Role of gradients in vocal fold elastic modulus on phonation.

New studies show that the elastic properties of the vocal folds (VFs) vary locally. In particular strong gradients exist in the distribution of elastic modulus along the length of the VF ligament, which is an important load-bearing constituent of the VF tissue. There is further evidence that changes in VF health are associated with alterations in modulus gradients.

Collagen microstructure in the vocal ligament: initial results on the potential effects of smoking.

Objectives/hypothesis: This investigation quantitatively characterizes the collagenous microstructure of human vocal ligament specimens excised postmortem from nonsmokers and smokers.

Study Design: Retrospective cohort study.

Methods: Second harmonic generation (SHG) imaging was performed at three anatomical locations of vocal ligament specimens: anterior, mid-membranous, and posterior regions.

The anisotropic hyperelastic biomechanical response of the vocal ligament and implications for frequency regulation: a case study.

One of the primary mechanisms to vary one's vocal frequency is through vocal fold length changes. As stress and deformation are linked to each other, it is hypothesized that the anisotropy in the biomechanical properties of the vocal fold tissue would affect the phonation characteristics. A biomechanical model of vibrational frequency rise during vocal fold elongation is developed which combines an advanced biomechanical characterization protocol of the vocal fold tissue with continuum beam models.

Empirical measurements of biomechanical anisotropy of the human vocal fold lamina propria.

The vocal folds are known to be mechanically anisotropic due to the microstructural arrangement of fibrous proteins such as collagen and elastin in the lamina propria. Even though this has been known for many years, the biomechanical anisotropic properties have rarely been experimentally studied. We propose that an indentation procedure can be used with uniaxial tension in order to obtain an estimate of the biomechanical anisotropy within a single specimen.

Could spatial heterogeneity in human vocal fold elastic properties improve the quality of phonation?

The physical mechanisms leading to the acoustic and perceptual qualities of voice are not well understood. This study examines the spatial distribution of biomechanical properties in human vocal folds and explores the consequences of these properties on phonation. Vocal fold lamina propria specimens isolated from nine excised human male larynges were tested in uniaxial tension (six from non-smokers, three from smokers).

Optical measurements of vocal fold tensile properties: implications for phonatory mechanics.

In voice research, in vitro tensile stretch experiments of vocal fold tissues are commonly employed to determine the tissue biomechanical properties. In the standard stretch-release protocol, tissue deformation is computed from displacements applied to sutures inserted through the thyroid and arytenoid cartilages, with the cartilages assumed to be rigid. Here, a non-contact optical method was employed to determine the actual tissue deformation of vocal fold lamina propria specimens from three excised human larynges in uniaxial tensile tests.