Restoring movement after neurological disorders using functional neuromuscular stimulation

Neuroprostheses are systems that use artificial electrical stimulation of paralyzed nerves to restore function. Functional neuromuscular stimulation (FNS) can be used to restore function to individuals with paralysis resulting from a variety of neurological disorders, including spinal cord injury and stroke. This paper provides a sampling of the applications of neuroprostheses that have been made by investigators in the Cleveland FES Center to restore upper and lower extremity function following spinal cord injury. The challenges faced when attempting to apply standard control systems techniques to a multijoint, nonlinear, nonstationary, and sluggish plant (i.e., a paralyzed human limb) are discussed. Current methods of controlling FNS are presented and novel methods of controlling FNS, including measurement of voluntary muscle activity and body-mounted sensors, are reviewed.