Functional electrical stimulation (FES) is the use of low level current to restore function in the case of nervous system damage or dysfunction. Neural prostheses that utilize FES require the safe delivery of electrical current to the tissue to elicit or inhibit the activity of a nerve. Electrodes that deliver the electrical current must provide adequate charge carrying capacity that is delivered precisely to the desired region, and must perform reliably and repeatability in the body for decades under conditions of repeated motion and under loading conditions that are often unknown. These requirements, coupled with the body environment create a significant design challenge to the engineering team.

Electrodes and leads for restoration of movement have now been in the body for decades, and sufficient data is available to report both performance characteristics and the survival statistics. This information demonstrates the viability of the implanted components of the neural prostheses that are becoming more widely deployed into clinical practice.