Background

Pneumonia, a leading cause of death in progressive supranuclear palsy (PSP), results from progressive and pervasive deficits of airway protection, including both cough and swallowing dysfunction. Cough protects the airway by expelling aspirate and may be an important therapeutic target to protect against pneumonia in the presence of dysphagia. However, cough has not been objectively characterized in PSP or compared to other common forms of parkinsonism, such as Parkinson's disease (PD).

Objective

The purpose of this study was to examine voluntary and reflex cough function in PSP, as compared to patients with PD matched for disease duration.

Methods

Twenty-six patients with PSP and 26 with PD completed voluntary and reflex cough testing via spirometry. Linear mixed effects models examined comparisons between groups and within cough types across cough sensory and motor outcomes.

Results

Patients with PSP demonstrated significantly reduced cough motor function compared to PD, specifically reduced peak expiratory flow rate (P < 0.001), cough expiratory volume (P < 0.001), and cough inspiratory volume (P = 0.008). Both groups showed similar reflex cough thresholds (P = 0.694), but PSP demonstrated an increased perception of cough stimuli (P = 0.041).

Conclusions

These findings suggest that sensorimotor cough dysfunction is prevalent in PSP, and cough motor deficits, in particular, are worse in PSP than in PD. These deficits likely contribute to the pathogenesis of pneumonia in PSP. Therefore, cough should be integrated into assessments of airway protection and considered as a therapeutic target to potentially reduce adverse health events and improve quality of life in this population. © 2021 International Parkinson and Movement Disorder Society