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Date Permissions Signed


Date of Award


Document Type

Masters Thesis

Degree Name

Master of Arts (MA)


Communication Sciences and Disorders

First Advisor

Mathers-Schmidt, Barbara A.

Second Advisor

Zeine, Lina

Third Advisor

Fraas, Michael


The purpose of this study was to determine if respiratory muscle strength training (RMST) results in increased measures of respiratory function, improved vocal quality, and improved quality of life as perceived by the participants. Data obtained by this study adds to the body of knowledge regarding clinical use of RMST for SLPs working with patients with Parkinson's disease (PD). The study was comprised of a 13-week ABAB within-subject design with a baseline period, five weeks of respiratory training (Phase 1), three weeks without training (Detraining Phase), and five weeks with training (Phase 2). Three individuals with moderate PD (1M, 2F) participated. They were taught to use the PowerLung® respiratory training device and completed twice daily sessions of expiratory and inspiratory muscle training, five days per week. Outcome measures included maximum inspiratory and expiratory pressures (MIP and MEP, respectively); forced vital capacity (FVC), percent predicted forced vital capacity (FVC%), and forced expiratory volume in 1 second (FEV1); and sustained vowel phonation. Measurements were taken at baseline, before and after detraining (where applicable), and at the end of the study. Results indicated improved maximum respiratory pressures for all participants from baseline to end of study. No participant showed significant changes in FVC, FVC%, and FEV 1, and results of sustained vowel phonation varied. Participants' vocal quality was evaluated by three independent raters as well as the subjects themselves and two conversation partners. Two CSD graduate students and one certified SLP rated subjects' voices at baseline and at the end of treatment using recorded conversation samples and the GRBAS Voice Rating Scale (Hirano, 1981). Improvement in vocal quality was perceived in two participants, and no change was seen in the other. Participants and two conversation partners completed the Perceptual Rating Form to report on vocal quality. Participants noted improvement in vocal quality; conversation partners reported both improvement and decline in various aspects of two participants' vocal quality. Participants completed two surveys regarding the impact of their voice on overall communication and quality of life. These surveys, completed at the start of the study and at completion of each phase, were the Voice Handicap Index (VHI) (Jacobson, et al., 1997) and The Communicative Participation Item Bank General Short Form (Baylor et al. [under review]). Responses from participants revealed inconsistent effects of RMST on quality of life. Results of this study demonstrate that the combination of inspiratory and expiratory muscle strength training in individuals with moderate Parkinson's disease may be a beneficial treatment to improve respiratory function and positively impact vocal quality and overall quality of life as it relates to communicative participation. Results from this study revealed the potential for additional research on the effects of RMST on pulmonary functions such as vital capacity (VC) and total lung capacity (TLC), which are not dependent on maximum speed and effort. Additionally, further investigation of RMST on quality of life is warranted in areas related to voice and communication, as well as overall physical and emotional wellbeing.





Western Washington University

OCLC Number


Subject – LCSH

Respiratory muscles; Muscle strength; Breathing exercises--Therapeutic use; Vocal cords; Parkinson's disease--Treatment--Evaluation; Quality of life




masters theses




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