Sequential voluntary cough and aspiration or aspiration risk in Parkinson's disease

Abstract

Background: Disordered swallowing, or dysphagia, is almost always present to some degree in people with Parkinson's disease (PD), either causing aspiration or greatly increasing the risk for aspiration during swallowing. This likely contributes to aspiration pneumonia, a leading cause of death in this patient population. Effective airway protection is dependent upon multiple behaviors, including cough and swallowing. Single voluntary cough function is disordered in people with PD and dysphagia. However, the appropriate response to aspirate material is more than one cough, or sequential cough. The goal of this study was to examine voluntary sequential coughing in people with PD, with and without dysphagia.

Methods: Forty adults diagnosed with idiopathic PD produced two trials of sequential voluntary cough. The cough airflows were obtained using pneumotachograph and facemask and subsequently digitized and recorded. All participants received a modified barium swallow study as part of their clinical care, and the worst penetration-aspiration score observed was used to determine whether the patient had dysphagia.

Results: There were significant differences in the compression phase duration, peak expiratory flow rates, and amount of air expired of the sequential cough produced by participants with and without dysphagia.

Conclusions: The presence of dysphagia in people with PD is associated with disordered cough function. Sequential cough, which is important in removing aspirate material from large- and smaller-diameter airways, is also impaired in people with PD and dysphagia compared with those without dysphagia. There may be common neuroanatomical substrates for cough and swallowing impairment in PD leading to the co-occurrence of these dysfunctions.

Fig. 1

Sequential cough airflow waveform and the cough epoch. Cr cough reacceleration

Fig. 2

Variables measured from the sequential cough airflow wave-form. A–B, compression phase duration (CPD; seconds); C, peak expiratory flow rate (PEFR; L/s); C/(B–C duration; seconds), cough volume acceleration (CVA; L/s/s); B–E, cough-expired air for that cough reacceleration (liters of air, expressed as a percent of total air expired for all reaccelerations in the epoch); D–E, subsequent CPD. Each variable then repeats for the subsequent cough reaccelerations in the epoch

Fig. 3

Illustration of sequential cough epoch organization between the PD-noPA (a) group and PD-PA (b) groups. a Dotted lines represent the compression phase duration (vertical) and peak expiratory flow rate (horizontal) of the first cough in the epoch (horizontal). Shaded areas represent cough-expired volume for each cough reacceleration. b The compression phase duration, peak expiratory flow rate, and cough-expired volume for PD-noPA group superimposed on PD-PA group