Modulation of Pharyngeal Swallowing by Bolus Volume and Viscosity.

BACKGROUND Oro-pharyngeal swallowing involves complex neuromodulation to accommodate changing bolus characteristics. The pressure events during deglutitive pharyngeal reconfiguration and bolus flow can be assessed quantitatively using high-resolution pharyngeal manometry (HRPM) with impedance. METHODS An 8 French solid-state unidirectional catheter (32 pressure sensors, 16 impedance segments) was used to acquire triplicate swallows of 3- to 20- mls across 3 viscosity levels using a Standardized Bolus Medium (SBMkit) product (Trisco Pty Ltd, Australia). An online platform www.swallowgateway.com (Flinders University, South Australia) was used to semi -automate swallow analysis. RESULTS 50 healthy adults (29 female, 21 male, mean age 46 years) were studied. Hypopharyngeal intrabolus pressure, upper esophageal sphincter (UES) maximum admittance, UES relaxation pressure and UES relaxation time revealed the most significant modulation effects to bolus volume and viscosity. Pharyngeal contractility and UES post swallow pressures elevated as bolus volumes increased. Bolus viscosity augmented UES preopening pressure only. CONCLUSION Describing swallow modulatory effects with quantitative methods in line with a core outcome set of metrics, and a unified analysis system for broad reference contributes to diagnostic frameworks for oropharyngeal dysphagia.