Characterisation of dysphagia in diverse populations using pharyngeal high-resolution manometry with impedance

Author: Mistyka Schar

Schar, Mistyka, 2022 Characterisation of dysphagia in diverse populations using pharyngeal high-resolution manometry with impedance, Flinders University, College of Medicine and Public Health

Terms of Use: This electronic version is (or will be) made publicly available by Flinders University in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. You may use this material for uses permitted under the Copyright Act 1968. If you are the owner of any included third party copyright material and/or you believe that any material has been made available without permission of the copyright owner please contact with the details.


Oropharyngeal swallowing difficulty (dysphagia) is a symptom resulting from impairment or disorder affecting the swallowing mechanism. The reported prevalence of dysphagia varies but in some patient groups can reach as high as 50%. Dysphagia is an important health issue as it can negatively impact quality of life and is associated with malnutrition, dehydration and aspiration pneumonia, contributing to increased health care utilization and cost. Videofluoroscopy swallowing study (VFSS) is considered the current gold-standard of swallow assessment, however this method has no universally accepted set of quantitative measures resulting in variability in interpretation and subsequent treatment planning. Pharyngeal highresolution manometry with impedance (P-HRM-I) provides precise and quantitative measures of pharyngeal and upper oesophageal sphincter (UOS) pressures integrated with bolus transit.

Unlike other swallowing assessment methods, P-HRM-I can identify and localise alterations in the swallowing mechanism and determine the underlying pathophysiological breakdown leading to dysphagia. This thesis endeavours to expand our understanding of the biomechanical swallowing patterns across a range of homogenous cohorts and following interventional procedures, providing novel findings that characterise dysphagia in these cohorts.

The following P-HRM-I swallowing assessments were conducted in four homogenous cohorts: obstructive sleep apnoea (OSA; n=19), post- modified uvulopalatopharyngoplasty with/without coblation channelling of the tongue (mUPPP+/-CCT) surgery for OSA (n=21), critically ill postextubation and/or decannulation (n=19), and post-Head and Neck Cancer treatment (HNC; n=14); and as an interventional outcome measure in two cohorts: pre- and post- mUPPP+CCT surgery for OSA (n=10) and pre- and post-tongue base augmentation following HNC treatment (n=6). P-HRM-I Core and Additional measures were reported consistent with international recommendations.

Novel and distinct biomechanical swallowing patterns were identified in the cohort studies, including: (1) altered UOS function with increased velopharyngeal contractile pressures in the OSA and post-mUPPP+/-CCT cohorts, (2) altered UOS function and increased bolus presence time in the critically ill following extubation and/or decannulation cohort, and (3) reduced pharyngeal contractile pressures with or without UOS dysfunction in the post-HNC treatment cohort; and in the interventional studies: (4) unchanged velopharyngeal contractile pressures, reduced meso- and hypo-pharyngeal pressures, and reduced UOS relaxation pressures postmUPPP+CCT surgery for OSA, and (5) no significant biomechanical changes following tongue xxi xxii base augmentation. However, subtle changes of improved UOS opening and relaxation were observed and hypothesised to indicate more efficient pharyngeal bolus transit.

The utilisation of P-HRM-I for swallowing assessment in the research setting has increased in recent years, albeit with inconsistencies in reported outcome measures and variable evaluation of findings with dysphagia literature, yet the expansion of P-HRM in the clinical setting has been idling in the face of existing barriers. The novel findings in this thesis are important for the provision of meaningful translation of P-HRM-I technology to the clinical setting. In each of the studies, the application of P-HRM-I to determine the underlying pathophysiology and localise the mechanistic alteration in swallowing demonstrates the utility of P-HRM for clinical dysphagia assessment, with findings that can assist clinicians to provide better tailored and efficacious dysphagia management. The P-HRM-I derived biomechanical patterns identified in these studies have formed the foundation for proposing a P-HRM-I Classification Framework to assist

clinicians in the interpretation of P-HRM-I assessment findings, which aims to address one of the barriers limiting the uptake of P-HRM-I in the clinical setting.

Keywords: manometry, dysphagia, head and neck cancer, obstructive sleep apnea

Subject: Medical Science thesis

Thesis type: Doctor of Philosophy
Completed: 2022
School: College of Medicine and Public Health
Supervisor: Professor Taher Omari