Post-stroke dysphagia: clinical and radiological outcomes and efficacy

Upwards of 50% of stroke survivors show symptoms of swallowing impairment (dysphagia) post-stroke. Dysphagia is clinically important as it results in poorer outcomes and affects quality of life. Despite this, there are few proven treatments. In addition, the act of swallowing is intricate and complex and may be best measured using multiple outcomes. This thesis had three principal aims: firstly, to evaluate the current evidence base for swallowing therapy by updating the Cochrane review into swallowing therapy in acute and subacute stroke. Secondly, to evaluate the use of multiple measures of swallowing (timing and clearance measures) to detect change following a swallowing treatment (Pharyngeal Electrical Stimulation - PES) as opposed to only using a single measure of safety, the Penetration Aspiration Scale (PAS). This was done using retrospective data analysis of videofluoroscopic data from the Swallowing Treatment using Electrical Pharyngeal Stimulation Trial (STEPS) which had already been evaluated for safety using only the PAS. And thirdly, to expand the range of outcome measures available for measuring dysphagia by validating the dysphagia severity rating scale (DSRS), a clinical outcome measure currently in use but not yet validated. The results of this thesis have confirmed three main findings with regards to clinical and radiological outcomes post-stroke. Firstly, the Cochrane review has highlighted that currently, swallowing therapy does show some positive benefits but this is based on evidence of variable quality. Recommendations for conducting more robust trials in the future are discussed. Secondly, with regards to using multiple measures, videofluoroscopic data analysis revealed that additional measures of timing and clearance did not result in the identification of any improvements that may have gone undetected using safety measures alone (PAS). However, final numbers were reduced due to data quality and lower frame rate acquisition and hence it would be premature to conclude that using the PAS alone is sufficient when measuring swallowing outcomes post-stroke. Finally, with regards to measuring dysphagia severity post-stroke, the DSRS was validated. The results showed that it appears to be a valid tool for grading the severity of swallowing impairment in patients with post-stroke dysphagia and is appropriate for use in clinical research and clinical service delivery