Timing of glottic closure during normal swallow

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Abstract
Background. The purpose of this study was to determine the temporal characteristics and patterns of glottic closure during normal swallow using concurrent videofluoroscopy and videoendoscopy. Methods. Three swallows each of four bolus types were examined in eight healthy volunteers with the endoscope in two positions: at the level of the uvula and at the laryngeal vestibule. Data analysis compared: (1) temporal relationships between laryngeal behaviors and oropharyngeal swallow events and (2) airway conditions at the time of key oropharyngeal events. Results. Although arytenoid adduction and subsequent arytenoid contact occurred as one of the initial events during swallow, the timing of these events was highly variable. On the other hand, true vocal cord (TVC) closure occurred mainly after the onset of laryngeal elevation, and it was affected by bolus volume. Conclusions. In normal swallow, arytenoid closure did not always mean complete TVC closure, and complete TVC closure might be accomplished during the process of laryngeal elevation and arytenoid tilting.