scholarly journals Effects of Vertical Glottal Duct Length on Intraglottal Pressures in the Convergent Glottis

2021 ◽  
Vol 11 (10) ◽  
pp. 4535
Author(s):  
Sheng Li ◽  
Ronald C. Scherer ◽  
Mingxi Wan
Keyword(s):  
Vocal Fold ◽  
Pressure Coefficient ◽  
Vocal Folds ◽  
Physical Models ◽  
Ansys Fluent ◽  
Vocal Fold Vibration ◽  
Pressure Distributions ◽  
Two Dimensional Flow ◽  
Aerodynamic Parameters ◽  
Opening Phase

In a previous study, the vertical glottal duct length was examined for its influence on intraglottal pressures and other aerodynamic parameters in the uniform glottis [J Voice 32, 8–22 (2018)]. This study extends that work for convergent glottal angles, the shape of the glottis during the glottal opening phase of vocal fold vibration. The computational fluid dynamics code ANSYS Fluent 6.3 was used to obtain the pressure distributions and other aerodynamic parameters for laminar, incompressible, two-dimensional flow in a static vocal fold model. Four typical vertical glottal duct lengths (0.108, 0.308, 0.608, 0.908 cm) were selected for three minimal diameters (0.01, 0.04, 0.16 cm), three transglottal pressures (500, 1000, 1500 Pa), and three convergent glottal angles (−5°, −10°, −20°). The results suggest that a longer vertical glottal duct length increases the intraglottal pressures, decreases the glottal entrance loss coefficient, increases the transglottal pressure coefficient, causes a lower gradient of both the intraglottal flow velocity and the wall shear stress along the glottal wall—especially for low flows and small glottal minimal diameters—and has little effect on the exit pressure coefficient and volume flow. The vertical glottal duct length in the convergent glottis has important effects on phonation and should be well specified when building computational and physical models of the vocal folds.

Reinke's Edema: Phonatory Mechanisms and Management Strategies

1997 ◽  
Vol 106 (7) ◽  
pp. 533-543 ◽  
Author(s):  
Steven M. Zeitels ◽  
Glenn W. Bunting ◽  
Robert E. Hillman ◽  
Traci Vaughn
Keyword(s):  
Lamina Propria ◽  
Fundamental Frequency ◽  
Vocal Fold ◽  
Management Strategies ◽  
Vocal Folds ◽  
Vocal Fold Vibration ◽  
Reinke’S Edema ◽  
Subglottal Pressure ◽  
Almost All ◽  
Superficial Lamina

Reinke's edema (RE) has been associated typically with smoking and sometimes with vocal abuse, but aspects of the pathophysiology of RE remain unclear. To gain new insights into phonatory mechanisms associated with RE pathophysiology, weused an integrated battery of objective vocal function tests to analyze 20 patients (19 women) who underwent phonomicrosurgical resection. Preoperative stroboscopic examinations demonstrated that the superficial lamina propria is distended primarily on the superior vocal fold surface. Acoustically, these individuals have an abnormally low average speaking fundamental frequency (123 Hz), and they generate abnormally high average subglottal pressures (9.7 cm H20). The presence of elevated aerodynamic driving pressures reflects difficulties in producing vocal fold vibration that are most likely the result of mass loading associated with RE, and possibly vocal hyperfunction. Furthermore, it is hypothesized that in the environment of chronic glottal mucositis secondary to smoking and reflux, the cephalad force on the vocal folds by the subglottal driving pressure contributes to the superior distention of the superficial lamina propria. Surgical reduction of the volume of the superficial lamina propria resulted in a significant elevation in fundamental frequency (154 Hz) and improvement in perturbation measures. In almost all instances, both the clinician and the patient perceived the voice as improved. However, these patients continued to generate elevated subglottal pressure (probably a sign of persistent hyperfunction) that was accompanied by visually observed supraglottal strain despite the normalsized vocal folds. This finding suggests that persistent hyperfunctional vocal behaviors may contribute to postsurgical RE recurrence if therapeutic strategies are not instituted to modify such behavior.

Effects of Voice Therapy as Objectively Evaluated by Digitized Laryngeal Stroboscopic Imaging

2002 ◽  
Vol 111 (10) ◽  
pp. 902-908 ◽  
Author(s):  
Renée Speyer ◽  
Pieter A. Kempen ◽  
George Wieneke ◽  
Willem Kersing ◽  
Elham Ghazi Hosseini ◽  
...  
Keyword(s):  
Vocal Fold ◽  
Vocal Folds ◽  
Lesion Size ◽  
Voice Therapy ◽  
Benign Lesions ◽  
Objective Measurements ◽  
Significant Parameter ◽  
Surface Areas ◽  
Vocal Fold Vibration ◽  
Maximal Opening

Objective measurements derived from digitized laryngeal stroboscopic images were used to demonstrate changes in vocal fold vibration and in the size of benign lesions after 3 months of voice therapy. Forty chronically dysphonic patients were studied. By means of a rigid stroboscope, pretreatment and posttreatment recordings were made of the vocal folds at rest and under stroboscopic light during phonation. From each recording, images of the positions at rest and during vibration at maximal opening and at maximal closure were digitized. The surface areas of any lesions and of the glottal gap were independently measured in the digitized images by 2 experienced laryngologists. Referential distances were determined in order to compensate for discrepancies in magnification in the various recordings. After 3 months of voice therapy, significant improvement in lesion size and degree of maximal closure during vibration could be demonstrated in about 50% of the patients. The degree of maximal opening did not prove to be a significant parameter.

Videostrobolaryngoscopy of Mucus Layer during Vocal Fold Vibration in Patients with Laryngeal Tension-Fatigue Syndrome

2002 ◽  
Vol 111 (6) ◽  
pp. 537-541 ◽  
Author(s):  
Tzu-Yu Hsiao ◽  
Chia-Ming Liu ◽  
Kai-Nan Lin
Keyword(s):  
Mechanical Properties ◽  
Vocal Fold ◽  
Rough Surfaces ◽  
Voice Disorders ◽  
Vocal Folds ◽  
Voice Disorder ◽  
Mucus Layer ◽  
Vocal Fold Vibration ◽  
Fatigue Syndrome ◽  
Functional Dysphonia

The mucus layer on the vocal folds was examined by videostrobolaryngoscopy in patients with laryngeal tension-fatigue syndrome, a chronic functional dysphonia due to vocal abuse and misuse. Besides the findings in previous reports (such as abnormal glottal closure, phase or amplitude asymmetry, and the irregular mucosal wave), the vocal folds during vibration had an uneven mucus surface. The occurrence of an uneven mucus layer on vocal folds was significantly greater in subjects with this voice disorder (83% or 250 of 301 patients in this series) than in those without voice disorders (18.5% or 5 of 27). The increase of mucus viscosity, mucus aggregation, and the formation of rough surfaces on the vocal folds alter the mechanical properties that contribute to vibration of the cover of the vocal folds, and thereby worsen the symptoms of dysphonia in patients with laryngeal tension-fatigue syndrome.

Finite Element Modeling of Vocal Fold Vibration in Normal Phonation and Hyperfunctional Dysphonia: Implications for the Pathogenesis of Vocal Nodules

1998 ◽  
Vol 107 (7) ◽  
pp. 603-610 ◽  
Author(s):  
Jack J. Jiang ◽  
Carlos E. Diaz ◽  
David G. Hanson
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Mechanical Stress ◽  
Vocal Fold ◽  
Vocal Folds ◽  
Element Modeling ◽  
Modeling Technology ◽  
Vocal Fold Vibration ◽  
Vocal Nodules ◽  
High Mechanical Stress

A computer model of the vocal fold was developed using finite element modeling technology for studying mechanical stress distribution over vibrating vocal fold tissue. In a simulated normal phonation mode, mechanical stress was found to be lowest at the midpoint of the vocal fold and highest at tendon attachments. However, when other modes predominated, high mechanical stress could occur at the midpoint of the vocal folds. When a vocal fold mass was modeled, high shearing stress occurred at the base of the modeled vocal fold mass, suggesting that the presence of a vocal nodule or polyp is associated with high mechanical stress at the margins of the mass. This finding supports a hypothesis that mechanical intraepithelial stress plays an important role in the development of vocal nodules, polyps, and other lesions that are usually ascribed to hyperfunctional dysphonia.

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.

Nonlinear behavior of vocal fold vibration: The role of coupling between the vocal folds

1999 ◽  
Vol 13 (4) ◽  
pp. 465-476 ◽  
Author(s):  
Antoine Giovanni ◽  
Maurice Ouaknine ◽  
Bruno Guelfucci ◽  
Ping Yu ◽  
Michel Zanaret ◽  
...  
Keyword(s):  
Vocal Fold ◽  
Nonlinear Behavior ◽  
Vocal Folds ◽  
Vocal Fold Vibration

A Study of Vocal Fold Vibration Using a Slightly Compressible Fluid Domain

2009 ◽  
Author(s):  
D. J. Daily ◽  
S. L. Thomson
Keyword(s):  
Boundary Conditions ◽  
Incompressible Fluid ◽  
Compressible Fluid ◽  
Vocal Fold ◽  
Computational Models ◽  
Fluid Model ◽  
Vocal Folds ◽  
Moving Wall ◽  
Slightly Compressible ◽  
Vocal Fold Vibration

During human voice production, air forced from the lungs through the larynx induces vibration of the vocal folds. Computational models of this coupled fluid-solid system have traditionally utilized an incompressible fluid domain. However, studies have shown that coupling of tracheal acoustics with vocal fold dynamics is significant. Further, in the absence of compressibility, some models fail to achieve self-sustained vibration. This presentation discusses a slightly compressible airflow model, fully coupled with a vocal fold tissue model, as a possible substitute for the traditional incompressible approach. The derivation and justification of the slightly compressible fluid model are discussed. Results are reported of a study of the nature of the coupling between the fluid and vocal fold regions for both slightly compressible and incompressible fluid domains using a commercial fluid-solid finite element package. Three different types of inlet boundary conditions, including constant pressure, constant velocity, and moving wall, are explored. The incompressible and slightly compressible models with the three boundary conditions are compared with each other and with experimental data obtained using synthetic self-oscillating vocal fold models. The results are used to validate the slightly compressible flow model as well as to explore candidate boundary conditions for vocal fold vibration simulations.

Measurement of Young's Modulus in the in Vivo Human Vocal Folds

1993 ◽  
Vol 102 (8) ◽  
pp. 584-591 ◽  
Author(s):  
Quang T. Tran ◽  
Bruce R. Gerratt ◽  
Gerald S. Berke ◽  
Jody Kreiman
Keyword(s):  
Recurrent Laryngeal Nerve ◽  
Young’S Modulus ◽  
Nerve Stimulation ◽  
Vocal Fold ◽  
Young's Modulus ◽  
Vocal Folds ◽  
Laryngeal Nerve ◽  
New Device ◽  
Vocal Fold Vibration

Currently, surgeons have no objective means to evaluate and optimize results of phonosurgery intraoperatively. Instead, they usually judge the vocal folds subjectively by visual inspection or by listening to the voice. This paper describes a new device that measures Young's (elastic) modulus values for the human vocal fold intraoperatively. Physiologically, the modulus of the vocal fold may be important in determining the nature of vocal fold vibration in normal and pathologic states. This study also reports the effect of recurrent laryngeal nerve stimulation on Young's modulus of the human vocal folds, measured by means of transcutaneous nerve stimulation techniques. Young's modulus increased with increases in current stimulation to the recurrent laryngeal nerve. Ultimately, Young's modulus values may assist surgeons in optimizing the results of various phonosurgeries.

Human Vocalis Contains Distinct Superior and Inferior Subcompartments: Possible Candidates for the Two Masses of Vocal Fold Vibration

1998 ◽  
Vol 107 (10) ◽  
pp. 826-833 ◽  
Author(s):  
Ira Sanders ◽  
Yingshi Han ◽  
Surinder Rai ◽  
Hugh F. Biller
Keyword(s):  
Vocal Fold ◽  
Muscle Fibers ◽  
Vocal Folds ◽  
Medial Surface ◽  
Vocal Fold Vibration ◽  
Muscle Fascicle ◽  
Superior Surface ◽  
Hematoxylin And Eosin ◽  
Thyroarytenoid Muscle ◽  
Large Muscle

It is not understood how different parts of the thyroarytenoid muscle contribute to vocal fold vibration. This study investigated the medial part of the thyroarytenoid muscle, the vocalis compartment, for anatomic differences that might suggest functionally distinct areas. Twenty human vocal folds were frontally sectioned and stained with hematoxylin and eosin. A single section from the middle of each vocal fold was magnified, and the muscle fascicles of the most superficial 25% of the vocalis compartment were then examined. In all 20 specimens the vocalis compartment could be separated into 2 plainly distinct subcompartments: the inferior vocalis compartment was composed of a single large muscle fascicle that contained densely packed muscle fibers of similar size; the superior vocalis compartment was composed of multiple small fascicles in which the muscle fibers were loosely arranged and varied greatly in size. On average, the inferior vocalis subcompartment composed 60% of the medial surface of the thyroarytenoid muscle. The superior subcompartment composed the remaining 40% of the medial surface, but also continued past the vocal ligament to make up the superior surface of the thyroarytenoid muscle. It is concluded that 2 distinct entities make up the vocalis compartment of the thyroarytenoid muscle. Their anatomy is so markedly different it suggests that they may function independently. One possibility is that they reflect the 2 masses observed in the superior and inferior aspects of the vocal fold during vibration.

Influence of Vocal Fold Scarring on Phonation: Predictions from a Finite Element Model

2005 ◽  
Vol 114 (11) ◽  
pp. 847-852 ◽  
Author(s):  
David A. Berry ◽  
Haven Reininger ◽  
Fariborz Alipour ◽  
Diane M. Bless ◽  
Charles N. Ford
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Fundamental Frequency ◽  
Viscoelastic Properties ◽  
Vocal Fold ◽  
Human Subjects ◽  
Vocal Folds ◽  
Element Model ◽  
Acoustic Intensity ◽  
Vocal Fold Vibration

Objectives: A systematic study of the influence of vocal fold scarring on phonation was conducted. In particular, phonatory variables such as fundamental frequency, oral acoustic intensity, and phonation threshold pressure (PTP) were investigated as a function of the size and position of the laryngeal scar. Methods: By means of a finite element model of vocal fold vibration, the viscoelastic properties of both normal and scarred vocal fold mucosae were simulated on the basis of recent rheological data obtained from rabbit and canine models. Results: The study showed that an increase in the viscoelasticity of the scarred mucosa resulted in an increase in fundamental frequency, an increase in PTP, and a decrease in oral acoustic intensity. With regard to positioning of the scar, the PTP increased most significantly when the scar was within ±2 mm of the superior-medial junction of the vocal folds. Conclusions: The systematic data obtained in this investigation agree with the general clinical experience. In the future, these findings may be further validated on human subjects as newly emerging technologies such as linear skin rheometry and optical coherence tomography allow the histologic and viscoelastic properties of the normal and scarred vocal fold mucosae to be measured in the clinic.

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