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.

Vibration Characteristics of the Vocal Folds

2006 ◽  
Author(s):  
L. Hai ◽  
A. M. Al-Jumaily ◽  
A. Mirnajafi
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Vocal Fold ◽  
Vocal Folds ◽  
Element Model ◽  
Vibration Characteristics ◽  
Transverse Isotropic ◽  
Body Theory ◽  
Oscillation Characteristics ◽  
Vocal Fold Nodules

The vibration characteristics of the vocal folds are investigated using a finite element model which incorporates the in-homogeneity and anisotropy of the materials and the irregularity of the geometry. The model employs the cover and body theory to build the structure of the vocal folds and implements measured viscoelastic properties of the mucosa and the transverse isotropic elastic properties of the muscles. It has the potential to simulate some vocal-fold disorders and determine the change in characteristics. To determine the oscillation characteristics of the folds, the eigenfrequency and eigenmodes of the finite element model are determined using the ABAQUS software. The model results compare well with some experiments performed on a silicon vocal fold. It is anticipated that the model will help to identify voice disorders such as vocal-fold paralysis and vocal-fold nodules.

scholarly journals Bayesian Inference of Vocal Fold Material Properties from Glottal Area Waveforms Using a 2D Finite Element Model

2019 ◽  
Vol 9 (13) ◽  
pp. 2735 ◽  
Author(s):  
Paul J. Hadwin ◽  
Mohsen Motie-Shirazi ◽  
Byron D. Erath ◽  
Sean D. Peterson
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bayesian Estimation ◽  
Material Properties ◽  
Vocal Fold ◽  
Vocal Folds ◽  
Element Model ◽  
Lumped Element ◽  
Subglottal Pressure ◽  
Contact Pressures

Bayesian estimation has been previously demonstrated as a viable method for developing subject-specific vocal fold models from observations of the glottal area waveform. These prior efforts, however, have been restricted to lumped-element fitting models and synthetic observation data. The indirect relationship between the lumped-element parameters and physical tissue properties renders extracting the latter from the former difficult. Herein we propose a finite element fitting model, which treats the vocal folds as a viscoelastic deformable body comprised of three layers. Using the glottal area waveforms generated by self-oscillating silicone vocal folds we directly estimate the elastic moduli, density, and other material properties of the silicone folds using a Bayesian importance sampling approach. Estimated material properties agree with the “ground truth” experimental values to within 3 % for most parameters. By considering cases with varying subglottal pressure and medial compression we demonstrate that the finite element model coupled with Bayesian estimation is sufficiently sensitive to distinguish between experimental configurations. Additional information not available experimentally, namely, contact pressures, are extracted from the developed finite element models. The contact pressures are found to increase with medial compression and subglottal pressure, in agreement with expectation.

A finite-element model of vocal-fold vibration

2000 ◽  
Vol 108 (6) ◽  
pp. 3003-3012 ◽  
Author(s):  
Fariborz Alipour ◽  
David A. Berry ◽  
Ingo R. Titze
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Vocal Fold ◽  
Element Model ◽  
Vocal Fold Vibration

Vocal Fold Dynamics During Phonations

2007 ◽  
Author(s):  
H. Lan ◽  
A. M. Al-Jumaily ◽  
A. Mirnajafi
Keyword(s):  
Finite Element ◽  
Risk Factor ◽  
Finite Element Model ◽  
Vocal Fold ◽  
Vocal Folds ◽  
Element Model ◽  
Glottal Closure ◽  
Vocal Fold Dynamics ◽  
The Impact ◽  
The Finite Element Model

During phonation, the vocal folds collision in the glottal closure is considered as a risk factor for pathology development. Based on the finite element model using the software ABAQUS™, the impact stresses between the vocal folds are studied.

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.

scholarly journals Factors Affecting the Severity of Placental Abruption in Pregnant Vehicle Drivers: Analysis with a Novel Finite Element Model

Healthcare ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 27
Author(s):  
Katsunori Tanaka ◽  
Yasuki Motozawa ◽  
Kentaro Takahashi ◽  
Tetsuo Maki ◽  
Masahito Hitosugi
Keyword(s):  
Finite Element ◽  
Pregnant Woman ◽  
Finite Element Model ◽  
Placental Abruption ◽  
Motor Vehicle ◽  
Human Subjects ◽  
Element Model ◽  
Collision Velocity ◽  
Vehicle Collisions ◽  
Factors Affecting

We clarified factors affecting the severity of placental abruption in motor vehicle collisions by quantitively analyzing the area of placental abruption in a numerical simulation of an unrestrained pregnant vehicle driver at collision velocities of 3 and 6 m/s. For the simulation, we constructed a novel finite element model of a small 30-week pregnant woman, which was validated anthropometrically using computed tomography data and biomechanically using previous examinations of post-mortem human subjects. In the simulation, stress in the elements of the utero–placental interface was computed, and those elements exceeding a failure criterion were considered to be abrupted. It was found that a doubling of the collision velocity increased the area of placental abruption 10-fold, and the abruption area was approximately 20% for a collision velocity of 6 m/s, which is lower than the speed limit for general roads. This result implies that even low-speed vehicle collisions have negative maternal and fetal outcomes owing to placental abruption without a seatbelt restraint. Additionally, contact to the abdomen, 30 mm below the umbilicus, led to a larger placental abruption area than contact at the umbilicus level when the placenta was located at the uterus fundus. The results support that a reduction in the collision speed and seatbelt restraint at a suitable position are important to decrease the placental abruption area and therefore protect a pregnant woman and her fetus in a motor vehicle collision.

Sign in / Sign up

Export Citation Format

Share Document