Page 84 - Functional impairment and cues for rehabilitation of head and neck cancer patients -

82
Chapter 3
very important parameter in most objective measures – does not always induce decreased swallowing performance in daily life. In contrast, the SPEAD-rate is an objective outcome measure that correlates well with the objective measures of function, and even better with subjective measures of perception. This is evidence that the SPEAD-test meets its intended purpose of measuring those aspects of swallowing capacity that are important for patients’ functioning. Moreover, the SPEAD-rate correlates well with the degree of dysphagia as rated by experienced SLPs at our institute. This suggests the SPEAD-rate contains most elements that SLPs take into account by assessing the degree of swallowing problems in clinical practice. As such, the SPEAD-rate can complement currently available measures for quantifying swallowing capacity and monitoring the effect of certain swallowing rehabilitation strategies, both in research as well as in daily clinical practice.
In the development of the SPEAD-test we made choices related to the amount and manner of intake and the primary outcome of the test. The amount of the consistencies to be ingested by the participants was based on the WST and TOMASS. In our experience, the chosen amounts, 100 mL thin and thick liquid and the cracker is easy for participants with no swallowing impairment and can be difficult for patients with swallowing impairment, influencing the SPEAD-rate. Thus, we expected these amounts to provide sufficient variation for reliably assessing swallowing capacity.
Secondly, because initially we expected that participants would need a spoon to ingest thick liquid, we offered them this option. However, as the study progressed, it appeared that thick liquid could be ingested without a spoon, regardless degree of dysphagia. Therefore, we expect that in fact the vast majority of people will be able to perform the test without a spoon. As such, offering the option to use a spoon may introduce unnecessary variation in test administration. In a post-hoc analysis, we evaluated reliability and validity when participants who used a spoon were excluded. These results were comparable to those of the complete sample. Therefore, we recommend to perform the test without a spoon in clinical practice.
Thirdly, in the current study, all participants were observed from the front while measuring the results of the SPEAD-test. Although reliability results were good to excellent, observing the participants from the side might make it even easier to observe laryngeal movement.
Fourthly, the mean ingestion speed of all three consistencies (SPEAD-rate), was selected as the primary outcome of the SPEAD-test. This was chosen because ingestion speed is expected to better reflect swallowing capacity than swallow volume of number of chews alone. Also, it is not feasible to measure both duration and number of swallows or chews simultaneously when measuring the duration with a stopwatch. However, in clinical practice, video recording the participant taking the test is advised, partly because in case aspiration occurs or a patient needs assistance for other reasons the test is recorded and assessment of SPEAD-rate can be performed afterwards.