Abstract
Orbicularis oris superior and inferior (OOS, OOI), levator anguli oris (LAO), depressor anguli oris (DAO), and mentalis (Ment) are considered as typical perioral muscles that contribute to the occurrence of force or pressure in or around lip aperture. This study presents the experimental and analytical results that show the correlationships between electrical muscle activities of these muscles and such mechanical parameters on bilabial closing force, puckering force, POM value and so forth. Besides zeor-lag correlation coefficients between rectified and low-pass filtered SEMG signals of LAO and DAO was constantly greater than other muscle combinations sometimes including that of OOS and OOI, which are believed to be the most closely correlated motors in common for lip movement. Consequently we succeeded to prove the great importance of the coordination between LAO and DAO to produce bilabial consonants.
