The study investigated the impact of arytenoid adduction degree (DAA) on acoustic output, aerodynamic behavior, and glottal dynamics using an excised human hemilarynx model. The main objective was to pinpoint perturbation and vibratory parameters sensitive to systematic changes in arytenoid rotation. Nine excised human hemilarynges were utilized to mimic three adduction levels: DAA1, DAA2, and DAA3, achieved by applying 10 g, 20 g, and 50 g weights to threads connected to the arytenoid cartilage. A grid of 35 markers was positioned along the vocal fold's medial surface to facilitate detailed three-dimensional reconstruction of vocal fold movement. Phonation was initiated at five airflow rates, commencing at phonation onset and increasing in four successive 5 L/min steps. Acoustic, aerodynamic, and high-speed video data were simultaneously captured.
The fundamental frequency, glottal resistance, and vocal efficiency, as well as empirical eigenfunction 2 and the lateral maximum displacement, showed systematic sensitivity to increasing DAA. A robust linear correlation revealed a high association between the fundamental frequencies derived from audio and video analyses (R² = .9799). These findings suggest that arytenoid adduction predominantly influences the lateral aspect of vocal fold vibration, significantly increasing the fundamental frequency of phonation.