Rehabilitating Cough Dysfunction in Parkinson's Disease: A Randomized Controlled Trial

Abstract

A BS TRACT: Background: Disorders of airway protection (cough and swallowing) are pervasive in Parkinson's disease (PD) resulting in a high incidence of aspiration pneumonia and death. However, there are no randomized controlled trials comparing strength and skill-based approaches to improve airway protection in PD. Objectives: The aim of this study was to compare expiratory muscle strength training (EMST) and sensorimotor training for airway protection (smTAP) to improve coughrelated outcomes in people with PD. Methods: Participants with PD and dysphagia were recruited for this prospective phase II randomizedblinded controlled clinical trial. Participants completed baseline assessment, 5 weeks of EMST or smTAP, and a post-training assessment. Primary outcome measures included maximum expiratory pressure (MEP) and voluntary cough peak expiratory flow rate (PEFR). Mixed effects models were used to assess the effects of EMST and smTAP on outcomes.Results: A total of 65 participants received either EMST (n = 34) or smTAP (n = 31). MEP improved from pre-to post-treatment for smTAP (P < 0.001, d = 0.19) and EMST (P < 0.001, d = 0.53). Voluntary PEFR increased from pre-to post-treatment for smTAP (P < 0.001, d = 0.19) and EMST (P < 0.001, d = 0.06). Moreover, reflex cough PEFR (P < 0.001, d = 0.64), reflex cough expired volume (P < 0.001, d = 0.74), and urge to cough (P = 0.018, OR = 2.70) improved for the smTAP group but not for the EMST group. Conclusions: This clinical trial confirmed the efficacy of smTAP to improve reflex and voluntary cough function, above and beyond EMST, the current gold standard.

Cough and Swallowing Therapy and Their Effects on Vocal Fold Bowing and Laryngeal Lesions

“…A preliminary study investigating the feasibility of smTAP in patients with progressive supranuclear palsy (PSP) showed a significant increase in peak expiratory flow rate (PEFR) after one session of smTAP which supports the feasibility and highlights the potential for further use in the future 10 . Furthermore, a recently published randomized controlled trial showed the superior efficacy of smTAP over EMST on improving reflex and voluntary cough 20 …”

“…The beneficial effects of EMST and smTAP on cough effectiveness has been shown in the literature. 8,10,20 These training modalities require repetitive and forceful exhaling (EMST) and coughing (smTAP) that increases the force applied to the vocal folds. The present study is the first to investigate the bulking and traumatic effects of these training modalities.…”

“…It is known that smTAP and EMST increases cough strength. 20 Additionally, it is reported that BI might be correlated with cough effectiveness. 21,22 However, studies investigating the effects of respiratory training techniques on BI, including this one, have not shown significant changes to BI.…”

“…This was a secondary analysis of data collected as part of a prospective, double blinded, randomized controlled trial (RCT). 20 All procedures performed were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Approval was obtained from the Institutional Review Board of the two study sites Teachers College, Columbia University (no: 16-098) and University of Florida (IRB201601082).…”

“…10 Furthermore, a recently published randomized controlled trial showed the superior efficacy of smTAP over EMST on improving reflex and voluntary cough. 20 Vocal fold bowing Index (BI) is a pixel-based measurement used to quantify vocal fold bowing. BI has recently been used to delineate the near-normal and impaired swallowing function in PwPD and has been correlated to decreased peak expiratory flow rates during voluntary and reflex cough effectiveness in patients with PSP.…”