# Pharyngeal adaptation to bolus properties in patients with Parkinson’s disease

## TL;DR

This study examines how Parkinson's disease affects swallowing mechanics in response to different food textures and volumes.

## Contribution

It identifies early pharyngeal and esophageal changes in PD patients linked to bolus properties and self-reported swallowing difficulties.

## Key findings

- Abnormal UES relaxation and distension were observed across varied bolus conditions.
- Elevated pharyngeal and UES contractility occurred with thinner liquid trials.
- Bolus volume and viscosity significantly affected swallowing timing metrics.

## Abstract

Dysphagia is common in people with Parkinson’s disease (PD). Yet, literature describing swallow function in PD using high-resolution manometry is limited. This study explored swallowing pressure metrics for varied bolus conditions in people with PD.

A solid-state unidirectional catheter was used to acquire manometric data for triplicate swallows (5 ml, 10 ml, 20 ml; IDDSI 0, 2 & 4). Penetration-aspiration severity was rated during videofluoroscopy. Patient-reported measures included PDQ-8: Parkinson’s Disease Questionnaire-8 and EAT-10: Eating Assessment Tool-10. Quantitative manometric swallow analysis was completed through Swallow Gateway™. Metrics were compared to published normative values and generalized linear model tests explored modulatory effects.

21 participants (76% male; mean age 69.6 years, SD 7.1) with mild-moderate severity PD were studied. Two patients (9%) aspirated for single bolus thin liquid and paste trials and 15 patients (73%) scored > 3 EAT-10. Standardized PDQ-8 scores correlated with EAT-10 (p < 0.05). Abnormality in UES relaxation and distension was demonstrated by high UES integrated relaxation pressure and low UES maximum admittance (UES MaxAdm) values across varied bolus conditions. Participants demonstrated abnormally elevated pharyngeal contractility and increased post-swallow upper-esophageal sphincter (UES) contractility for thinner liquid trials. Alterations in volume and viscosity had significant effects on the bolus timing metric—distention to contraction latency. UES peak pressure measures were altered in relation to bolus viscosity.

This study identifies early pharyngoesophageal contractile changes in relation to bolus volume and viscosity in PD patients, associated with subtle deterioration of self-reported swallow scores. Manometric evaluation may offer insight into PD-related swallowing changes and help optimize diagnostics and treatment planning

The online version contains supplementary material available at 10.1007/s00405-024-08774-y.