A New Biomechanical Model of Vocal Fold Vibrations: Preliminary Experimental Validation

2011 ◽  
Author(s):  
Zhenyi Wei ◽  
Marcio de Queiroz ◽  
Jing Chen ◽  
Bahadir K. Gunturk ◽  
Melda Kunduk
Keyword(s):  
Vocal Fold ◽  
High Speed ◽  
Model Comparison ◽  
Model Simulation ◽  
Biomechanical Model ◽  
Vocal Folds ◽  
The Body ◽  
Cover Layer ◽  
Proposed Model ◽  
Time Domains

This paper introduces a new seven-mass biomechanical model for the vibration of vocal folds. The model is based on the body-cover layer concept of the vocal fold biomechanics, and segments the cover layer into three masses. This segmentation facilitates the model comparison with the motion of the vocal glottis contour derived from modern high-speed digital imaging systems. The model simulation is compared to experimental data from a pair of healthy vocal folds showing good agreement in the frequency and time domains. The proposed model is also shown to outperform a previously-developed model that does not explicitly account for the body layer dynamics.

Normal Voice Production: Computation of Driving Parameters from Endoscopic Digital High Speed Images

2003 ◽  
Vol 42 (03) ◽  
pp. 271-276 ◽  
Author(s):  
T. Braunschweig ◽  
J. Lohscheller ◽  
U. Eysholdt ◽  
U. Hoppe ◽  
M. Döllinger
Keyword(s):  
Vocal Fold ◽  
High Speed ◽  
Biomechanical Model ◽  
Vocal Folds ◽  
Inversion Algorithm ◽  
Knowledge Based ◽  
Normal Voice ◽  
Inversion Procedure ◽  
High Speed Glottography

Summary Objectives: A central point for quantitative evaluation of pathological and healthy voices is the analysis of vocal fold oscillations. By means of digital High Speed Glottography (HGG), vocal fold oscillations can be recorded in real time. Recently, a numerical inversion procedure was developed that allows the extraction of physiological parameters from digital high speed videos and a classification of voice disorders. The aim of this work was to validate the inversion procedure and to investigate the applicability to normal voices. Methods: High speed recordings were performed during phonation within a group of five female and five male persons with normal voices. By using knowledge based image processing algorithms, motion curves of the vocal folds were extracted at three different positions (dorsal, medial, ventral). These curves were used to obtain physiological voice parameters, and in particular the degree of symmetry of the vocal folds based upon a biomechanical model of the vocal folds. Results: The highest degree of symmetry was observed for the medial motion curves. While the dor-sally and ventrally extracted motion curves exhibited similar results concerning the degree of symmetry the performance of the algorithm was less stable. Conclusions: The inversion algorithm provides reasonable results for all subjects when applied to the medial motion curves. However, for dorsal and ventral motion curves, correct performance is reduced to 85 %.

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

2014 ◽  
Vol 57 (2) ◽  
pp. 416-425 ◽  
Author(s):  
Yue Xuan ◽  
Zhaoyan Zhang
Keyword(s):  
Vocal Fold ◽  
High Speed ◽  
Critical Role ◽  
Structural Features ◽  
The Body ◽  
Baseline Model ◽  
Cover Layer ◽  
Glottal Closure ◽  
Posterior Direction ◽  
Anterior Posterior

Purpose The purpose of this study was 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 2 features. Phonation tests were performed with both aerodynamic and acoustic measurements and high-speed imaging of vocal fold vibration. Results Compared with 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. The presence of fibers in the body layer did not yield noticeable improvements in glottal closure or harmonic excitation. Conclusion 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.

High-Speed Imaging to Study an Auto-Oscillating Vocal Fold Replica for Different Initial Conditions

2017 ◽  
Vol 09 (05) ◽  
pp. 1750064 ◽  
Author(s):  
A. Van Hirtum ◽  
X. Pelorson
Keyword(s):  
Vocal Fold ◽  
High Speed ◽  
Initial Conditions ◽  
Vocal Folds ◽  
High Speed Imaging ◽  
Human Voice ◽  
Manual Intervention ◽  
Geometrical Features ◽  
Upstream Pressure

Experiments on mechanical deformable vocal folds replicas are important in physical studies of human voice production to understand the underlying fluid–structure interaction. At current date, most experiments are performed for constant initial conditions with respect to structural as well as geometrical features. Varying those conditions requires manual intervention, which might affect reproducibility and hence the quality of experimental results. In this work, a setup is described which allows setting elastic and geometrical initial conditions in an automated way for a deformable vocal fold replica. High-speed imaging is integrated in the setup in order to decorrelate elastic and geometrical features. This way, reproducible, accurate and systematic measurements can be performed for prescribed initial conditions of glottal area, mean upstream pressure and vocal fold elasticity. Moreover, quantification of geometrical features during auto-oscillation is shown to contribute to the experimental characterization and understanding.

scholarly journals A Two Joint Neck Model to Identify Malposition of the Head Relative to the Thorax

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3297
Author(s):  
Philipp M. Schmid ◽  
Christoph M. Bauer ◽  
Markus J. Ernst ◽  
Bettina Sommer ◽  
Lars Lünenburger ◽  
...  
Keyword(s):  
Neck Pain ◽  
Body Height ◽  
Biomechanical Model ◽  
The Body ◽  
Head Orientation ◽  
Neck Length ◽  
Proposed Model ◽  
Biofeedback System ◽  
Simple Measurement ◽  
The Impact

Neck pain is a frequent health complaint. Prolonged protracted malpositions of the head are associated with neck pain and headaches and could be prevented using biofeedback systems. A practical biofeedback system to detect malpositions should be realized with a simple measurement setup. To achieve this, a simple biomechanical model representing head orientation and translation relative to the thorax is introduced. To identify the parameters of this model, anthropometric data were acquired from eight healthy volunteers. In this work we determine (i) the accuracy of the proposed model when the neck length is known, (ii) the dependency of the neck length on the body height, and (iii) the impact of a wrong neck length on the models accuracy. The resulting model is able to describe the motion of the head with a maximum uncertainty of 5 mm only. To achieve this high accuracy the effective neck length must be known a priory. If however, this parameter is assumed to be a linear function of the palpable neck length, the measurement error increases. Still, the resulting accuracy can be sufficient to identify and monitor a protracted malposition of the head relative to the thorax.

Dynamic Digital Image Correlation of a Dynamic Physical Model of the Vocal Folds

2005 ◽  
Author(s):  
S. Mantha ◽  
L. Mongeau ◽  
T. Siegmund
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Vocal Fold ◽  
High Speed ◽  
Vocal Folds ◽  
Image Correlation ◽  
Strain Component ◽  
Medial Surface ◽  
Superior Surface ◽  
Incomplete Closure

An experimental study of the vibratory deformation of the human vocal folds was conducted. Experiments were performed using model vocal folds [1, 2], Fig. 1, made of silicone rubber implemented into an air supply system, Fig. 2. The material used to cast the model is an isotropic homogeneous material, [3] with a tangent modulus E=5 kPa at ε = 0, i.e. elastic properties similar to those of the human vocal fold cover [4]. The advantages of the use of model larynx systems over the use of excised larynges include easy accessibility to fundamental studies of the vocal fold vibration without invasive testing. Acoustic analysis of voice or electroglottography provide certain insight into voice production processes but optical techniques for the study of vocal fold vibrations have drawn considerable attention. Videoendoscopy, stroboscopy, high-speed photography, and kymography have shown to provide a visual impression of vocal fold dynamics but are limited in providing insight into the fundamental deformation processes of the vocal folds. Quantitative measures of deformation have been conducted through micro-suture techniques but are invasive and allows for measurements of only view image points. Laser triangulation is non-invasive but is limited to only one local measurement point. Here, digital image correlation technique with the software VIC 3D [5] is applied. For the experimental set-up see Fig. 2. The analysis consists of (1) stereo correlation to obtain in-plane displacements and (2) stereo triangulation step to obtain out-of-plane deformation. For the stereo correlation images of the object at two different stages of deformation are compared. A point in the image of the undeformed object is matched with the corresponding point in the deformed stage. “Subsets” of digital images are traced via their gray value distribution from the undeformed reference image to the deformed image. The uniqueness of the matching is enabled by the creation of a speckle pattern on the object’s surface. Here, a white pigment is mixed into the silicone rubber and subsequently black enamel paint is sprayed onto the superior surface of the vocal folds. The stereo triangulation requires two images of the object at each stage of deformation. These are obtained in a single CCD frame by placing a beam splitter in the optical axis between camera and object. These images provide a “left” and “right” view of the model larynx. Thus, the deformed shape of the vocal folds can be obtained. The method allows for noninvasive measurement of the full-field displacement fields. Images of the superior surface of the model larynx are obtained by the use of a high speed digital camera with a frame rate of 3000 frames per second allowing for more than 30 image frames for each vibration cycle. For the 3D digital image correlation analysis two images of the object are obtained for each time instance as a beam splitter is placed in the optical axis between the camera and the model larynx. Phonation frequencies and onset pressure are given in Fig. 3, showing that the model larynx behavior is close to actual physiological data. Figs 4(a) and (b) provide superior views of the model larynx at maximum glottal opening and at glottal closure, respectively. As one example of measured strain fields, Figs 5(a) and (b) depict the distributions of the transverse strain component, on the glottal surface in a contour plot on the deformed superior surface. The knowledge of the distribution of this strain component is relevant to the assessment of the impact of vocal fold collision on potential tissue damage. In the position of maximum opening the vocal folds are deformed by a combination of a bulging-type deformation and the opening movement. At this time instance, the transverse strains at the medial surface are found to be negative, an indication of Poisson’s deformation. During the closing stage, vocal folds collide and simultaneously a mode 3 vibration pattern emerges. Closure of the glottal opening is not complete and two incomplete closure areas are formed during the closure stage. These open areas are located at the anterior and posterior ends of the model larynx, see Fig. 4(b). The finding of this type of incomplete closure is agreement with both actual glottal measurements [6] and 3D finite element simulations of [7]. Transverse strains during that stage are now positive and considerably larger that during the opening stage. Finally, Fig. 6 depicts the time evolution of the out of plane displacements along the medial surface for the closing phase and Fig. 7 depicts the maximum values of the longitudinal strain (at the coronal section of the medial surface) in dependence of the flow rate. These examples of measurements indicate that the DIC method is promising for studies of vocal fold dynamics.

Electroglottography and Vocal Fold Physiology

1990 ◽  
Vol 33 (2) ◽  
pp. 245-254 ◽  
Author(s):  
D. G. Childers ◽  
D. M. Hicks ◽  
G. P. Moore ◽  
L. Eskenazi ◽  
A. L. Lalwani
Keyword(s):  
Vocal Fold ◽  
High Speed ◽  
Human Subjects ◽  
Vocal Folds ◽  
Supporting Evidence ◽  
Direct Measurements ◽  
Analysis And Synthesis ◽  
Vocal Fold Motion ◽  
Maximum Opening ◽  
Major Hypothesis

The electroglottogram (EGG) is known to be related to vocal fold motion. A major hypothesis undergoing examination in several research centers is that the EGG is related to the area of contact of the vocal folds. This hypothesis is difficult to substantiate with direct measurements using human subjects. However, other supporting evidence can be offered. For this study we made measurements from synchronized ultra high-speed laryngeal films and from EGG waveforms collected from subjects with normal larynges and patients with vocal disorders. We compare certain features of the EGG waveform to (a) the instant of the opening of the glottis, (b) the instant of the closing of the glottis, and (c) the instant of the maximum opening of the glottis. In addition, we compare both the open quotient and the relative average perturbation measured from the glottal area to that estimated from the EGG. All of these comparisons indicate that vocal fold vibratory characteristics are reflected by features of the EGG waveform. This makes the EGG useful for speech analysis and synthesis as well as for modeling laryngeal behavior. The limitations of the EGG are discussed.

Usefulness of high-speed digital imaging (HSDI) in the diagnosis of oedematous – hypertrophic changes of the larynx in people using voice occupationally

2017 ◽  
Vol 71 (4) ◽  
pp. 19-25 ◽  
Author(s):  
Bożena Kosztyła-Hojna ◽  
Diana Moskal ◽  
Anna Kuryliszyn-Moskal ◽  
Anna Andrzejewska ◽  
Anna Łobaczuk-Sitnik ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Digital Imaging ◽  
Vocal Fold ◽  
High Speed ◽  
Vocal Folds ◽  
Intercellular Spaces ◽  
Vacuolar Degeneration ◽  
Transmission Electron ◽  
Tem Method ◽  
Hypertrophic Changes

Introduction. The aim of the study is the evaluation of the usefulness of High-Speed Digital Imaging (HSDI) in the diagnosis of organic dysphonia in a form of oedematous-hypertrophic changes of vocal fold mucosa, morphologically confirmed by Transmission Electron Microscopy (TEM) method in patients working with voice occupationally. Material and methods. The group consisted of 30 patients working with voice occupationally with oedematous-hypertrophic changes of vocal fold mucosa. Parameters of vocal folds vibrations were evaluated using HSDI technique with a digital HS camera, HRES Endocam Richard Wolf GmbH. The image of vocal folds was recorded with a rate of 4000 frames per second. Postoperative material of the larynx was prepared in a routine way and observed in transmission electron microscope OPTON 900–PC. Results. HSDI technique allows to assess the real vibrations of vocal folds and determine many parameters. The results of TEM in the postoperative material showed destruction of epithelial cells with severe vacuolar degeneration, the enlargement of intercellular spaces and a large number of blood vessels in the stroma, which indicates the presence of oedematous-hypertrophic changes of the larynx. Discussion. The ultrastructural assessment confirm the particular usefulness of HSDI method in the diagnosis of organic dysphonia in a form of oedematous-hypertrophic changes. Key words: High-Speed Digital Imaging, oedematous-hypertrophic changes, vocal fold mucosa, larynx

Simplified Triped Robot for Analysis of Three-Dimensional Gait Generation

2017 ◽  
Vol 29 (3) ◽  
pp. 528-535
Author(s):  
Yoichi Masuda ◽  
◽  
Masato Ishikawa
Keyword(s):  
High Speed ◽  
Force Feedback ◽  
Three Dimensional ◽  
Radial Symmetry ◽  
The Body ◽  
Walking Robots ◽  
Body Structure ◽  
Gait Patterns ◽  
Gait Generation ◽  
Proposed Model

[abstFig src='/00290003/08.jpg' width='230' text='The tripedal robot “Martian petit”' ] Significant efforts to simplify the body structure of multi-legged walking robots have been made over the years. Of these, the Spring-Loaded-Inverted-Pendulum (SLIP) model has been very popular, therefore widely employed in the design of walking robots. In this paper, we develop a SLIP-based tripedal walking robot with a focus on the geometric symmetry of the body structure. The proposed robot possesses a compact, light-weight, and compliant leg modules. These modules are controlled by a distributed control law that consists of decoupled oscillators with only local force feedback. As demonstrated through experiments, the simplified design of the robot makes possible the generation of high-speed dynamic locomotion. Despite the structural simplicity of the proposed model, the generation of several gait-patterns is demonstrated. The proposed minimalistic design approach with radial symmetry simplifies the function of each limb in the three-dimensional gait generation of the robot.

Empirical Eigenfunctions and Medial Surface Dynamics of a Human Vocal Fold

2005 ◽  
Vol 44 (03) ◽  
pp. 384-391 ◽  
Author(s):  
N. Tayama ◽  
D. A. Berry ◽  
M. Döllinger
Keyword(s):  
Vocal Fold ◽  
High Speed ◽  
Computational Models ◽  
Imaging System ◽  
Vocal Folds ◽  
Sustained Oscillation ◽  
Medial Surface ◽  
Physical Mechanisms ◽  
Vocal Fold Vibration ◽  
Modes Of Vibration

Summary 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, flow-induced 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.

Airflow Characterization Combined With 3D Reconstruction of Rabbit Vocal Cord Based on In-Vivo Phonatory Experiments

2020 ◽  
Author(s):  
Zhipeng Lou ◽  
Junshi Wang ◽  
James J. Daniero ◽  
Haibo Dong ◽  
Jinxiang Xi
Keyword(s):  
3D Reconstruction ◽  
Vocal Cord ◽  
Vocal Fold ◽  
High Speed ◽  
3D Model ◽  
Vocal Folds ◽  
Computational Effort ◽  
Immersed Boundary ◽  
Vibration Modes

Abstract In this paper, a numerical approach combined with experiments is employed to characterize the airflow through the vocal cord. Rabbits are used to perform in vivo magnetic resonance imaging (MRI) experiments and the MRI scan data are directly imposed for the three-dimensional (3D) reconstruction of a 3D high-fidelity model. The vibration modes are observed via the in vivo high-speed videoendoscopy (HSVM) technique, and the time-dependent glottal height is evaluated dynamically for the validation of the 3D reconstruction model. 72 sets of rabbit in vivo high-speed recordings are evaluated to achieve the most common vibration mode. The reconstruction is mainly based on MRI data and the HSVM records are supporting and validate the 3D model. A sharp-interface immersed-boundary-method (IBM)-based compressible flow solver is employed to compute the airflow. The primary purpose of the computational effort is to characterize the influence of the vocal folds that applied to the airflow and the airflow-induced phonation. The vocal fold kinematics and the vibration modes are quantified and the vortex structures are analyzed under the influence of vocal folds. The results have shown significant effects of the vocal fold height on the vortex structure, vorticity and velocity. The reconstructed 3D model from this work helps to bring insight into further understanding of the rabbit phonation mechanism. The results provide potential improvement for diagnosis of human vocal fold dysfunction and phonation disorder.

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