Initiation and duration of laryngeal closure during the pharyngeal swallow in post-stroke patients.
As a bolus enters the pharynx during the swallow, the airway is protected by laryngeal closure, a process characterized by approximation of the vocal folds plus approximation of the arytenoid cartilages to the base of the epiglottis. The purpose of this study was to measure initiation of laryngeal closure (ILC) and laryngeal closure duration (LCD) in three groups of subjects: (1) ten stroke patients who aspirated before and during the swallow (aspirators), (2) ten stroke patients who did not aspirate (nonaspirators), and (3) ten normal control subjects. Means and standard deviations of ILC and LCD were analyzed for both 5-ml and 10-ml thin-liquid boluses using a 100-ms timer during subsequent analysis of videofluoroscopic swallowing examinations. There were significant differences between aspirators and control subjects for both ILC and LCD, and significant differences between aspirators and nonaspirators for ILC. There were no significant differences between aspirators and nonaspirators for LCD. Both delayed ILC and reduced LCD were associated with post-stroke aspiration. Delayed ILC is a significant indicator of overall risk of aspiration. Clinical implications for these findings are discussed.