Frequency Response of Synthetic Vocal Fold Models With Linear and Nonlinear Material Properties

Shaw, Stephanie M.; Thomson, Scott L.; Dromey, Christopher; Smith, Simeon L.

doi:10.1044/1092-4388(2012/11-0153)

Cited by 15 publications

(18 citation statements)

References 34 publications

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“…This fiber was intended to approximate the anisotropy of the ligament in a manner such that inferior-superior motion was reduced; this effect is demonstrated and discussed in Murray and Thomson. 22 (The other layers were isotropic, although the use of anisotropic materials such as those recently described elsewhere, 23,24 would be recommended in future studies.) The model geometry was altered to simulate two degrees of bowing (Figure 2).…”

Section: Methodsmentioning

confidence: 99%

A Synthetic, Self-Oscillating Vocal Fold Model Platform for Studying Augmentation Injection

Murray¹,

Thomson²,

Smith³

2014

Journal of Voice

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Objective Design and evaluate a platform for studying the mechanical effects of augmentation injections using synthetic self-oscillating vocal fold models. Study Design Basic science. Methods Life-sized, synthetic, multi-layer, self-oscillating vocal fold models were created that simulated bowing via volumetric reduction of the body layer relative to that of a normal, unbowed model. Material properties of the layers were unchanged. Models with varying degrees of bowing were created and paired with normal models. Following initial acquisition of data (onset pressure, vibration frequency, flow rate, and high-speed image sequences), bowed models were injected with silicone that had material properties similar to those used in augmentation procedures. Three different silicone injection quantities were tested: sufficient to close the glottal gap, insufficient to close the glottal gap, and excess silicone to create convex bowing of the bowed model. The above-mentioned metrics were again taken and compared. Pre- and post-injection high-speed image sequences were acquired using a hemilarynx setup, from which medial surface dynamics were quantified. Results The models vibrated with mucosal wave-like motion and at onset pressures and frequencies typical of human phonation. The models successfully exhibited various degrees of bowing which were then mitigated by injecting filler material. The models showed general pre- to post-injection decreases in onset pressure, flow rate, and open quotient, and a corresponding increase in vibration frequency. Conclusion The model may be useful in further explorations of the mechanical consequences of augmentation injections.

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Section: Methodsmentioning

confidence: 99%

A Synthetic, Self-Oscillating Vocal Fold Model Platform for Studying Augmentation Injection

Murray¹,

Thomson²,

Smith³

2014

Journal of Voice

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“…For example, acrylic and polyester fibers were embedded in the surface layer of an otherwise linear two-layer silicone physical model (Shaw et al, 2012) to achieve vocal fold material nonlinearity. Titze and colleagues (Titze, et al 1995; Chan and Titze, 1997) attached a silicone epithelium membrane onto a stainless steel flat surface and filled the air gap with fluids of varying viscosities to study the dependence of phonation threshold pressure on vocal fold viscosity and geometry.…”

Section: Introductionmentioning

confidence: 99%

Influence of Embedded Fibers and an Epithelium Layer on the Glottal Closure Pattern in a Physical Vocal Fold Model

Xuan

Zhang

2014

J Speech Lang Hear Res

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Purpose To explore the possible structural and material property features that may facilitate complete glottal closure in an otherwise isotropic physical vocal fold model. Method Seven vocal fold models with different structural features were used in this study. An isotropic model was used as the baseline model, and other models were modified from the baseline model by either embedding fibers aligned along the anterior-posterior direction in the body or cover layer, adding a stiffer outer layer simulating the epithelium layer, or a combination of the two features. Phonation tests were performed with both aerodynamic and acoustic measurements and high-speed imaging of vocal fold vibration. Results Compared to the isotropic one-layer model, the presence of a stiffer epithelium layer led to complete glottal closure along the anterior-posterior direction and strong excitation of high-order harmonics in the resulting acoustic spectra. Similar improvements were observed with fibers embedded in the cover layer, but to a lesser degree. Presence of fibers in the body layer did not yield noticeable improvements in glottal closure or harmonic excitation. Conclusions This study shows that the presence of collagen and elastin fibers and the epithelium layer may play a critical role in achieving complete glottal closure.

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“…For this reason, a first approach to mimicking the transversely isotropic behavior of the vocal ligament in a vocal fold model was demonstrated in [22]. In that study a two-layer body-cover model was fabricated and tested.…”

Section: Introductionmentioning

confidence: 99%

“…The fabrication of several inhomogeneous, transversely isotropic silicone specimens with different amounts of anisotropy is described. Similar to the work of [22], elastic fibers were embedded in the silicone rubber to produce specimens that exhibit a transversely isotropic material behavior. Because the human vocal fold ligament is transversely isotropic and the vocal fold replicas investigated in [22] showed similarities with real vocal folds, the present investigation serves as a basis for further studies towards a more realistic vocal fold model.…”

Section: Introductionmentioning

confidence: 99%

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

Weiß

Thomson

Lerch

et al. 2013

Journal of the Mechanical Behavior of Biomedical Materials

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The etiology and treatment of voice disorders are still not completely understood. Since the vibratory characteristics of vocal folds are strongly influenced by both anatomy and mechanical material properties, measurement methods to analyze the material behavior of vocal fold tissue are required. Due to the limited life time of real tissue in the laboratory, synthetic models are often used to study vocal fold vibrations. In this paper we focus on two topics related to synthetic and real vocal fold materials. First, because certain tissues within the human vocal folds are transversely isotropic, a fabrication process for introducing this characteristic in commonly-used vocal fold modeling materials is presented. Second, the pipette aspiration technique is applied to the characterization of these materials. By measuring the displacement profiles of stretched specimens that exhibit varying degrees of transverse isotropy, it is shown that local anisotropy can be quantified using a parameter describing the deviation from an axisymmetric profile. The potential for this technique to characterize homogeneous, anisotropic materials, including soft biological tissues such as those found in the human vocal folds, is supplemented by a computational study.

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Frequency Response of Synthetic Vocal Fold Models With Linear and Nonlinear Material Properties

Cited by 15 publications

References 34 publications

A Synthetic, Self-Oscillating Vocal Fold Model Platform for Studying Augmentation Injection

A Synthetic, Self-Oscillating Vocal Fold Model Platform for Studying Augmentation Injection

Influence of Embedded Fibers and an Epithelium Layer on the Glottal Closure Pattern in a Physical Vocal Fold Model

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

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