Accommodation to changes in bolus viscosity in normal deglutition: A videofluoroscopic study

Videofluoroscopic swallow studies were performed on 60 normal adult volunte ers. Swallowing variables were measured during swallows of a 3-cm(3) paste bolus and a 3-mL liquid bolus and were compared to identify changes in swal low gesture displacement and timing, as well as changes in bolus movement t iming. The study revealed that some differences measured by videofluoroscop y appear to be the result of the inherent bolus characteristics, while othe rs likely represent changes in swallow gestures needed to accommodate varia tions in bolus viscosity. The overall timing of pharyngeal transit did not vary between bolus types. Oropharyngeal transit trended toward being faster for a liquid bolus with a concurrent early elevation of the aryepiglottic folds. The hyoid bone elevated at the same time, at the same rate, and to t he same extent irrespective of bolus viscosity. During a liquid bolus swall ow, the hyoid bone trended toward a more prolonged elevation, corresponding to prolonged pharyngoesophageal sphincter opening. The pharyngoesophageal sphincter. however, opened to a greater extent with a paste bolus.