Electromyographic response of the labial muscles during normal liquid swallows using a spoon, a straw, and a cup

In this investigation, surface electromyographic (EMG) recordings were used to make qualitative and quantitative analyses of labial muscle activity during three swallowing tasks, incorporating the use of various drinking implements. EMG was recorded from four quadrants of the perioral region and from the submental muscle complex in 11 normal adult females. Swallowing tasks included liquid extraction from a spoon, a straw, and a cup and posterior bolus propulsion of a 5 ml, thin liquid. Average EMG values obtained during a maximal lip compression task were used to normalize labial muscle responses for each subject thus allowing between-subject comparisons. Variable activity patterns were noted in the perioral muscles once the lips were contacted by a drinking implement. Subjects used a greater percentage of maximal labial muscle activity to remove liquid from an implement than to swallow the liquid. A greater level of EMG was recorded in the lips during straw usage as compared with spoon or cup usage. Significant intrasubject and intersubject variability in labial function occurred during liquid removal using a drinking implement and during the oral swallow in these normal subjects.