scholarly journals Modeling the Pathophysiology of Phonotraumatic Vocal Hyperfunction With a Triangular Glottal Model of the Vocal Folds

2017 ◽  
Vol 60 (9) ◽  
pp. 2452-2471 ◽  
Author(s):  
Gabriel E. Galindo ◽  
Sean D. Peterson ◽  
Byron D. Erath ◽  
Christian Castro ◽  
Robert E. Hillman ◽  
...  

Purpose Our goal was to test prevailing assumptions about the underlying biomechanical and aeroacoustic mechanisms associated with phonotraumatic lesions of the vocal folds using a numerical lumped-element model of voice production. Method A numerical model with a triangular glottis, posterior glottal opening, and arytenoid posturing is proposed. Normal voice is altered by introducing various prephonatory configurations. Potential compensatory mechanisms (increased subglottal pressure, muscle activation, and supraglottal constriction) are adjusted to restore an acoustic target output through a control loop that mimics a simplified version of auditory feedback. Results The degree of incomplete glottal closure in both the membranous and posterior portions of the folds consistently leads to a reduction in sound pressure level, fundamental frequency, harmonic richness, and harmonics-to-noise ratio. The compensatory mechanisms lead to significantly increased vocal-fold collision forces, maximum flow-declination rate, and amplitude of unsteady flow, without significantly altering the acoustic output. Conclusion Modeling provided potentially important insights into the pathophysiology of phonotraumatic vocal hyperfunction by demonstrating that compensatory mechanisms can counteract deterioration in the voice acoustic signal due to incomplete glottal closure, but this also leads to high vocal-fold collision forces (reflected in aerodynamic measures), which significantly increases the risk of developing phonotrauma.

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Jun Yin ◽  
Zhaoyan Zhang

Although it is known vocal fold adduction is achieved through laryngeal muscle activation, it is still unclear how interaction between individual laryngeal muscle activations affects vocal fold adduction and vocal fold stiffness, both of which are important factors determining vocal fold vibration and the resulting voice quality. In this study, a three-dimensional (3D) finite element model was developed to investigate vocal fold adduction and changes in vocal fold eigenfrequencies due to the interaction between the lateral cricoarytenoid (LCA) and thyroarytenoid (TA) muscles. The results showed that LCA contraction led to a medial and downward rocking motion of the arytenoid cartilage in the coronal plane about the long axis of the cricoid cartilage facet, which adducted the posterior portion of the glottis but had little influence on vocal fold eigenfrequencies. In contrast, TA activation caused a medial rotation of the vocal folds toward the glottal midline, resulting in adduction of the anterior portion of the glottis and significant increase in vocal fold eigenfrequencies. This vocal fold-stiffening effect of TA activation also reduced the posterior adductory effect of LCA activation. The implications of the results for phonation control are discussed.


2019 ◽  
Vol 9 (13) ◽  
pp. 2735 ◽  
Author(s):  
Paul J. Hadwin ◽  
Mohsen Motie-Shirazi ◽  
Byron D. Erath ◽  
Sean D. Peterson

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.


2019 ◽  
Vol 9 (21) ◽  
pp. 4671
Author(s):  
Palaparthi ◽  
Smith ◽  
Titze

Any specific vowel sound that humans produce can be represented in terms of four perceptual features in addition to the vowel category. They are pitch, loudness, brightness, and roughness. Corresponding acoustic features chosen here are fundamental frequency (fo), sound pressure level (SPL), normalized spectral centroid (NSC), and approximate entropy (ApEn). In this study, thyroarytenoid (TA) and cricothyroid (CT) activations were varied computationally to study their relationship with these four specific acoustic features. Additionally, postural and material property variables such as vocal fold length (L) and fiber stress (σ) in the three vocal fold tissue layers were also calculated. A fiber-gel finite element model developed at National Center for Voice and Speech was used for this purpose. Muscle activation plots were generated to obtain the dependency of postural and acoustic features on TA and CT muscle activations. These relationships were compared against data obtained from previous in vivo human larynx studies and from canine laryngeal studies. General trends are that fo and SPL increase with CT activation, while NSC decreases when CT activation is raised above 20%. With TA activation, acoustic features have no uniform trends, except SPL increases uniformly with TA if there is a co-variation with CT activation. Trends for postural variables and material properties are also discussed in terms of activation levels.


Author(s):  
H. Lan ◽  
A. M. Al-Jumaily ◽  
A. Mirnajafi

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.


1997 ◽  
Vol 106 (7) ◽  
pp. 533-543 ◽  
Author(s):  
Steven M. Zeitels ◽  
Glenn W. Bunting ◽  
Robert E. Hillman ◽  
Traci Vaughn

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.


Author(s):  
Scott R. Moisik ◽  
John H. Esling

Purpose Physiological and phonetic studies suggest that, at moderate levels of epilaryngeal stricture, the ventricular folds impinge upon the vocal folds and influence their dynamical behavior, which is thought to be responsible for constricted laryngeal sounds. In this work, the authors examine this hypothesis through biomechanical modeling. Method The dynamical response of a low-dimensional, lumped-element model of the vocal folds under the influence of vocal–ventricular fold coupling was evaluated. The model was assessed for F0 and cover-mass phase difference. Case studies of simulations of different constricted phonation types and of glottal stop illustrate various additional aspects of model performance. Results Simulated vocal–ventricular fold coupling lowers F0 and perturbs the mucosal wave. It also appears to reinforce irregular patterns of oscillation, and it can enhance laryngeal closure in glottal stop production. Conclusion The effects of simulated vocal–ventricular fold coupling are consistent with sounds, such as creaky voice, harsh voice, and glottal stop, that have been observed to involve epilaryngeal stricture and apparent contact between the vocal folds and ventricular folds. This supports the view that vocal–ventricular fold coupling is important in the vibratory dynamics of such sounds and, furthermore, suggests that these sounds may intrinsically require epilaryngeal stricture.


Author(s):  
Byron D. Erath ◽  
Matías Zañartu ◽  
Sean D. Peterson ◽  
Michael W. Plesniak

Voiced speech is initiated as air is expelled from the lungs and passes through the vocal tract inciting self-sustained oscillations of the vocal folds. While various approaches exist for investigating both normal and pathological speech, the relative inaccessibility of the vocal folds make multi-mass speech models an attractive alternative. Their behavior has been benchmarked with excised larynx experiments, and they have been used as analysis tools for both normal and disordered speech, including investigations of paralysis, vocal tremor, and breathiness. However, during pathological speech, vocal fold motion is often unstructured, resulting in chaotic motion and a wealth of nonlinear phenomena. Unfortunately, current methodologies for multi-mass speech models are unable to replicate the nonlinear vocal fold behavior that often occurs in physiological diseased voice for realistic values of subglottal pressure.


Author(s):  
L. Hai ◽  
A. M. Al-Jumaily ◽  
A. Mirnajafi

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.


2016 ◽  
Vol 31 (3) ◽  
pp. 179-184 ◽  
Author(s):  
Ellen Graham ◽  
Vrushali Angadi ◽  
Joanna Sloggy ◽  
Joseph Stemple

Breathiness in the singing voice is problematic for classical singers. Voice students and singing teachers typically attribute breathiness to breath management issues and breathing technique. The present study sought to determine whether glottic insufficiency may also contribute to breathiness in a singer’s voice. Studies have revealed a relationship between insufficient vocal fold closure and inefficiency in the speaking voice. However, the effect of insufficient vocal fold closure on vocal efficiency in singers has yet to be determined. Two groups of voice students identified with and without breathiness issues underwent aerodynamic and acoustic voice assessment as well as laryngeal stroboscopy of the vocal folds to quantify the prevalence of insufficient vocal fold closure, also known as glottic insufficiency. These assessments revealed four groups: 1) those with glottic insufficiency and no perceived voice breathiness; 2) those with glottic sufficiency and perceived voice breathiness; 3) those with glottic insufficiency and perceived breathiness; and 4) those with glottic sufficiency and no perceived breathiness. Results suggest that previously undiscovered glottal insufficiency is common in young singers, particularly women, though the correlation with identified breathiness was not statistically significant. Acoustic and aerodynamic measures including noise-to-harmonics ratio, maximum phonation time, airflow rate, subglottal pressure, and laryngeal airway resistance were most sensitive to glottic insufficiency.


2006 ◽  
Vol 101 (4) ◽  
pp. 1104-1112 ◽  
Author(s):  
I-Jung Lu ◽  
Kun-Ze Lee ◽  
Ji-Chuu Hwang

Our recent studies show that intravenous administration of capsaicin induces enhancement of the intralaryngeal thyroarytenoid (TA) branch but a reduction of the intralaryngeal abducent branch, suggesting that the glottis is likely closed by capsaicin. The aim of the present study was to examine whether the glottis is adducted by intravenous administration of capsaicin. Electromyographic (EMG) activity of the TA muscle, subglottal pressure (SGP), and glottal behavior were evaluated before and after intravenous administration of capsaicin in male Wistar rats that were anesthetized and tracheostomized. Catheters were placed in the femoral artery and vein, as well as in the right jugular vein. Low and high doses of capsaicin (0.625 and 1.25 μg/kg) produced apnea and increases in the amplitude of the TA EMG. This enhancement of the TA EMG was observed during apnea as well as during recovery from apnea. Moreover, the onset of the TA EMG was advanced such that it commenced earlier during inspiration. Concomitantly, the SGP substantially increased. Increases in both the TA EMG and SGP were abolished after bilateral sectioning of the recurrent laryngeal nerve. In some animals, movement of the vocal folds was recorded by taking a motion picture with a digital camera under a surgical microscope. With intravenous administration of capsaicin, a tight glottal closure, decreases in blood pressure, and bradycardia were observed. These results strongly suggest that glottal closure is reflexively induced by intravenous administration of capsaicin and that closure of the glottis is beneficial for the defense of the airway and lungs when an animal is exposed to environmental irritants.


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