Wrist flexion/extension control in C5 and C4 quadriplegic subjects using functional neuromuscular stimulation

The authors investigated the feasibility of using functional neuromuscular stimulation (FNS) to control wrist angle in C5 tetraplegics. They measured the moments available from the wrist muscles, the moments produced at the wrist by the finger muscles during grasp, and the passive properties of the wrist joint. Furthermore, the authors evaluated three wrist position controllers. They found that the passive and finger muscle moments are significant compared with the moment produced by single wrist muscles and will affect the maximal range of wrist angle obtainable and the stability of the wrist during grasp. Feedback regulation would provide increase wrist stability in the presence of disturbances, with possibly less wrist muscle activation