Subglottic stenosis (SGS) is a narrowing of the airway below the vocal folds and above the trachea. This narrowing may be idiopathic or caused by scarring in the airway due to prolonged endotracheal intubation, radiation therapy, trauma, or gastroesophageal reflux disease. People who present with SGS often experience respiratory difficulty both at rest and during exertion. Breathing difficulty increases with stenosis severity. SGS is also associated with voice problems. Research has identified relationships among stenosis severity, voice function and certain types of surgical management; however, many aspects of these relationships are not fully understood due to the complexities of studying human phonation in this population. The purpose of the present study was to examine the effects of SGS on aerodynamic features of voice function using an excised larynx benchtop mechanical model. Specifically, this research involved the comparison of excised porcine vocal fold vibration at baseline and under experimental conditions of 50% and 75% stenosed. The dependent variable was phonation threshold pressure (PTP), the minimum pressure needed to initiate and maintain vocal fold vibration. PTP was analyzed for nine excised porcine larynges, sampled three times each, at baseline and the two stenosis conditions. The results of this study revealed no differences in PTP based on within-subjects comparisons. Because airflow changes with airway narrowing, this finding might indicate that other factors are responsible for the voice problems associated with SGS that were not accounted for in the current mechanical model. Vocal fold tone is not easily simulated in a benchtop setup and might be an important consideration for future studies. The quantification and manipulation of vocal fold adduction, as well as the study of high-speed imaging, could be useful in future work involving excised larynx mechanical models for the study of SGS. The results from this pilot work represent an important step toward optimizing the experimental setup for studying aerodynamic features of SGS.
College and Department
David O. McKay School of Education; Communication Disorders
BYU ScholarsArchive Citation
Murphey, Jessica Maryn, "Modeling Subglottic Stenosis Effects on Phonation Threshold Pressure in the Porcine Larynx" (2019). Theses and Dissertations. 8273.
subglottic stenosis, larynx, voice disorders, benchtop model, phonation threshold pressure, phonation threshold flow