Stress relaxation in human true and false vocal folds.

Abstract

Stress relaxation behavior of the human true and false vocal folds were measured in vitro and modeled for viscoelastic parameter determination. Vibrations of the vocal folds are greatly influenced by the elasticity and viscosity of its mucosal layer. When there is a change in the viscoelastic properties of vocal fold tissue due to disease or trauma such as scarring, voice change may occur. Voice simulation models are in need of viscoelastic properties of human vocal folds for more reliable results. Due to the shortage of human data, these properties have been extrapolated from animal data such as canine vocal fold tissues. In this study, samples are made from human larynges acquired from NDRI, which were snap frozen 24–48 h post mortem and stored in −82 °F. Samples were made from medial portion of true and false vocal folds without any muscle, with a piece cartilage at each end for mounting. Stepwise elongation of 20 and 30% stretch was applied the force response was measured with an ergometer and modeled with a quasi‐linear viscoelastic model. The preliminary results suggest the strong relaxation behavior in both true and false vocal folds are indicative of abundant collagen material. [Work supported by NIDCD Grant # DC00956.]