Regulation of Transglottal Airflow in Speakers With Parkinson's Disease.

The purpose of this study was to investigate how speakers with Parkinson's disease (PD) regulate transglottal airflow during phonation within and across breath groups, compared to healthy older adult (HOA) speakers. Aerodynamic recordings from 22 speakers with PD and 22 HOA speakers were compared. Transglottal airflow was measured from vocalic portions of consonant-vowel syllables and an all-voiced sentence using a pneumotachograph. Mean airflow in vowels and sentences in addition to the regularity (standard deviation) of airflow within and across separate productions (different breath groups) was computed. Results indicated that speakers with PD manifested significantly greater mean airflow in vowels and sentences compared to HOA speakers. The regulation of airflow was significantly more variable in vowels both within and across breath groups in speakers with PD. In addition, the regulation of airflow in sentences was significantly more variable across breath groups in speakers with PD. These findings support the theory that speakers with PD exhibit impairments in the ability to control transglottal airflow in phonation. Results indicated that speakers with PD manifested elevated measures of transglottal airflow, which on average fall outside of reported ranges of normal and are different than older adults without PD. Furthermore, this study found that speakers with PD have difficulty regulating the consistency of transglottal airflow during phonation, both within and across breath groups. Whether these impairments result from glottal insufficiency due to peripheral structural changes, central motor dysregulation, or both is in need of further investigation.