Chapter 19 - Designing a Neural Interface System to Restore Mobility

Abstract

This chapter focuses on neural interface (NI) systems that are used to restore communication and mobility in persons with impaired mobility. The neuromodulation field has created very successful neural interface technologies that are designed to restore lost or disordered functions of the nervous system. NI systems that can sense neural activity are integrally linked to neuromodulation systems. All NI systems, including both direct and surrogate systems, face a similar set of design issues, which include sense, decode, and control. The goal of the first two steps is to record and transmit a signal that provides useful commands, whereas the control step uses the command signal to effect some desired action through an AT or biological system. For sensing, it is necessary to define the type of signal desired, the source or location(s) of that signal in the nervous system, and the type of sensor that is needed to reliably detect that signal over time. Decoding is based on algorithms that attempt to extract information related to desired movement from neural signals, and it may also perform functions that make up for parts of the nervous system that no longer interact with the neural commands. The control function provides an effective coupling of commands to an AT or to muscles, each of which may make special demands of the control signal. Sensors are the requisite neural–physical interface to obtain neural signals and they have a range of designs that are influenced by the types of signals desired, the duration of recordings, and the complexity of obtaining these signals. A complete NI system is one that integrates the sensor, decoder, and controlled device into a complete system that returns control and independence in a reliable manner, without encumbering other functions.