Spatiotemporal distribution of the intraglottal pressure and vocal fold contact pressure in excised larynges

The contact pressure experienced by the vocal folds during phonation is considered a major factor contributing to vocal fold injuries and lesions. Understanding the spatiotemporal distribution of vocal fold contact pressure across the medial surface and its dependence on laryngeal geometrical and mechanical properties (such as glottal gap, vocal fold vertical thickness, vocal fold length, and vocal fold stiffness) is essential to identifying strategies that minimize contact pressure and reduce the risk of vocal injury. This study aims to characterize the spatiotemporal distribution of intraglottal pressure across the medial surface in excised larynges. The intraglottal pressure was measured using a modified probe microphone at different locations within the vertical plane containing the glottal centerline (mid-sagittal plane), following a grid-like pattern. The resulting pressure distribution maps indicate small variations of intraglottal pressure in the anterior-posterior dimension, but large, complex variations in the vertical dimension. A criterion, derived from applying Bernoulli's equation to vocal fold vibration with prescribed vocal fold contact, was developed to identify the contact pressure peak as a rapid increase in the intraglottal pressure preceded by a negative pressure in the intraglottal pressure waveform. This criterion also allows estimation of the vertical span of vocal fold contact (by extension the vocal fold vertical thickness) and the mucosal wave speed. The preliminary results from this study indicate that the vocal fold vertical thickness has a large impact on the peak contact pressure value, which corroborates findings from previous computational studies.