Page 211 - Functional impairment and cues for rehabilitation of head and neck cancer patients -

while subjective, patient-reported methods measure mostly swallowing perception, that is: perceived swallowing ability and functioning in daily life. What lacks in these two categories of measures is the swallowing capacity or transport capacity of the upper digestive tract (in grams per second), which is defined as the time needed to ingest boluses of different consistencies, as measured under standardized circumstances. Swallowing capacity can therefore be operationalized as the speed at which a person can eat and drink. Swallowing capacity is in that sense comparable with a measure like vital capacity for the lungs (in liters per second), although compared to this measure, it is influenced stronger by the patient’s ability to adapt to functional impairments, since swallowing is a complex action. We hypothesized that a method that measures eating and drinking speed under standardized circumstances would more accurately reflect the impact of swallowing function impairments on functioning in daily life. We therefore developed the Swallowing Performance Eating And Drinking (SPEAD)-test which measures the time needed to ingest three boluses of different consistencies. In the development and preliminary validation study reported in Chapter 3, we showed that the outcome of this easily manageable test was correlated with objective as well as with subjective swallowing measures, which supports its construct validity. Also, results of the study supported feasibility and showed good to excellent reliability. This indicates that the SPEAD-test could be valuable in clinical practice as well as for research purposes to evaluate the swallowing capacity.
In the present thesis, functional results were presented of a patient cohort more than ten years after chemoradiotherapy and preventive swallowing rehabilitation (Chapter 4) (4). Function appeared to be well maintained up until the ten-year plus follow-up assessment, which was not quite expected given the substantial prevalence of late-onset dysphagia, which can occur or progress years after initial HNC treatment due to neuropathy, continuing fibrosis, and non-use atrophy (6). Thus, the findings described in chapter 4 are suggestive of a positive influence of the preventive rehabilitation strategies applied in these patients, next to the positive contribution of improved radiotherapy techniques, such as IMRT and VMAT (7). Also, when considering the ‘use it or lose it’-principle, it is likely that training the muscles of the head and neck area that are relevant for swallowing and speaking, before, during, and after HNC treatment, positively affects functional outcomes (8). Therefore, although evidence is still scarce and many questions regarding optimal frequency, intensity (e.g., intensity during initial rehabilitation and benefit of continued use of exercises), time, and type (e.g., combination of exercises) of rehabilitation are still left unanswered, it is understandable why preventive rehabilitation protocols have emerged into clinical HNC care.
As a consequence of the biological comprehension of the effectiveness of preventive rehabilitation, and the positive results of clinical studies, including the one performed at our institute, implementation into clinical practice seemed warranted.To assess the clinical outcomes after implementation, we studied the results on swallowing, mouth opening, and voice/speech outcomes of patients with oropharyngeal cancer treated with (C)RT, obtained between the first full year of its implementation (2013) and 2018 (Chapter 5). Implementation of a new clinical approach takes time. Over the studied period, the percentage of eligible patients enrolled in
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Discussion
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