ORAL AND LARYNGEAL MUSCLE COORDINATION DURING SWALLOWING

The objective of this experiment was to determine the relative contrib utions and patterns of activity of different muscles involved during t he oral phase of swallowing. Electromyographic (EMG) signals were reco rded from the orbicularis oris inferior, masseter, palatal elevator, a nterior and posterior genioglossus, mylohyoid, anterior belly of the d igastric, and vocalis muscles of 12 normal adult subjects. Each subjec t swallowed 15 mL of water, under normal and bite block conditions, 15 to 20 times. The integrated EMG signals for each subject's swallows w ere ensemble averaged. The results of the analyses showed that swallow ing function varies from individual to individual in terms of the spec ific muscles used and how the various muscle activity patterns are coo rdinated. These results suggest that swallowing is a highly complex ad aptive motor activity which probably relies more on higher-level contr ol mechanisms than previously believed.