A preliminary study of action potential propagation in paretic muscle of stroke survivors

Individual motor unit action potential (MUAP) propagation along the muscle fibers was assessed in paretic muscle of stroke survivors. Single motor unit activity was recorded from the biceps brachii muscle on the paretic side of stroke survivors using a surface electrode array. Among the 15 clearly identified low-threshold motor units, six units showed little delay between MUAPs on different electrodes aligned along muscle fibers, resulting in abnormally high values of calculated propagation velocities, while clear action potential delay was observed for the other motor units. Several factors that possibly lead to this observation are discussed.