Electromyographic activity from human laryngeal, pharyngeal, and submentalmuscles during swallowing

The durations and temporal relationships of electromyographic activity from the submental complex, superior pharyngeal constrictor, cricopharyngeus, t hyroarytenoid, and interarytenoid muscles were examined during swallowing o f saliva and of 5- and 10-ml water boluses. Bipolar, hooked-wire electrodes were inserted into all muscles except for the submental complex, which was studied with bipolar surface electrodes. Eight healthy, normal, subjects p roduced five swallows of each of three bolus volumes for a total of 120 swa llows. The total duration of electromyographic activity during the pharynge al stage of the swallow did not alter with bolus condition; however, specif ic muscles did show a volume-dependent change in electromyograph duration a nd time of firing. Submental muscle activity was longest for saliva swallow s. The interarytenoid muscle showed a significant difference in duration be tween the saliva and 10-ml water bolus. Finally, the interval between the o nset of laryngeal muscle activity (thyroarytenoid, interarytenoid) and of p haryngeal muscle firing patterns (superior pharyngeal constrictor onset, cr icopharyngeus offset) decreased as bolus volume increased. The pattern of m uscle activity associated with the swallow showed a high level of intrasubj ect agreement; the presence of somewhat different patterns among subjects i ndicated a degree of population variance.