The Test of Mastication and Swallowing Solids and the Timed Water Swallow Test: Reliability, Associations, Age and Gender Effects, and Normative Data

Background: Quantitative measures can increase precision in describing swallowing function, improve interrater and test-retest reliability, and advance clinical decision-making. The Test of Mastication and Swallowing Solids (TOMASS) and the Timed Water Swallow Test (TWST) are functional tests for swallowing that provide quantitative results. Aims: To explore the relationship between TOMASS and TWST; evaluate test-retest and interrater reliability; explore age and gender effects; and gather normative data. Methods & Procedures: Healthy community dwelling participants (n = 298, [greater than or equal to] 20 years old) were recruited. Of those, 126 were included in the reliability study. Participants completed the TWST and TOMASS. Outcomes & Results: Associations between TWST and TOMASS measures were found using Pearson's correlation coefficient. Age was positively associated with an increase in the number of bites (n = 292, r = 0.15, p = 0.009), masticatory cycles (n = 291, r = 0.33, p < 0.0001) and duration (n = 292, r = 0.32, p < 0.0001) for the TOMASS. For the TWST, age was positively associated with an increase in duration (n = 296, r = 0.23, p < 0.0001), and negatively associated with volume (n = 296, r = -0.205, p < 0.0001), and swallowing capacity (n = 296, r = -0.24, p < 0.0001). Females required more bites, masticatory cycles, swallows and longer time than males in TOMASS. In TWST, females required more swallows, longer time, and had lower volume per swallow and reduced swallowing capacity than males. Intraclass correlation coefficient (ICC) revealed good test-retest reliability and moderate to excellent interrater reliability. Conclusions & Implications: This study provides support for the validity of the TOMASS and TWST. Reduced efficiency in one of the tests might indicate a need to evaluate performance in the other. Extended chewing time and increased number of masticatory cycles might be compensatory behaviours for reduced oral processing abilities that are motor, sensory and/or mechanical.