Simultaneous contraction mechanics and coordination of perioral muscles

Abstract

Orbicularis oris superior (OOS), orbicularis oris inferior (OOI), levalor anguli oris (LAO), depressor anguli oris (DAO), and mentalis (Ment) are considered as typical perioral muscles that contribute to the force and pressure occurence in and around lip aperture. This study presents the experimental and analytical results that show correlationships between electrical muscle activities and mechanical parameters on bilabial closing force, puckering force, POM (perioral muscle) value and so forth. Besides, zero-lag correlation coefficients between rectified and smoothed SEMG signals of LAO and DAO was constantly higher than other muscle combinations including OOS-OOI combination considered to be most closely related with lip movement, Among lip tasks, prominently high correlation between LAO and DAO was shown when subjects tried to close their lip bilabially at principally distal part. Consequently authors succeeded to prove the great importance of the coordination between LAO and DAO for producing bilabial consonants, drinking and eating, pooling saliva in oral cavity, and others, while the applicability of POM meter to myofunctional therapy is obscured.