Quantifying Post-Swallow Residue in Healthy Aging

Abstract

Purpose: Reports are mixed on whether post-swallow residue increases with age. This question was investigated using a quantitative measure of residue in a large cohort of healthy adults. It was hypothesized that post-swallow residue would differ between younger and older healthy adults, and significantly increase in individuals ≥ 80 years. Method: In this observational study, 275 healthy volunteers aged 18-99 years underwent videofluoroscopic swallow studies. Post-swallow residue was quantified using the Bolus Clearance Ratio (BCR) for a 20-ml thin liquid barium bolus and 3-cm3 barium paste bolus. Number of swallows required per bolus and aspiration were also determined as additional markers of swallow efficiency and safety. Results: Most BCR values were low, < 0.05 (< 5% of the bolus) for 78% of 20 ml and 66% of paste swallows. BCR values were significantly larger in healthy older adults, although, clinically, the differences are arguably minimal (differences in mean BCR values between age groups: 20 ml: 0.01 [1%]; paste: 0.03 [3%]). For 20 ml, 56% of adults ≥ 80 years performed multiple swallows (oral residue and dose metering) versus 9% of adults 18-39 years. One aspiration event was observed. Conclusions: Post-swallow residue was slightly increased in older adults; many individuals ≥ 80 years performed more than one swallow per bolus to achieve this similar level of clearance. This suggests a reduction in swallow efficiency with age without compromising swallow safety. Post-swallow residue that poses a risk of airway invasion should be considered a sign of swallowing dysfunction, not healthy aging.