Swallowing physiology of sequential straw drinking

The goal of this study was to examine deglutitive physiology during sequent ial straw drinking in healthy young adults (n = 15) to learn how sequential swallowing differs from single swallows. The physiology of single swallows has been studied extensively in healthy adults and in adults with a variet y of debilitating conditions, but the physiology of sequential swallows has not been studied adequately. Videofluoroscopic analysis revealed three dis tinct patterns of hyolaryngeal complex (HLC) movement during sequential str aw swallows: opening of the laryngeal vestibule after each swallow (Type I, 53%), continued vestibule closure after each swallow (Type II, 27%), and i nterchangeable vestibule opening and closing during the swallow sequence (M ixed, 20%). Unlike discrete swallowing, the onset of the pharyngeal swallow occurred when the bolus was inferior to the valleculae in the majority of subjects and was significantly associated with HLC movement pattern. The le ading bolus edge was inferior to the valleculae at swallow onset for Type I I movement patterns. For Type I movement patterns, bolus position at swallo w onset was randomly distributed between three anatomical positions: superi or to the valleculae, at the level of the valleculae, and inferior to the v alleculae. Preswallow pharyngeal bolus accumulation, which is common during mastication, was evident and significantly associated with the HLC pattern of opened laryngeal vestibule after each swallow. These data suggest that in healthy young adults, sequential swallows differ physiologically from di screte swallows and indicate substantial variability in deglutitive biomech anics.