Speaker
Description
Vocal fold (VF) posturing influences the fluid-structure–acoustic interactions that govern human phonation. However, the influence of VF posturing on phonotraumatic vocal hyperfunction is still unclear. This deficiency arises, in part, because current experimental modeling approaches rely on simplified VF and laryngeal geometries with limited degrees of freedom. Consequently, current approaches are unable to replicate different glottal orientations (pressed, breathy, etc.) that can arise due to abnormal VF posturing. In response, this work proposes a physiologically inspired, cyber-physical laryngeal model with three degrees-of-freedom that mimics VF posturing in the transverse glottal plane. Multi-layered synthetic VFs are cast inside a laryngeal structure and attached anteriorly and medially to a representative thyroid cartilage, and posteriorly to moveable arytenoid structures. The silicone VFs include a hollow cylindrical channel along the anterior-posterior direction that can be inflated to mimic VF thickening due to the thyroarytenoid muscle. The positioning and orientation of the arytenoid structure is physically activated with a three degree-of-freedom positioning system that controls medial-lateral and anterior-posterior displacement, and rotation about the cricoarytenoid joint. Kinematics are derived from a numerical model of laryngeal muscle activation. Validation is performed by comparing the model speech parameters (e.g., phonation threshold pressure, flowrate, fundamental frequency, and sound pressure level) with relevant clinical and computational studies, as a function of VF posturing. Good agreement in the dependency of aerodynamic, kinematic, and acoustic parameters on VF posturing is found. This novel approach provides the ability to systematically link VF posturing to phonatory outcomes via experiment, opening a new avenue for exploring the mechanics of phonation in a benchtop facility.