Change in Levator Veli Palatini Muscle Activity in Relation to Swallowing Volume During the Transition from the Oral Phase to Pharyngeal Phase

The aim of this study was to examine whether the levator veli palatini (LVP) muscle might be involved in the regulation of velopharyngeal function during the transition between the oral and pharyngeal phases during swallowing, and to examine whether LVP muscle activity could be regulated in relation to the volume of swallowing. Eight normal adults participated in this study. Smoothed EMG signals of the LVP muscle were collected. At the same time, palatoglossus muscle activity was also monitored. Each subject swallowed water at five different volumes: 12.5%, 25%, 50%, 100%, and 150 (or 200) % of the optimum volume for swallowing, which was individually determined for each subject. LVP muscle activity was positively correlated with changes in swallowing volume. The LVP muscle was involved in the regulation of swallowing during the transition from the oral to pharyngeal phases.This research was supported by a Grant-in-Aid for Scientific Research [(B) No. 16300237, (C) No. 16639020, No.15592048, No.17592021) from the Ministry of Education, Science, Sports and Culture, Japan.