Current status and future prospects for upper and lower extremity motor system neuroprostheses.

This paper reviews the current state of the art and identifies the major challenges facing the future development and clinical application of neuroprostheses to provide limb movement. It gives insight into the current status of functional electrical stimulation (FES) for motor control, identifies problems, and proposes possible directions of development in cervical cord injury, thoracic spinal cord injury, and stroke. For upper extremity function, existing clinical applications are covered, major problems are identified, and possible future trends are highlighted. The discussion on lower extremity applications describes current and possible future solutions of the major impediments to the development of FES systems for individuals with paraplegia after spinal cord injury and surface and implantable setups for stroke survivors with hemiplegia. Particular attention is given to sensor issues and requirements for walking with FES after stroke.