Neuroprosthetics

Abstract

Neuroprostheses based on functional electrical stimulation (FES) are a means for compensation of lost motor functions such as grasping or walking. Many prerequisites need to be fulfilled for successful use of a neuroprosthesis, most importantly a low degree of lower motor neuron damage, an unrestricted passive joint motion, and a negligible spasticity. For improvement of the grasp function, neuroprostheses with different degrees of complexity and invasiveness exist. The systems available for routine clinical application have demonstrated functional benefits and improvement of the users' independence and quality of life. Hybrid neuroprostheses combining FES with orthoses hold promise for restoring completely lost upper extremity function. Novel user interfaces integrating biosignals from different sources are needed to make full use of their many degrees of freedom. Brain-computer interfaces are an emerging technology that may serve as a valuable adjunct to traditional interfaces. The main barrier for everyday use of lower extremity neuroprostheses solely based on FES is the occurrence of rapid muscle fatigue due to a nonphysiological spatial and temporal activation by FES. However, their combined use with semi-active gait orthoses or robotic exoskeletons promises to overcome some of the current limitations.