Effects of viscosity, taste, and bolus volume on swallowing apnea duration of normal adults

The effects of viscosity, taste, and nectar-thick liquid bolus volume on swallowing apnea duration (SAD) were examined. Twenty-two adults, comprised of 10 males and 12 females, participated. SAD was assessed via nasal airflow during swallow conditions of viscosity (thin liquid, thick liquid, and puree), taste (water, apple juice, lemon concentrate), and nectar-thick liquid bolus volumes (5, 10, 15, and 20 mL) across three trials. A significant main effect of nectar-thick liquid bolus volume was found (P < 0.05). Viscosity and taste were not significant. SAD increased with increases in bolus volume; however, neither changes in bolus viscosity nor changes in taste affected SAD. These findings indicate that since viscosity was not significant, the normative data previously published (by this PI) with 60 healthy adults stratified by age and gender can be utilized for comparison to disordered swallowing without regard to the bolus viscosity being used. EBM rating: D.