injury and stops in the chronic stage. But, recent groundbreaking studies have shown that the recovery can be further amplified in the chronic stage by the novel treatment of trans-spinal electrical stimulation. However, the rehabilitation related to this recovery is not very significant, and thus it is a challenge to be convinced with the efficacy of this new therapy. A combination therapy of trans-spinal electrical stimulation along with body-weight would promote better recovery and benefit the patients more. The current study will further assist the researchers to design such combinational therapeutic intervention for neurologically impaired patients to stimulate to walk again. Successful translation of this novel technology would facilitate the paraplegic community to become more healthy, independent and happy.

Inclusion criteria

• Be at least one year post-injury and not dependent on ventilation support
• Lower-extremity paralyzed and half of key muscles below neurological level having a motor score of less than 2/5
• Female subjects must be on standard contraception method and must not be pregnant throughout the study
• Segmental reflexes are functional below the lesion
• Ability to exercises 1-2 hours per day and commit for 1 year training program

Exclusion criteria

• Cardiopulmonary disease or dysfunction, high blood pressure or other condition which contraindicate participation in lower extremity rehabilitation exercise
• Received of Botox injections in the prior 6 months
• Weakened bone, unhealed fracture, contracture, pressure sore, or infection that might interfere with the exercise
• Thoracic or lumbar fusion with any metal which may interfere with electric currents
• Other electronic implants such as cardiac pacemaker, defibrillator, shunt, stent etc.
• Currently receiving treatments for pain management or spasticity or depression.