Impact of Expiratory Muscle Strength Training on Voluntary Cough and Swallow Function in Parkinson Disease

Background: Cough provides high expiratory airflows to aerosolize and remove material that cannot be adequately removed by ciliary action. Cough is particularly important for clearing foreign particles from the airway in those with dysphagia who may be at risk for penetration/aspiration (P/A). Expiratory muscle strength training (EMST) was tested to improve cough and swallow function. Methods: Ten male participants, diagnosed with Parkinson disease (PD), with videofluorographic evidence of penetration or with evidence for aspiration of material during swallow of a thin 30-mL bolus, completed 4 weeks of an EMST program to test the hypothesis that EMST would improve cough and/or swallow function. Measured parameters from an airflow waveform produced during voluntary cough, pre-EMST and post-EMST, included inspiration phase duration, compression phase duration (CPD), expiratory phase peak flow (EPPF), expiratory phase rise time (EPRT), and cough volume acceleration (VA) [ie, the EPPF/EPRT ratio]. The swallow outcome measure was the degree of P/A during the swallow task. Results: There was a significant decrease in the duration of the CPD and EPRT; the decrease in EPRT resulted in a significant increase in cough VA. Significant decreases in the P/A scores were found posttraining. Conclusions: The results demonstrate that EMST is a viable treatment modality for a population of participants with PD at risk of aspiration. (CHEST 2009; 135:1301-1308)