A SIMULATION STUDY ON NEUROMUSCULAR FACTORS AFFECTING CONSECUTIVE MOTOR UNIT ACTION POTENTIAL WAVESHAPE

Abstract

Quantification of consecutive motor unit potential (MUP) is used to diagnose and monitor the progress of neuromuscular pathologies in clinical applications. In this study, a detailed motor unit simulation was conducted to reveal and understand the factors affecting MUPs. Using a volume conductor model and real muscle parameters, normal and pathologic MUPs were created. The shape changes observed in consecutive MUPs, called jiggle, are calculated with a quantification method. Increased jitter duration and re-innervation percentage commonly observed during motor unit loss increase the jiggle value proportionally. Moreover, increasing fiber density changing different regions of a muscle bundle decreases the jiggle value. The blocking phenomena generally observed in re-innervated fibers affects the jiggle value similar to jitter duration. But, higher blocking levels (50%) of re-innervated motor fiber do not have an effect on jiggle value as lower levels of blocking (20%). In conclusion, simulation of pathological MUPs showed that it is useful for clinicians to understand the progress of a neuromuscular pathology and the factors affecting consecutive MUP wave shape.