Respiratory-swallowing Measures and the Impact of Bolus Hold in Individuals with Parkinson's Disease.

Respiratory and swallowing impairments are common in Parkinson's disease (PD), potentially disrupting respiratory-swallow coordination. This study aimed 1) to examine respiratory-swallowing phase patterns and respiratory cessation duration in individuals with PD across varying bolus consistencies and swallow tasks, and 2) to investigate the influence of the 'bolus hold' verbal cue on these measures. Twenty individuals with PD (mean age = 71.7 years, 6 female) completed 14 swallow trials with varying bolus consistencies (thin, nectar, honey, pudding, solid) and tasks (5mL, 20mL) with each trial presented twice. Respiratory kinematic and airflow measures were recorded using respiratory inductance plethysmography and nasal cannula. Descriptive statistics, estimating equations, and linear models were used to analyze the effects of bolus consistency, swallow task, and bolus hold on phase patterns and cessation duration. Participants exhibited sub-optimal respiratory-swallowing phase patterns but optimal cessation durations, compared to healthy adults. Trends indicated that thicker and smaller boluses were associated with increased EX-EX patterns, and thicker consistencies, nectar (p = 0.049), honey (p = 0.002), pudding (p = 0.002), significantly shortened cessation durations compared to thin liquids. The bolus hold condition trended towards optimal patterns and shorter cessation durations, with significant changes in pattern for thin 5mL (p = 0.035), thin cup sip 20mL (p = 0.020), and pudding (p = 0.025) consistencies, and in cessation duration for thin cup sip 20 mL swallows (p = 0.014). Understanding how these factors contribute to respiratory phase patterns and cessation durations, critical elements for airway protection and bolus clearance, has significant implications for clinical instructions and strategies used with individuals with PD during swallowing rehabilitation.