Variation in temporal measures of swallowing: sex and volume effects

Temporal measures of healthy swallowing appear to be variably sensitive to bolus and participant factors based on a recent meta-analysis of studies in the deglutition literature. In this carefully controlled study of healthy young volunteers, balanced for sex and height, we sought to understand the influence of bolus volume and participant sex on the three durations and three intervals most frequently reported in the deglutition literature. Three boluses per target volume (5, 10, and 20 ml) were repeated for each participant (n = 20, 10 male) using a spontaneous swallow paradigm in lateral view videofluoroscopy. None of the temporal durations or intervals was found to be correlated with participant height above an a priori cutoff point of r ≥ 0.3. Further, none of the temporal durations or intervals varied significantly by participant sex. Bolus volume significantly impacted upper esophageal sphincter (UES) opening duration, laryngeal closure duration, the laryngeal closure-to-UES opening interval, and the pharyngeal transit time interval, but not hyoid movement duration or the stage transition duration interval. When participants are sampled in such a manner as to represent the range of height reported to be typical for both sexes in the population, sex does not significantly influence temporal measures of swallowing.