Assessment of local vocal fold deformation characteristics in an in vitro static tensile test

Abstract

Voice quality is strongly dependent on vocal fold dynamics, which in turn are dependent on lung pressure and vocal fold biomechanics. Numerical and physical models are often used to investigate the interactions of these different subsystems. However, the utility of numerical and physical models is limited unless appropriately validated with data from physiological models. Hence a method that enables analysis of local vocal fold deformations along the entire surface is presented. In static tensile tests, forces are applied to distinctive working points being located in cover and muscle, respectively, so that specific layer properties can be investigated. The forces are directed vertically upward and are applied along or above the vocal fold edge. The resulting deformations are analyzed using multiple perspectives and three-dimensional reconstruction. Deformation characteristics of four human vocal folds were investigated. Preliminary results showed two phases of deformation: a range with a small slope for small deformations fading into a significant nonlinear deformation trend with a high slope. An increase of tissue stiffness from posterior to anterior was detected. This trend is more significant for muscle and in the mid-anterior half of the vocal fold.

Indentation of poroviscoelastic vocal fold tissue using an atomic force microscope

“…2 and Miri et al, 2013), and human NLSM results (Miri et al, 2012c) suggests that porcine VFs are much less differentiated than human VFs. The special homogeneity of VF tissue along anterior–posterior direction was subject of pervious research (Dollinger et al, 2011; Kelleher et al, 2010). Similar to our results, point force excitations (Dollinger et al, 2011) showed that stiffness increases from the central region to the cartilaginous anterior– posterior ends for human tissue, in contrast with those of tensile test (Kelleher et al, 2010).…”

“…The special homogeneity of VF tissue along anterior–posterior direction was subject of pervious research (Dollinger et al, 2011; Kelleher et al, 2010). Similar to our results, point force excitations (Dollinger et al, 2011) showed that stiffness increases from the central region to the cartilaginous anterior– posterior ends for human tissue, in contrast with those of tensile test (Kelleher et al, 2010). Finite element models have shown that anisotropy affects the eigenfrequencies of VF tissue (Kelleher et al, 2010).…”

Mechanical Characterization of Vocal Fold Tissue: A Review Study

“…A hemilarynx setup was used to impose a map of static tensile point forces about 0.1-1 N over the superior surface of the human vocal folds. 55 After reconstruction of the 3D deformation field, the deformation-to-force ratio was determined. This ratio uniformly decreased from the posterior region to the anterior region, in contrast to what was found by the LSR study.…”

Pipette aspiration applied to the characterization of nonhomogeneous, transversely isotropic materials used for vocal fold modeling

“…In addition to studying vocal fold properties and geometry, experiments are often performed to study the mechanics of vocal fold flow-induced vibration (e.g., [9, 10]). With respect to reliable measurement methods to determine these mechanics, reproducible specimens are needed that withstand several investigations without changes in their material properties.…”