How much is too much? Effect of volume on water-swallowing test

Introduction: Water-swallowing test (WST) is a simple, economical bedside screening test practiced for early identification of risk for dysphagia (or swallowing impairment). However, there is no consensus on the right test quantity to assess swallowing ability by WST. Aim of the Study: The aim of the present study was to establish the right quantity of water for WST sufficient to assess sequential swallowing in healthy adults albeit avoiding larger quantity of thin liquids. Subjects and Methods: Thirty healthy young adults (HYA) (20–40 years) and thirty healthy middle-aged adults (HMA) (41–60 years) were enrolled by nonrandom convenient sampling. Four quantities (50, 90, 100, and 150 ml) of room temperature water was gauzed by a measuring cup and randomly presented to the participants to swallow in their natural pace. As per the test standard, volume/swallow (V/S), time/swallow (T/S), and swallow capacity (SC) indices were derived and subjected to further statistical analysis. Results: The results of the study suggested statistically significant increased V/S and SC in a lesser T/S among HYA compared to HMA, and the difference was at P < 0.05. The results also revealed 150 and 50 ml to have statistically significant highest and lowest SC, respectively, at P < 0.05. Pearson's correlation index suggested a positive correlation across swallowing indices between the four test volumes of water. Conclusion: The state of evidence suggests better swallowing performance in HYA, and also, there exists a direct relationship between the quantity of water and indices of WST. The advisory is to use the least of the four test quantity of thin liquids for the WST.