A three-dimensional model of vocal fold abduction/adduction

Hunter, Eric J.; Titze, Ingo R.; Alipour, Fariborz

doi:10.1121/1.1652033

Cited by 116 publications

(105 citation statements)

References 40 publications

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“…In particular, in contrast to human or canine phonation (Zemlin, 1988;Hunter et al, 2004;Herbst et al, 2011;Chhetri et al, 2012), the subglottal air pressure ranges and the exact laryngeal configuration for vocal fold adduction in elephants are not known. The position of the arytenoid cartilages in the excised larynx experiment had to be inferred from careful examination of the available CT data and the functional and mechanical possibilities offered by the excised elephant larynx.…”

Section: Physiological Relevancementioning

confidence: 99%

Complex vibratory patterns in an elephant larynx

Švec

Lohscheller

et al. 2013

Journal of Experimental Biology

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SUMMARYElephants' low-frequency vocalizations are produced by flow-induced self-sustaining oscillations of laryngeal tissue. To date, little is known in detail about the vibratory phenomena in the elephant larynx. Here, we provide a first descriptive report of the complex oscillatory features found in the excised larynx of a 25year old female African elephant (Loxodonta africana), the largest animal sound generator ever studied experimentally. Sound production was documented with high-speed video, acoustic measurements, air flow and sound pressure level recordings. The anatomy of the larynx was studied with computed tomography (CT) and dissections. Elephant CT vocal anatomy data were further compared with the anatomy of an adult human male. We observed numerous unusual phenomena, not typically reported in human vocal fold vibrations. Phase delays along both the inferior-superior and anterior-posterior (A-P) dimension were commonly observed, as well as transverse travelling wave patterns along the A-P dimension, previously not documented in the literature. Acoustic energy was mainly created during the instant of glottal opening. The vestibular folds, when adducted, participated in tissue vibration, effectively increasing the generated sound pressure level by 12dB. The complexity of the observed phenomena is partly attributed to the distinct laryngeal anatomy of the elephant larynx, which is not simply a large-scale version of its human counterpart. Travelling waves may be facilitated by low fundamental frequencies and increased vocal fold tension. A travelling wave model is proposed, to account for three types of phenomena: A-P travelling waves, 'conventional' standing wave patterns, and irregular vocal fold vibration. Supplementary material available online at

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Section: Physiological Relevancementioning

confidence: 99%

Complex vibratory patterns in an elephant larynx

Švec

Lohscheller

et al. 2013

Journal of Experimental Biology

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“…Models of abduction and adduction ͑vocal fold posturing͒ have been created by several investigators ͑Farley, 1996; Hunter et al, 2004;Titze and Hunter, 2007͒. These rigorous models of the larynx explore the role of various muscle activations on the control of abduction and adduction, but their simulations require the estimation of complex muscle activation functions, adding complexity and uncertainty.…”

Section: A Model Formulationmentioning

confidence: 99%

A virtual trajectory model predicts differences in vocal fold kinematics in individuals with vocal hyperfunction

Stepp

Hillman

Heaton

2010

The Journal of the Acoustical Society of America

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A simple, one degree of freedom virtual trajectory model of vocal fold kinematics was developed to investigate whether kinematic features of vocal fold movement confirm increased muscle stiffness. Model simulations verified that increases in stiffness were associated with changes in kinematic parameters, suggesting that increases in gesture rate would affect kinematic features to a lesser degree in vocal hyperfunction patients given the increased levels of muscle tension they typically employ to phonate. This hypothesis was tested experimentally in individuals with muscle tension dysphonia ͑MTD; N =10͒ and vocal nodules ͑N =10͒ relative to controls with healthy normal voice ͑N =10͒ who were examined with trans-nasal endoscopy during a simple vocal fold abductory-adductory task. Kinematic measures in MTD patients were less affected by increased gesture rate, consistent with the hypothesis that these individuals have elevated typical laryngeal muscle tension. Group comparisons of the difference between medium and fast gesture rates ͑Mann-Whitney, one-tailed͒ showed statistically significant differences between the control and MTD individuals on the two kinematic features examined ͑p Ͻ 0.05͒. Results in nodules participants were mixed and are discussed independently. The findings support the potential use of vocal fold kinematics as an objective clinical assay of vocal hyperfunction.

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“…Min et al [12] proposed a nonlinear elastic model which captured the equilibrium stress-stretch response but failed to describe the hysteresis of the tissue. Viscoelastic models were employed by Hunter et al [13] and Chan et al [14,15] to simulate the response of the vocal fold lamina propria under cyclic tensile or shear deformation. Our previous work [6] documents a two-network constitutive model to describe the stress-stretch response of the vocal fold lamina propria.…”

Section: Introductionmentioning

confidence: 99%

Predictions of Fundamental Frequency Changes During Phonation Based on a Biomechanical Model of the Vocal Fold Lamina Propria

et al. 2009

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This study examines the local and global changes of fundamental frequency (F 0 ) during phonation and proposes a biomechanical model of predictions of F 0 contours based on the mechanics of vibration of vocal fold lamina propria. The biomechanical model integrates the constitutive description of the tissue mechanical response with a structural model of beam vibration. The constitutive model accounts for the nonlinear and time dependent response of the vocal fold cover and the vocal ligament. The structural model of the vocal fold lamina propria is based on a composite beam model with axial stress. Results show that local fluctuations such as F 0 overshoots and undershoots can be characterized by the biomechanical model and might be related to the processes of stress relaxation of vocal fold tissues during length changes. The global changes of F 0 declination in declarative sentence production can also be characterized by the model. Such F 0 declination is partially attributed to the peak stress decay associated with stress relaxation of the vocal fold lamina propria and partially to neuromuscular control of the vocal fold length.

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A three-dimensional model of vocal fold abduction/adduction

Cited by 116 publications

References 40 publications

Complex vibratory patterns in an elephant larynx

Complex vibratory patterns in an elephant larynx

A virtual trajectory model predicts differences in vocal fold kinematics in individuals with vocal hyperfunction

Predictions of Fundamental Frequency Changes During Phonation Based on a Biomechanical Model of the Vocal Fold Lamina Propria

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