Compact Neural Interface Using a Single Multichannel Cuff Electrode for a Functional Neuromuscular Stimulation System

Cuff electrodes have been introduced into functional neuromuscular stimulation systems to either obtain neural signals or elicit limb movements. Multiple electrodes must be implanted to construct a feedback control loop, including one electrode for acquisition and another for stimulation. Existing approaches require too much space inside the body and a complicated surgical procedure. This paper proposes a novel neural interface method that uses a single cuff electrode with multichannel capability to simultaneously acquire multichannel recordings and induce electrical stimulation at the proximal nerve trunk of the sciatic nerve. Recordings and stimulation are conducted in a time-shared manner using a path controller. Using the proposed method, joint positions are estimated from multichannel recorded neural signals during electrical stimulation as neural signals are continuously recorded. In addition, the proposed system is shown to be suitable for controlling joint position. The proposed neural interface method overcomes the spatial limitations of electrode implantation and thus offers a new approach to developing compact neural interface systems.