The impact of Expiratory Muscle Strength Training on Speech Breathing in Individuals With Parkinson's Disease: A Preliminary Study

Purpose: The purpose of this study was to examine the impact of expiratory muscle strength training on speech breathing and functional speech outcomes in individuals with Parkinson's disease (PD). Method: Twelve individuals with PD were seen once a week for 8 weeks: 4 pretraining (baseline) sessions followed by a 4-week training period. Posttraining data were collected at the end of the 4th week of training. Maximum expiratory pressure, an indicator of expiratory muscle strength, and lung volume at speech initiation were the primary outcome measures. Secondary outcomes included lung volume at speech termination, lung volume excursion, utterance length, and vocal intensity. Data were collected during a spontaneous speech sample. Individual effect sizes >1 were considered significant. Results: Maximum expiratory pressure increased in a majority of participants after training. Training resulted in 2 main respiratory patterns: increasing or decreasing lung volume initiation. Lung volume termination and excursion, utterance length, and vocal loudness were not consistently altered by training. Conclusions: Preliminary evidence suggests that the direct physiologic intervention of the respiratory system via expiratory muscle strength training improves speech breathing in individuals with PD, with participants using more typical lung volumes for speech following treatment.