Asymmetric vibration in a two-layer vocal fold model with left-right stiffness asymmetry: Experiment and simulation

Zhang, Zhaoyan; Luu, Trung Hieu

doi:10.1121/1.4739437

Cited by 51 publications

(61 citation statements)

References 22 publications

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“…For simplicity, left-right symmetry in vocal fold geometry and vibration about the glottal midline was imposed so that only one vocal fold was considered in this study with the contralateral fold exhibiting mirror-image motion. Extension of the model to left-right asymmetric conditions is straightforward as in Zhang and Luu (2012). For simplicity, the vocal fold model was further assumed to have a uniform cross-sectional geometry along the AP direction, as in many previous studies of phonation (e.g., Scherer et al, 2001;Zheng et al, 2011;Bhattacharya and Siegmund, 2013).…”

Section: Methodsmentioning

confidence: 99%

Regulation of glottal closure and airflow in a three-dimensional phonation model: Implications for vocal intensity control

Zhang¹

2015

The Journal of the Acoustical Society of America

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Maintaining a small glottal opening across a large range of voice conditions is critical to normal voice production. This study investigated the effectiveness of vocal fold approximation and stiffening in regulating glottal opening and airflow during phonation, using a three-dimensional numerical model of phonation. The results showed that with increasing subglottal pressure the vocal folds were gradually pushed open, leading to increased mean glottal opening and flow rate. A small glottal opening and a mean glottal flow rate typical of human phonation can be maintained against increasing subglottal pressure by proportionally increasing the degree of vocal fold approximation for low to medium subglottal pressures and vocal fold stiffening at high subglottal pressures. Although sound intensity was primarily determined by the subglottal pressure, the results suggest that, to maintain small glottal opening as the sound intensity increases, one has to simultaneously tighten vocal fold approximation and/or stiffen the vocal folds, resulting in increased glottal resistance, vocal efficiency, and fundamental frequency.

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Section: Methodsmentioning

confidence: 99%

Regulation of glottal closure and airflow in a three-dimensional phonation model: Implications for vocal intensity control

Zhang¹

2015

The Journal of the Acoustical Society of America

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“…For small values of body stiffness (E b,left < 10 kPa or large left-right stiffness mismatch), only the soft left vocal fold was strongly excited, whereas the stiff fold barely vibrated. Phonation frequency was determined by the stiffness of the soft fold alone and followed close to that of the soft fold in a symmetric condition (see Zhang and Luu, 2012, for more details of the vibration pattern). The left-right amplitude ratio in this regime was thus very large, and there was a phase difference of about 180 between the vibration of the two folds (Fig.…”

Section: A Symmetric Conditions (Series I)mentioning

confidence: 99%

“…Phonation frequency in this regime was determined by stiffness of both folds. More details of the vibratory pattern within these two regimes can be found in Zhang and Luu (2012).…”

Section: A Symmetric Conditions (Series I)mentioning

confidence: 99%

“…The soft fold dominated in the sense that only the soft fold was strongly excited (Fig. 8), and phonation frequency was determined primarily by the properties of the soft fold (Zhang and Luu, 2012). The other fold was entrained to vibrate at the same frequency but with a much smaller amplitude.…”

Section: Asymmetric Conditions With a Soft-body Reference Vocal Fomentioning

confidence: 99%

“…Clinically, this suggests that a vibration pattern with left-right asymmetry may not necessarily cause a salient change in voice quality. However, measures of such asymmetry may provide information regarding the underlying stiffness mismatch and thus may still be important in the diagnosis of a weakened fold in unilateral vocal fold paresis and paralysis (Zhang and Luu, 2012).…”

Section: Asymmetric Conditions With a Soft-body Reference Vocal Fomentioning

confidence: 99%

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Acoustic and perceptual effects of changes in body layer stiffness in symmetric and asymmetric vocal fold models

Zhang¹,

Kreiman²,

Gerratt³

et al. 2013

The Journal of the Acoustical Society of America

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At present, it is not well understood how changes in vocal fold biomechanics correspond to changes in voice quality. Understanding such cross-domain links from physiology to acoustics to perception in the "speech chain" is of both theoretical and clinical importance. This study investigates links between changes in body layer stiffness, which is regulated primarily by the thyroarytenoid muscle, and the consequent changes in acoustics and voice quality under left-right symmetric and asymmetric stiffness conditions. Voice samples were generated using three series of two-layer physical vocal fold models, which differed only in body stiffness. Differences in perceived voice quality in each series were then measured in a "sort and rate" listening experiment. The results showed that increasing body stiffness better maintained vocal fold adductory position, thereby exciting more high-order harmonics, differences that listeners readily perceived. Changes to the degree of left-right stiffness mismatch and the resulting left-right vibratory asymmetry did not produce perceptually significant differences in quality unless the stiffness mismatch was large enough to cause a change in vibratory mode. This suggests that a vibration pattern with left-right asymmetry does not necessarily result in a salient deviation in voice quality, and thus may not always be of clinical significance.

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A numerical strategy for finite element modeling of frictionless asymmetric vocal fold collision

Granados

Misztal

Brunskog

et al. 2016

Numer Methods Biomed Eng

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Document Version Peer reviewed version Link back to DTU Orbit Citation (APA):Granados, A., Misztal, M. K., Brunskog, J., Visseq, V., & Erleben, K. (2016) . SUMMARYAnalysis of voice pathologies may require vocal fold models that include relevant features such as vocal fold asymmetric collision. The present study numerically addresses the problem of frictionless asymmetric collision in a self-sustained three-dimensional continuum model of the vocal folds. Theoretical background and numerical analysis of the finite-element position-based contact model are presented, along with validation. A novel contact detection mechanism capable to detect collision in asymmetric oscillations is developed. The effect of inexact contact constraint enforcement on vocal fold dynamics is examined by different variational methods for inequality constrained minimization problems, namely the Lagrange multiplier method and the penalty method. In contrast to the penalty solution, which is related to classical spring-like contact forces, numerical examples show that the parameter-independent Lagrange multiplier solution is more robust and accurate in the estimation of dynamical and mechanical features at vocal fold contact. Furthermore, special attention is paid to the temporal integration schemes in relation to the contact problem, the results suggesting an advantage of highly diffusive schemes. Finally, vocal fold contact enforcement is shown to affect asymmetric oscillations. The present model may be adapted to existing vocal fold models, which may contribute to a better understanding of the effect of the non-linear contact phenomenon on phonation.

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Asymmetric vibration in a two-layer vocal fold model with left-right stiffness asymmetry: Experiment and simulation

Cited by 51 publications

References 22 publications

Regulation of glottal closure and airflow in a three-dimensional phonation model: Implications for vocal intensity control

Regulation of glottal closure and airflow in a three-dimensional phonation model: Implications for vocal intensity control

Acoustic and perceptual effects of changes in body layer stiffness in symmetric and asymmetric vocal fold models

A numerical strategy for finite element modeling of frictionless asymmetric vocal fold collision

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