Synthesis of hand grasp using functional neuromuscular stimulation

A functional neuromuscular stimulation system developed to provide grasp-release functions in quadriplegic individuals is discussed. A single command input from the subject controls the stimulus levels to a number of electrodes, thus simultaneously activating several muscles. A method for synthesizing the command input to stimulus output relationship has been developed. The first step involves electrode profiling, which is a method for characterizing the output of an individual electrode/muscle combination. The electrodes are then grouped according to function, and a set of rule-based procedures is used to synthesize the basic grasp parameters. Results demonstrating the output from lateral and palmar grasps developed by this method are presented. The method has successfully resulted in grasping patterns that can be utilized functionally. Limitations of the method and future improvements are discussed.<>