In order to reanimate a paralyzed limb to produce clinically useful movements, three functions must be provided: 1) Electrical stimulators to cause muscles to contract; 2) A controller to coordinate the stimulation; and 3) Sensors of command and feedback signals from the patient to the controller. The investigators have recently completed development and preclinical testing of a novel stimulation technology that permits large numbers of individual muscles to be precisely controlled by injectable, wireless microstimulators that receive power and data by RF transmission from an external controller. They propose to extend that technology by incorporating and testing various types of sensors in similar injectable modules. These will use a novel, compatible system for RF back-telemetry to send signals out of the limb for command and feedback purposes. Their immediate goal is a family of generic """"""""BIONs"""""""" (bionic neurons)-that can be configured flexibly to serve a wide range of Functional Electrical Stimulation (FES) applications. The investigators have selected the following basic sensing modalities: 1) Low-level bioelectric signal recording such as electromyography, to monitor (the) level of electrical recruitment (M-waves) and spontaneous activity from muscles with some remaining voluntary control (useful as myoelectric commands for prostheses);and 2) Triangulation of relative position between devices, to be used for determining limb posture Acceleration and inclination (vs. gravity), using microelectromachined silicon (MEMS) sensor technology. The research will proceed in overlapping stages, the first of which is already underway in pilot work: 1) Design, build and test the basic circuit functions for low-level, low-power signal detection, digitization and telemetric transmission; 2) Design, build and test specialized MEMS sensors; 3) Build complete injectable BIONs with sensing and back-telemetry capabilities; 4) Perform preclinical tests of sensor BIONs for biocompatibility; 5) Test sensing and telemetry functions in vitro with artificially-generated inputs; and 6) Test sensing and telemetry functions in alert, behaving animals.
