Test of masticating and swallowing solids : sensitivity to Parkinson’s disease severity.
Thesis DisciplineCommunication Disorders
Degree GrantorUniversity of Canterbury
Degree NameMaster of Science
Objectives: The Test of Masticating and Swallowing Solids (TOMASS) has been proposed as a quantifiable assessment of swallowing efficiency that encompasses both oral and pharyngeal components of swallowing. This test may have clinical application as a dysphagia screening and treatment outcome measure. Reduced swallowing efficiency has been documented in patients with Parkinson’s disease (PD). The literature also suggests that severity of PD motor symptoms correlates with dysphagia severity. This study aimed to determine whether the TOMASS is a sensitive tool for identifying a decline in swallowing efficiency related to the presence and severity of PD. Comparison of performance on the TOMASS with a test that had already been validated in this population, the 150 ml Timed Water Swallowing Test (TWST), might also provide further insight in to the sensitivity of the TOMASS, it’s relationship with dysphagia, and application to the PD population. Participants: Forty participants with a diagnosis of PD were evenly recruited to two groups based on severity of PD motor symptoms: mild-moderate PD and advanced PD. Classification was based on Hoehn and Yahr scale PD severity scores that were assigned to PD participants after administration of the Movement Disorders Society – Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) part III – motor examination. Age and gender-matched controls for each group were also recruited. Method: Each participant completed the Eating Assessment Tool (EAT-10) survey. Participants then completed two trials of a 150 ml TWST and two trials of the TOMASS whilst being video recorded. The order in which these tests were presented was counterbalanced. Total time taken, number of bites, number of masticatory cycles, and number of swallows were recorded for solid food trials. Total time taken, number of swallows, and volume swallowed were recorded for fluid trials. To establish intra- and inter-rater reliability, 20% of the video-recordings were randomly selected and reviewed by the primary researcher and two final-year speech-language therapy (SLT) students. Results: High intra-rater reliability (ICC > 0.8) was achieved across all measures on the TOMASS and the TWST. Similarly, high inter-rater reliability (ICC > 0.8) was achieved across all measures on TWST and TOMASS except the number of swallows on the TOMASS, which had only moderate agreement (ICC=0.67). There were no significant differences in TOMASS measures between the mild-moderate PD and advanced PD groups. There was, however, a longer total time required for the mild-moderate PD group compared to the control group and a longer total time and an increased number of swallows, masticatory cycles, and bites in the advanced PD group compared to the control group on the TOMASS. There was a positive correlation between increasing PD severity as indicated by higher MDS-UPDRS scores and masticatory cycles. Positive correlations were found between TOMASS and TWST for total time and number of swallows. Conclusions: The TOMASS is a sensitive measure of reduced solid food swallowing efficiency caused by PD. The presence of PD rather than severity appears to have a stronger influence on reduced swallowing efficiency but PD severity does appear to play a role. Despite the differences in TOMASS variables between groups, the effect sizes were small, which reduces its clinical applicability. However, the sample of patients recruited in this study did not represent the severity of patients clinically presenting for swallowing evaluation and population bias can explain these small effect sizes. The number of masticatory cycles appears to be the most sensitive measure in response to changes to PD severity but it is unclear what impact dentition has on this measure. The TOMASS is a solid food correlate to the TWST, as expected, and there is a relationship between decreased efficiency in completing the TOMASS and the presence of dysphagia. Further research to validate the TOMASS is required before conclusions can be drawn around its clinical application.