The Experts below are selected from a list of 5235 Experts worldwide ranked by ideXlab platform
David A Berry - One of the best experts on this subject based on the ideXlab platform.
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visualization and quantification of the Medial Surface dynamics of an excised human vocal fold during phonation
Journal of Voice, 2006Co-Authors: Michael Doellinger, David A BerryAbstract:Summary The purpose of this investigation was to investigate physical mechanisms of vocal fold vibration during normal phonation through quantification of the Medial Surface dynamics of the fold. An excised hemilarynx setup was used. The dynamics of 30 microsutures mounted on the Medial Surface of a human vocal fold were analyzed across 18 phonatory conditions. The vibrations were recorded with a digital high-speed camera at a frequency of 4000 Hz. The positions of the sutures were extracted and converted to three-dimensional coordinates using a linear approximation technique. The data were reduced to principal eigenfuctions, which captured over 90% of the variance of the data, and suggested mechanisms of sustained vocal fold oscillation. The vibrations were imaged as the following phonatory conditions were manipulated: glottal airflow, an adductory force applied to the muscular process, and an elongation force applied to the thyroid cartilage. Over the range of variables studied, only the variation in glottal airflow yielded significant changes in subglottal pressure and fundamental frequency. All recordings showed high correlation for the distribution of the dynamics across the Medial Surface of the vocal fold. The distribution of the different displacement directions and velocities showed the highest variations around the superior region of the Medial Surface. Although the computed vibration patterns of the two largest empirical eigenfunctions were consistent with previous experimental observations, the relative prominence of the two eigenfunctions changed as a function of glottal airflow, impacting theories of vocal efficiency and vocal economy.
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computation of the three dimensional Medial Surface dynamics of the vocal folds
Journal of Biomechanics, 2006Co-Authors: Michael Dollinger, David A BerryAbstract:Abstract To increase our understanding of pathological and healthy voice production, quantitative measurement of the Medial Surface dynamics of the vocal folds is significant, albeit rarely performed because of the inaccessibility of the vocal folds. Using an excised hemilarynx methodology, a new calibration technique, herein referred to as the linear approximate (LA) method, was introduced to compute the three-dimensional coordinates of fleshpoints along the entire Medial Surface of the vocal fold. The results were compared with results from the direct linear transform. An associated error estimation was presented, demonstrating the improved accuracy of the new method. A test on real data was reported including computation of quantitative measurements of vocal fold dynamics.
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a quantitative study of the Medial Surface dynamics of an in vivo canine vocal fold during phonation
Laryngoscope, 2005Co-Authors: Michael Doellinger, David A Berry, Gerald S BerkeAbstract:Objectives/Hypothesis: The purpose of this study was to measure the Medial Surface dynamics of a canine vocal fold during phonation. In particular, displacements, velocities, accelerations, and relative phase velocities of vocal fold fleshpoints were reported across the entire Medial Surface. Although the Medial Surface dynamics have a profound influence on voice production, such data are rare because of the inaccessibility of the vocal folds. Study Design: Medial Surface dynamics were investigated during both normal and fry-like phonation as a function of innervation to the recurrent laryngeal nerve for conditions of constant glottal airflow. Methods: An in vivo canine model was used. The larynx was dissected similar to methods described in previous excised hemilarynx experiments. Phonation was induced with artificial airflow and innervation to the recurrent laryngeal nerve. The recordings were obtained using a high-speed digital imaging system. Three dimensional coordinates were computed for fleshpoints along the entire Medial Surface. The trajectories of the fleshpoints were preprocessed using the method of Empirical Eigenfunctions. Results: Although considerable variability existed within the data, in general, the Medial-lateral displacements and vertical displacements of the vocal fold fleshpoints were large compared with anterior-posterior displacements. For both normal and fry-like phonation, the largest displacements and velocities were concentrated in the upper Medial portion. During normal phonation, the mucosal wave propagated primarily in a vertical direction. Above a certain threshold of subglottal pressure (or stimulation to the recurrent laryngeal nerve), an abrupt transition from chest-like to fry-like phonation was observed. Conclusions: The study reports unique, quantitative data regarding the Medial Surface dynamics of an in vivo canine vocal fold during phonation, capturing both chest-like and fry-like vibration patterns. These data quantify a complex set of dynamics. The mathematical modeling of such complexity is still in its infancy and requires quantitative data of this nature for development, validation, and testing.
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Medial Surface dynamics of an in vivo canine vocal fold during phonation
Journal of the Acoustical Society of America, 2005Co-Authors: Michael Dollinger, David A Berry, Gerald S BerkeAbstract:Quantitative measurement of the Medial Surface dynamics of the vocal folds is important for understanding how sound is generated within the larynx. Building upon previous excised hemilarynx studies, the present study extended the hemilarynx methodology to the in vivo canine larynx. Through use of an in vivo model, the Medial Surface dynamics of the vocal fold were examined as a function of active thyroarytenoid muscle contraction. Data were collected using high-speed digital imaging at a sampling frequency of 2000 Hz, and a spatial resolution of 1024×1024 pixels. Chest-like and fry-like vibrations were observed, but could not be distinguished based on the input stimulation current to the recurrent laryngeal nerve. The subglottal pressure did distinguish the registers, as did an estimate of the thyroarytenoid muscle activity. Upon quantification of the three-dimensional motion, the method of Empirical Eigenfunctions was used to extract the underlying modes of vibration, and to investigate mechanisms of sus...
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empirical eigenfunctions and Medial Surface dynamics of a human vocal fold
Methods of Information in Medicine, 2005Co-Authors: Michael Dollinger, Niro Tayama, David A BerryAbstract:Objectives: The purpose of this investigation was to use an excised human larynx to substantiate physical mechanisms of sustained vocal fold oscillation over a variety of phonatory conditions. During sustained, flowinduced oscillation, dynamical data was collected from the Medial Surface of the vocal fold. The method of Empirical Eigenfunctions was used to analyze the data and to probe physical mechanisms of sustained oscillation. Methods: Thirty microsutures were mounted on the Medial margin of a human vocal fold. Across five distinct phonatory conditions, the vocal fold was set into oscillation and imaged with a high-speed digital imaging system. The position coordinates of the sutures were extracted from the images and converted into physical coordinates. Empirical Eigenfunctions were computed from the time-varying physical coordinates, and mechanisms of sustained oscillation were explored. Results: Using the method of Empirical Eigenfunctions, physical mechanisms of sustained vocal fold oscillation were substantiated. In particular, the essential dynamics of vocal fold vibration were captured by two dominant Empirical Eigenfunctions. The largest Eigenfunction primarily captured the alternating convergent/ divergent shape of the Medial Surface of the vocal fold, while the second largest Eigenfunction primarily captured the lateral vibrations of the vocal fold. Conclusions: The hemi-larynx setup yielded a view of the Medial Surface of the vocal folds, revealing the tissue vibrations which produced sound. Through the use of Empirical Eigenfunctions, the underlying modes of vibration were computed, disclosing physical mechanisms of sustained vocal fold oscillation. The investigation substantiated previous theoretical analyses and yielded significant data to help evaluate and refine computational models of vocal fold vibration.
Gerald S Berke - One of the best experts on this subject based on the ideXlab platform.
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a quantitative study of the Medial Surface dynamics of an in vivo canine vocal fold during phonation
Laryngoscope, 2005Co-Authors: Michael Doellinger, David A Berry, Gerald S BerkeAbstract:Objectives/Hypothesis: The purpose of this study was to measure the Medial Surface dynamics of a canine vocal fold during phonation. In particular, displacements, velocities, accelerations, and relative phase velocities of vocal fold fleshpoints were reported across the entire Medial Surface. Although the Medial Surface dynamics have a profound influence on voice production, such data are rare because of the inaccessibility of the vocal folds. Study Design: Medial Surface dynamics were investigated during both normal and fry-like phonation as a function of innervation to the recurrent laryngeal nerve for conditions of constant glottal airflow. Methods: An in vivo canine model was used. The larynx was dissected similar to methods described in previous excised hemilarynx experiments. Phonation was induced with artificial airflow and innervation to the recurrent laryngeal nerve. The recordings were obtained using a high-speed digital imaging system. Three dimensional coordinates were computed for fleshpoints along the entire Medial Surface. The trajectories of the fleshpoints were preprocessed using the method of Empirical Eigenfunctions. Results: Although considerable variability existed within the data, in general, the Medial-lateral displacements and vertical displacements of the vocal fold fleshpoints were large compared with anterior-posterior displacements. For both normal and fry-like phonation, the largest displacements and velocities were concentrated in the upper Medial portion. During normal phonation, the mucosal wave propagated primarily in a vertical direction. Above a certain threshold of subglottal pressure (or stimulation to the recurrent laryngeal nerve), an abrupt transition from chest-like to fry-like phonation was observed. Conclusions: The study reports unique, quantitative data regarding the Medial Surface dynamics of an in vivo canine vocal fold during phonation, capturing both chest-like and fry-like vibration patterns. These data quantify a complex set of dynamics. The mathematical modeling of such complexity is still in its infancy and requires quantitative data of this nature for development, validation, and testing.
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Medial Surface dynamics of an in vivo canine vocal fold during phonation
Journal of the Acoustical Society of America, 2005Co-Authors: Michael Dollinger, David A Berry, Gerald S BerkeAbstract:Quantitative measurement of the Medial Surface dynamics of the vocal folds is important for understanding how sound is generated within the larynx. Building upon previous excised hemilarynx studies, the present study extended the hemilarynx methodology to the in vivo canine larynx. Through use of an in vivo model, the Medial Surface dynamics of the vocal fold were examined as a function of active thyroarytenoid muscle contraction. Data were collected using high-speed digital imaging at a sampling frequency of 2000 Hz, and a spatial resolution of 1024×1024 pixels. Chest-like and fry-like vibrations were observed, but could not be distinguished based on the input stimulation current to the recurrent laryngeal nerve. The subglottal pressure did distinguish the registers, as did an estimate of the thyroarytenoid muscle activity. Upon quantification of the three-dimensional motion, the method of Empirical Eigenfunctions was used to extract the underlying modes of vibration, and to investigate mechanisms of sus...
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Medial Surface dynamics of the vocal folds in an in vivo canine model
Journal of the Acoustical Society of America, 2004Co-Authors: Michael Doellinger, Dinesh K Chhetri, Gerald S Berke, David A BerryAbstract:Quantitative measurement of the Medial Surface dynamics of the vocal folds is important for understanding how sound is generated in the larynx. However, such data are hard to gather because of the inaccessibility of the vocal folds. Recent studies have applied hemi‐larynx methodology to excised human larynges, to visualize these dynamics. The present study extends this methodology to obtain similar quantitative measurements using an in vivo canine hemi‐larynx setup, with varying levels of stimulation to the recurrent laryngeal nerve. Use of an in vivo model allows us to examine effects of intrinsic muscle contraction on the Medial Surface of the vocal folds, to provide greater insight into mechanisms of vocal control. Data were collected using digital high‐speed imaging with a sampling frequency of up to 4000 Hz, and a spatial resolution of up to 1024×1024 pixels. Three‐dimensional motion will be extracted, computed, visualized, and contrasted as a function of the level of stimulation to the recurrent lar...
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quantitative measurements of the Medial Surface of the vocal folds in an in vivo canine model
2004Co-Authors: Michael Doellinger, Gerald S Berke, David A BerryAbstract:Medial Surface dynamics of the vocal folds are important for an understanding of sound generation within the larynx. Such dynamics illustrate the propagation of the mucosal wave which makes voice production possible. Almost universally, in vivo investigations of vocal fold dynamics are performed using endoscopic techniques which allow only a superior view of vocal fold vibration. Hence, the view onto the Medial margin is blocked which leads to an observation leak within the vocal fold cycle. In this study, an excised hemi-larynx set-up, is adapted for use with an in vivo canine model. In vivo models allow us to examine effects of intrinsic muscle contraction on the Medial Surface dynamics of the vocal folds, and provide greater insight into mechanisms of vocal control. Dynamics, of the vocal folds with varying levels of stimulation to the recurrent laryngeal nerve (RLN) will be shown. In particular, quantitative measurements such as fundamental frequency, vocal intensity, and the dynamics of up to 15 different positions along the Medial Surface of the vocal folds will be presented as a function of RLN innervation. To capture the vibrations, the vocal folds were imaged with a sampling frequency of 2000 Hz, and a spatial resolution of 1024 x 1024 pixels
Michael Doellinger - One of the best experts on this subject based on the ideXlab platform.
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visualization and quantification of the Medial Surface dynamics of an excised human vocal fold during phonation
Journal of Voice, 2006Co-Authors: Michael Doellinger, David A BerryAbstract:Summary The purpose of this investigation was to investigate physical mechanisms of vocal fold vibration during normal phonation through quantification of the Medial Surface dynamics of the fold. An excised hemilarynx setup was used. The dynamics of 30 microsutures mounted on the Medial Surface of a human vocal fold were analyzed across 18 phonatory conditions. The vibrations were recorded with a digital high-speed camera at a frequency of 4000 Hz. The positions of the sutures were extracted and converted to three-dimensional coordinates using a linear approximation technique. The data were reduced to principal eigenfuctions, which captured over 90% of the variance of the data, and suggested mechanisms of sustained vocal fold oscillation. The vibrations were imaged as the following phonatory conditions were manipulated: glottal airflow, an adductory force applied to the muscular process, and an elongation force applied to the thyroid cartilage. Over the range of variables studied, only the variation in glottal airflow yielded significant changes in subglottal pressure and fundamental frequency. All recordings showed high correlation for the distribution of the dynamics across the Medial Surface of the vocal fold. The distribution of the different displacement directions and velocities showed the highest variations around the superior region of the Medial Surface. Although the computed vibration patterns of the two largest empirical eigenfunctions were consistent with previous experimental observations, the relative prominence of the two eigenfunctions changed as a function of glottal airflow, impacting theories of vocal efficiency and vocal economy.
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a quantitative study of the Medial Surface dynamics of an in vivo canine vocal fold during phonation
Laryngoscope, 2005Co-Authors: Michael Doellinger, David A Berry, Gerald S BerkeAbstract:Objectives/Hypothesis: The purpose of this study was to measure the Medial Surface dynamics of a canine vocal fold during phonation. In particular, displacements, velocities, accelerations, and relative phase velocities of vocal fold fleshpoints were reported across the entire Medial Surface. Although the Medial Surface dynamics have a profound influence on voice production, such data are rare because of the inaccessibility of the vocal folds. Study Design: Medial Surface dynamics were investigated during both normal and fry-like phonation as a function of innervation to the recurrent laryngeal nerve for conditions of constant glottal airflow. Methods: An in vivo canine model was used. The larynx was dissected similar to methods described in previous excised hemilarynx experiments. Phonation was induced with artificial airflow and innervation to the recurrent laryngeal nerve. The recordings were obtained using a high-speed digital imaging system. Three dimensional coordinates were computed for fleshpoints along the entire Medial Surface. The trajectories of the fleshpoints were preprocessed using the method of Empirical Eigenfunctions. Results: Although considerable variability existed within the data, in general, the Medial-lateral displacements and vertical displacements of the vocal fold fleshpoints were large compared with anterior-posterior displacements. For both normal and fry-like phonation, the largest displacements and velocities were concentrated in the upper Medial portion. During normal phonation, the mucosal wave propagated primarily in a vertical direction. Above a certain threshold of subglottal pressure (or stimulation to the recurrent laryngeal nerve), an abrupt transition from chest-like to fry-like phonation was observed. Conclusions: The study reports unique, quantitative data regarding the Medial Surface dynamics of an in vivo canine vocal fold during phonation, capturing both chest-like and fry-like vibration patterns. These data quantify a complex set of dynamics. The mathematical modeling of such complexity is still in its infancy and requires quantitative data of this nature for development, validation, and testing.
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vocal tract influence on Medial Surface dynamics of the vocal folds
Journal of the Acoustical Society of America, 2004Co-Authors: Michael Doellinger, David A Berry, Douglas W MontequinAbstract:In previous work, quantitative measurement of the Medial Surface dynamics of the vocal folds was reported using a hemilarynx methodology. The technique was applied to excised larynges from both humans and canines, as well as to in vivo canine larynges. In the present investigation, a vocal tract was attached to the excised hemilarynx preparation, and systematic changes were made in vocal tract shape to study its influence on the Medial Surface dynamics. In particular, the width of the epilarynx was varied across experiments. Previously, in a similar experiment, phonation threshold pressure was investigated as a function of epilarynx width. It has also been shown that epilarynx width has an influence on glottal volume velocity and the acoustic output [I. R. Titze and B. H. Story, J. Acoust. Soc. Am. 101, 2234–2243]. However, the direct influence of the epilarynx width on vocal fold vibration has never been quantified. The present investigation considered the impact of epilarynx width on the Medial Surface ...
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Medial Surface dynamics of the vocal folds in an in vivo canine model
Journal of the Acoustical Society of America, 2004Co-Authors: Michael Doellinger, Dinesh K Chhetri, Gerald S Berke, David A BerryAbstract:Quantitative measurement of the Medial Surface dynamics of the vocal folds is important for understanding how sound is generated in the larynx. However, such data are hard to gather because of the inaccessibility of the vocal folds. Recent studies have applied hemi‐larynx methodology to excised human larynges, to visualize these dynamics. The present study extends this methodology to obtain similar quantitative measurements using an in vivo canine hemi‐larynx setup, with varying levels of stimulation to the recurrent laryngeal nerve. Use of an in vivo model allows us to examine effects of intrinsic muscle contraction on the Medial Surface of the vocal folds, to provide greater insight into mechanisms of vocal control. Data were collected using digital high‐speed imaging with a sampling frequency of up to 4000 Hz, and a spatial resolution of up to 1024×1024 pixels. Three‐dimensional motion will be extracted, computed, visualized, and contrasted as a function of the level of stimulation to the recurrent lar...
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quantitative measurements of the Medial Surface of the vocal folds in an in vivo canine model
2004Co-Authors: Michael Doellinger, Gerald S Berke, David A BerryAbstract:Medial Surface dynamics of the vocal folds are important for an understanding of sound generation within the larynx. Such dynamics illustrate the propagation of the mucosal wave which makes voice production possible. Almost universally, in vivo investigations of vocal fold dynamics are performed using endoscopic techniques which allow only a superior view of vocal fold vibration. Hence, the view onto the Medial margin is blocked which leads to an observation leak within the vocal fold cycle. In this study, an excised hemi-larynx set-up, is adapted for use with an in vivo canine model. In vivo models allow us to examine effects of intrinsic muscle contraction on the Medial Surface dynamics of the vocal folds, and provide greater insight into mechanisms of vocal control. Dynamics, of the vocal folds with varying levels of stimulation to the recurrent laryngeal nerve (RLN) will be shown. In particular, quantitative measurements such as fundamental frequency, vocal intensity, and the dynamics of up to 15 different positions along the Medial Surface of the vocal folds will be presented as a function of RLN innervation. To capture the vibrations, the vocal folds were imaged with a sampling frequency of 2000 Hz, and a spatial resolution of 1024 x 1024 pixels
Zhaoyan Zhang - One of the best experts on this subject based on the ideXlab platform.
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voice production in a mri based subject specific vocal fold model with parametrically controlled Medial Surface shape
Journal of the Acoustical Society of America, 2019Co-Authors: Liang Wu, Zhaoyan ZhangAbstract:The goal of this study was to investigate how realistic changes in Medial Surface shape, as occur in human phonation, affect voice production. In a parametric magnetic resonance imaging-based three-dimensional vocal fold model, the superior and inferior portions of the Medial Surface were systematically manipulated to produce different Medial Surface contours similar to those observed in previous excised larynx and in vivo canine larynx experiments. Voice simulations were performed to investigate the differences in the resulting voice production. The results showed that both superior-Medial bulging and inferior-Medial bulging of the Medial Surface, which led to an increased vertical thickness and a more rectangular glottal configuration, increased the closed quotient of vocal fold vibration. Changes in Medial Surface shape also had significant effects on the phonation threshold pressure. The degree of these effects of changes in Medial Surface shape was larynx specific, and varied significantly depending on the vocal fold cross-sectional geometry and its variation along the anterior-posterior direction. The results suggest that, in addition to vocal fold approximation, surgical interventions of voice disorders should also aim at restoring a rectangular and sufficiently thick Medial Surface.The goal of this study was to investigate how realistic changes in Medial Surface shape, as occur in human phonation, affect voice production. In a parametric magnetic resonance imaging-based three-dimensional vocal fold model, the superior and inferior portions of the Medial Surface were systematically manipulated to produce different Medial Surface contours similar to those observed in previous excised larynx and in vivo canine larynx experiments. Voice simulations were performed to investigate the differences in the resulting voice production. The results showed that both superior-Medial bulging and inferior-Medial bulging of the Medial Surface, which led to an increased vertical thickness and a more rectangular glottal configuration, increased the closed quotient of vocal fold vibration. Changes in Medial Surface shape also had significant effects on the phonation threshold pressure. The degree of these effects of changes in Medial Surface shape was larynx specific, and varied significantly depending ...
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effect of Medial Surface shape on voice production in a mri based three dimensional phonation model
Journal of the Acoustical Society of America, 2019Co-Authors: Liang Wu, Zhaoyan ZhangAbstract:Our previous studies using simplified vocal fold geometry have shown that Medial Surface shape, particularly the vertical thickness, has an important effect on the closure pattern of vocal fold vibration. The goal of this study is to investigate if similar effect can be observed for Medial Surface shape that occurs in realistic human phonation, using a parametric MRI-based three-dimensional vocal fold model. Manipulation of Medial Surface shape is achieved through a two-level control of the superior and inferior portion of the Medial Surface, based on experimental observations. Simulations show that, in general, both superior-Medial bulging and inferior-Medial bulging of the Medial Surface, which leads to an increased vertical thickness and a more rectangular glottal configuration, increase the closed quotient of the vocal fold vibration. Changes in Medial Surface shape also have significant effect on the phonation threshold pressure. This effect of the Medial Surface shape varies significantly across larynges, indicating the important effect of subject-specific laryngeal geometry. The results point to the importance of taking into consideration of the Medial Surface shape in clinical management of voice disorders. [Work supported by NIH.]Our previous studies using simplified vocal fold geometry have shown that Medial Surface shape, particularly the vertical thickness, has an important effect on the closure pattern of vocal fold vibration. The goal of this study is to investigate if similar effect can be observed for Medial Surface shape that occurs in realistic human phonation, using a parametric MRI-based three-dimensional vocal fold model. Manipulation of Medial Surface shape is achieved through a two-level control of the superior and inferior portion of the Medial Surface, based on experimental observations. Simulations show that, in general, both superior-Medial bulging and inferior-Medial bulging of the Medial Surface, which leads to an increased vertical thickness and a more rectangular glottal configuration, increase the closed quotient of the vocal fold vibration. Changes in Medial Surface shape also have significant effect on the phonation threshold pressure. This effect of the Medial Surface shape varies significantly across lar...
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effect of changes in Medial Surface shape on voice production in excised human larynges
Journal of the Acoustical Society of America, 2019Co-Authors: Zhaoyan Zhang, Dinesh K ChhetriAbstract:Clinical intervention of glottal insufficiency often focuses on correcting glottal gap as visualized from above. In contrast, changes in Medial Surface shape due to intervention have received less attention. This study investigated how changes in Medial Surface shape affect voice production in excised human larynges, by locally Medializing the Medial Surface at different longitudinal and vertical locations. The results showed that localized Medialization at a more inferior location yielded better improvement in glottal closure and higher-order harmonic excitation in the produced voice. This study shows that surgical intervention of glottal insufficiency should also aim at restoring desirable Medial Surface shape.
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the importance of Medial Surface vertical thickness to the control of voice production
Journal of the Acoustical Society of America, 2018Co-Authors: Zhaoyan ZhangAbstract:While vocal fold vibration is often studied from a superior view, the vertical thickness of the vocal fold Medial Surface (or the portion that forms the glottal constriction) has long been hypothesized to play an important role in the control of voice production. This importance of the vertical thickness is confirmed in our recent computational studies, which showed that the vertical thickness, not the degree of vocal fold approximation, has a dominant effect on the vocal fold contact pattern and the spectral shape of the produced voice. Specifically, thicker folds often vibrate with a larger closed quotient, a lower H1-H2 value, and stronger excitation of higher-order harmonics. Thicker folds are also more likely to exhibit irregular vibration. These studies also showed an important effect of the transverse stiffness of the vocal fold in the coronal plane on the resulting voice quality, but a relatively small effect of the longitudinal tension on voice quality except around phonation onset. These results suggest that in addition to the superior view, more attention should be given to vocal fold shape along the vertical dimension and its control. [Work supported by NIH grant R01DC011299.]While vocal fold vibration is often studied from a superior view, the vertical thickness of the vocal fold Medial Surface (or the portion that forms the glottal constriction) has long been hypothesized to play an important role in the control of voice production. This importance of the vertical thickness is confirmed in our recent computational studies, which showed that the vertical thickness, not the degree of vocal fold approximation, has a dominant effect on the vocal fold contact pattern and the spectral shape of the produced voice. Specifically, thicker folds often vibrate with a larger closed quotient, a lower H1-H2 value, and stronger excitation of higher-order harmonics. Thicker folds are also more likely to exhibit irregular vibration. These studies also showed an important effect of the transverse stiffness of the vocal fold in the coronal plane on the resulting voice quality, but a relatively small effect of the longitudinal tension on voice quality except around phonation onset. These results...
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Hirano's cover-body model and its unique laryngeal postures revisited.
Laryngoscope, 2017Co-Authors: Andrew M. Vahabzadeh-hagh, Zhaoyan Zhang, Dinesh K ChhetriAbstract:OBJECTIVES/HYPOTHESIS: In 1974, Minoru Hirano proposed his theory of voice production that is now known as the cover-body theory. He described the thyroarytenoid (TA) and cricothyroid (CT) muscles as the major determinants of vocal fold shape and stiffness, and theorized four typical laryngeal configurations resulting from unique TA/CT activations, with implications for the resulting voice quality. In this study, we directly observed the vocal fold Medial Surface shape under Hirano's unique TA/CT activation conditions to obtain a three-dimensional (3D) understanding of these laryngeal configurations during muscle activation. STUDY DESIGN: In vivo canine hemilarynx model. METHODS: Flesh points were marked along the Medial Surface of the vocal fold. Selective TA and CT activation were performed via respective laryngeal nerves. 3D reconstructions of the vocal fold Medial Surface were derived using digital image correlation. RESULTS: Low level TA and CT activation yielded anteroposterior lengthening and vertical thinning of the vocal fold. When TA activation is far greater than CT, the vocal fold shortens and thickens. With slightly greater TA than CT, activation the vocal length is maintained on average, whereas its vertical thickness decreases. With CT far greater than TA activation, the vocal fold lengthens and thins. In all conditions, glottal contour changes remained minimal. CONCLUSIONS: Analysis of the 3D geometry of the vocal fold Medial Surface under Hirano's four typical laryngeal configurations revealed that the key geometric changes during TA/CT interactions lie within the anteroposterior length and the vertical thickness of the vocal fold. LEVEL OF EVIDENCE: NA. Laryngoscope, 128:1412-1418, 2018.
Vahid Taimouri - One of the best experts on this subject based on the ideXlab platform.
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Left ventricle motion classification in the Medial Surface shape space
2013 IEEE 10th International Symposium on Biomedical Imaging, 2013Co-Authors: Vahid TaimouriAbstract:The wall thickness is known as a valuable measure for the cardiac diagnosis. From the geometric point of view, it can be considered as a function defined on the 2D manifold of the Medial Surface. This paper presents a novel classification method based on Medial representation to diagnose and detect the myopathic regions on the left ventricle. A shape space is proposed and constructed based on the changes of the left ventricle wall thickness, in which two shape descriptors are introduced which show remarkable performance to distinguish normal and abnormal left ventricle deformations. The experimental results show that this method can automatically classify the healthy and myopathic subjects and detect myopathic regions on the left ventricle well.
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ISBI - Left ventricle motion classification in the Medial Surface shape space
2013 IEEE 10th International Symposium on Biomedical Imaging, 2013Co-Authors: Vahid TaimouriAbstract:The wall thickness is known as a valuable measure for the cardiac diagnosis. From the geometric point of view, it can be considered as a function defined on the 2D manifold of the Medial Surface. This paper presents a novel classification method based on Medial representation to diagnose and detect the myopathic regions on the left ventricle. A shape space is proposed and constructed based on the changes of the left ventricle wall thickness, in which two shape descriptors are introduced which show remarkable performance to distinguish normal and abnormal left ventricle deformations. The experimental results show that this method can automatically classify the healthy and myopathic subjects and detect myopathic regions on the left ventricle well.
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Visualization of Shape Motions in Shape Space
IEEE Transactions on Visualization and Computer Graphics, 2013Co-Authors: Vahid TaimouriAbstract:Analysis of dynamic object deformations such as cardiac motion is of great importance, especially when there is a necessity to visualize and compare the deformation behavior across subjects. However, there is a lack of effective techniques for comparative visualization and assessment of a collection of motion data due to its 4-dimensional nature, i.e., timely varying three-dimensional shapes. From the geometric point of view, the motion change can be considered as a function defined on the 2D manifold of the Surface. This paper presents a novel classification and visualization method based on a Medial Surface shape space, in which two novel shape descriptors are defined, for discriminating normal and abnormal human heart deformations as well as localizing the abnormal motion regions. In our Medial Surface shape space, the geodesic distance connecting two points in the space measures the similarity between their corresponding Medial Surfaces, which can quantify the similarity and disparity of the 3D heart motions. Furthermore, the novel descriptors can effectively localize the inconsistently deforming myopathic regions on the left ventricle. An easy visualization of heart motion sequences on the projected space allows users to distinguish the deformation differences. Our experimental results on both synthetic and real imaging data show that this method can automatically classify the healthy and myopathic subjects and accurately detect myopathic regions on the left ventricle, which outperforms other conventional cardiac diagnostic methods.