scholarly journals Effect of Subglottic Stenosis on Vocal Fold Vibration and Voice Production Using Fluid–Structure–Acoustics Interaction Simulation

2021 ◽  
Vol 11 (3) ◽  
pp. 1221
Author(s):  
Dariush Bodaghi ◽  
Qian Xue ◽  
Xudong Zheng ◽  
Scott Thomson
Keyword(s):  
Flow Rate ◽  
Vocal Fold ◽  
Flow Resistance ◽  
Signal To Noise Ratio ◽  
Area Ratio ◽  
Subglottic Stenosis ◽  
Fluid Structure ◽  
Voice Production ◽  
Vocal Fold Vibration ◽  
Glottal Flow

An in-house 3D fluid–structure–acoustic interaction numerical solver was employed to investigate the effect of subglottic stenosis (SGS) on dynamics of glottal flow, vocal fold vibration and acoustics during voice production. The investigation focused on two SGS properties, including severity defined as the percentage of area reduction and location. The results show that SGS affects voice production only when its severity is beyond a threshold, which is at 75% for the glottal flow rate and acoustics, and at 90% for the vocal fold vibrations. Beyond the threshold, the flow rate, vocal fold vibration amplitude and vocal efficiency decrease rapidly with SGS severity, while the skewness quotient, vibration frequency, signal-to-noise ratio and vocal intensity decrease slightly, and the open quotient increases slightly. Changing the location of SGS shows no effect on the dynamics. Further analysis reveals that the effect of SGS on the dynamics is primarily due to its effect on the flow resistance in the entire airway, which is found to be related to the area ratio of glottis to SGS. Below the SGS severity of 75%, which corresponds to an area ratio of glottis to SGS of 0.1, changing the SGS severity only causes very small changes in the area ratio; therefore, its effect on the flow resistance and dynamics is very small. Beyond the SGS severity of 75%, increasing the SGS severity, leads to rapid increases of the area ratio, resulting in rapid changes in the flow resistance and dynamics.

scholarly journals A Deep Neural Network Based Glottal Flow Model for Predicting Fluid-Structure Interactions during Voice Production

2020 ◽  
Vol 10 (2) ◽  
pp. 705
Author(s):  
Yang Zhang ◽  
Xudong Zheng ◽  
Qian Xue
Keyword(s):  
Neural Network ◽  
Flow Resistance ◽  
Deep Neural Network ◽  
Shape Function ◽  
Resistance Coefficient ◽  
Prediction Performance ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Voice Production ◽  
Glottal Flow

This paper proposes a machine-learning based reduced-order model that can provide fast and accurate prediction of the glottal flow during voice production. The model is based on the Bernoulli equation with a viscous loss term predicted by a deep neural network (DNN) model. The training data of the DNN model is a Navier-Stokes (N-S) equation-based three-dimensional simulation of glottal flows in various glottal shapes generated by a synthetic shape function, which can be obtained by superimposing the instantaneous modal displacements during vibration on the prephonatory geometry of the glottal shape. The input parameters of the DNN model are the geometric and flow parameters extracted from discretized cross sections of the glottal shapes and the output target is the corresponding flow resistance coefficient. With this trained DNN-Bernoulli model, the flow resistance coefficient as well as the flow rate and pressure distribution in any given glottal shape generated by the synthetic shape function can be predicted. The model is further coupled with a finite-element method based solid dynamics solver for simulating fluid-structure interactions (FSI). The prediction performance of the model for both static shape and FSI simulations is evaluated by comparing the solutions to those obtained by the Bernoulli and N-S model. The model shows a good prediction performance in accuracy and efficiency, suggesting a promise for future clinical use.

Effect of Supraglottal Acoustics On Fluid-Structure Interaction During Human Voice Production

2021 ◽  
Author(s):  
Dariush Bodaghi ◽  
Weili Jiang ◽  
Qian Xue ◽  
Xudong Zheng
Keyword(s):  
Flow Rate ◽  
Vocal Fold ◽  
Splitting Method ◽  
Acoustic Resonance ◽  
Coupled Processes ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Voice Production ◽  
Acoustic Perturbation ◽  
Human Voice

Abstract A hydrodynamic/acoustic splitting method was used to examine the effect of supraglottal acoustics on fluid-structure interactions during human voice production in a two-dimensional computational model. The accuracy of the method in simulating compressible flows in typical human airway conditions was verified by comparing it to full compressible flow simulations. The method was coupled with a three-mass model of vocal fold lateral motion to simulate fluid-structure interactions during human voice production. By separating the acoustic perturbation components of the airflow, the method allows isolation of the role of supraglottal acoustics in fluid-structure interactions. The results showed that an acoustic resonance between a higher harmonic of the sound source and the first formant of the supraglottal tract occurred during normal human phonation when the fundamental frequency was much lower than the formants. The resonance resulted in acoustic pressure perturbation at the glottis which was of the same order as the incompressible flow pressure and found to affect vocal fold vibrations and glottal flow rate waveform. Specifically, the acoustic perturbation delayed the opening of the glottis, reduced the vertical phase difference of vocal fold vibrations, decreased flow rate and maximum flow deceleration rate at the glottal exit; yet, they had little effect on glottal opening. The results imply that the sound generation in the glottis and acoustic resonance in the supraglottal tract are coupled processes during human voice production and computer modeling of vocal fold vibrations needs to include supraglottal acoustics for accurate predictions.

Design of Apparatus for Studying Aerodynamics of Voice Production

2004 ◽  
Author(s):  
Michael Barry
Keyword(s):  
Flow Visualization ◽  
Vocal Fold ◽  
Sound Production ◽  
Vocal Tract ◽  
Vocal Folds ◽  
Flow Speed ◽  
Working Fluid ◽  
Voice Production ◽  
Experimental Apparatus ◽  
Glottal Flow

The design and testing of an experimental apparatus for in vitro study of phonatory aerodynamics (voice production) in humans is presented. The presentation includes not only the details of apparatus design, but flow visualization and Digital Particle Image Velocimetry (DPIV) measurements of the developing flow that occurs during the opening of the constriction from complete closure. The main features of the phonation process have long been understood. A proper combination of air flow from the lungs and of vocal fold tension initiates a vibration of the vocal folds, which in turn valves the airflow. The resulting periodic acceleration of the airstream through the glottis excites the acoustic modes of the vocal tract. It is further understood that the pressure gradient driving glottal flow is related to flow separation on the downstream side of the vocal folds. However, the details of this process and how it may contribute to effects such as aperiodicity of the voice and energy losses in voiced sound production are still not fully grasped. The experimental apparatus described in this paper is designed to address these issues. The apparatus itself consists of a scaled-up duct in which water flows through a constriction whose width is modulated by motion of the duct wall in a manner mimicking vocal fold vibration. Scaling the duct up 10 times and using water as the working fluid allows temporally and spatially resolved measurements of the dynamically similar flow velocity field using DPIV at video standard framing rates (15Hz). Dynamic similarity is ensured by matching the Reynolds number (based on glottal flow speed and glottis width) of 8000, and by varying the Strouhal number (based on vocal fold length, glottal flow speed, and a time scale characterizing the motion of the vocal folds) ranging from 0.01 to 0.1. The walls of the 28 cm × 28 cm test section and the vocal fold pieces are made of clear cast acrylic to allow optical access. The vocal fold pieces are 12.7 cm × 14 cm × 28 cm and are rectangular in shape, except for the surfaces which form the glottis, which are 6.35 cm radius half-circles. Dye injection slots are placed on the upstream side of both vocal field pieces to allow flow visualization. Prescribed motion of the vocal folds is provided by two linear stages. Linear bearings ensure smooth execution of the motion prescribed using a computer interface. Measurements described here use the Laser-Induced Fluorescence (LIF) flow visualization and DPIV techniques and are performed for two Strouhal numbers to assess the effect of opening time on the development of the glottal jet. These measurements are conducted on a plane oriented perpendicular to the glottis, at the duct midplane. LIF measurements use a 5W Argon ion laser to produce a light sheet, which illuminates the dye injected through a slot in each vocal fold piece. Two dye colors are used, one for each side. Quantitative information about the velocity and vorticity fields are obtained through DPIV measurements at the same location as the LIF measurements.

Variations Across Time in Acoustic and Electroglottographic Measures of Phonatory Function in Women With and Without Vocal Nodules

1995 ◽  
Vol 38 (4) ◽  
pp. 783-793 ◽  
Author(s):  
Kelly Dailey Hall
Keyword(s):  
Duty Cycle ◽  
Vocal Fold ◽  
Signal To Noise Ratio ◽  
Control Group ◽  
Signal To Noise ◽  
Vocal Fold Vibration ◽  
Audio Recordings ◽  
Vocal Nodules ◽  
Experimental Group ◽  
Over Time

The purpose of this investigation was to identify variations over time in phonatory function of women with and without vocal nodules using acoustic and electroglottographic measures. Subjects were 10 women with vocal nodules (mean age=22.1, range=19–25) and 10 women with healthy larynges (mean age=25.0, range=18–32). Electroglottographic and audio recordings of speech were obtained for each subject over 3 consecutive days at three target times: morning, afternoon, and evening. Estimates of fundamental frequency (Hz), jitter (msec), shimmer (dB), and signal-to-noise ratio (dB) were made from a 1000 msec midportion of the vowel /α/ produced in a carrier phrase. In addition, a closed-to-open ratio was derived from the EGG duty cycle of the same 1000 msec segment and used to estimate timing characteristics of vocal fold vibration. The results showed no significant differences between the groups regarding a pattern of change in the acoustic or the EGG measures across times throughout the day. Furthermore, the experimental group demonstrated significantly lower closed-to-open ratios than the control group. With this exception, no other statistically significant differences between the groups were found.

Using Semi-Occluded Vocal Tract Exercises in Voice Therapy: The Clinician's Primer

2014 ◽  
Vol 24 (2) ◽  
pp. 71-79 ◽  
Author(s):  
Marci D. Rosenberg
Keyword(s):  
Vocal Fold ◽  
Vocal Tract ◽  
Voice Therapy ◽  
Exact Nature ◽  
Voice Production ◽  
Vocal Fold Vibration

Semi-occluded vocal tract (SOVT) exercises have long been used by voice trainers and pedagogues and have been particularly popular in Scandinavia dating as far back as the 1800s. Titze (1988, 1994, 2006; Titze, Riede, & Popolo, 2008; Titze & Verdolini-Abbot, 2012) has contributed significantly to the exploration of the SOVT and impact on voice production, and these types of exercise have become ubiquitous in the clinical voice arena. Although SOVT exercises are commonly used, there continue to be questions about the exact nature of how they impact phonation and improved vocal economy. This article aims to explore the physiology of a SOVT on vocal fold vibration and vocal output. Several variations are described within context of recent research.

Computational Modeling of Voice Production Using Excised Canine Larynx

2021 ◽  
Author(s):  
Weili Jiang ◽  
Charles Farbos De Luzan ◽  
Xiaojian Wang ◽  
Liran Oren ◽  
Sid Khosla ◽  
...  
Keyword(s):  
Vocal Fold ◽  
Stokes Equations ◽  
Element Model ◽  
Numerical Work ◽  
Continuous Increase ◽  
Voice Production ◽  
Flow Recirculation ◽  
Flow Swirl ◽  
Glottal Flow ◽  
Divergent Angle

Abstract A combined experimental-numerical work was conducted to comprehensively validate a subject-specific continuum model of voice production in larynx using excised canine laryngeal experiments. The computational model is a coupling of the Navier-Stokes equations for glottal flow dynamics and a finite element model of vocal fold dynamics. The numerical simulations employed a cover-body vocal fold structure with the geometry reconstructed from MRI scans and the material properties determined through an optimization-based inverse process of experimental indentation measurement. The results showed that the simulations predicted key features of the dynamics observed in the experiments, including the skewing of the glottal flow waveform, mucosal wave propagation, continuous increase of the divergent angle and intraglottal swirl strength during glottal closing, and flow recirculation between glottal jet and vocal fold. The simulations also predicted the increase of the divergent angle, glottal jet speed and intraglottal flow swirl strength with the subglottal pressure, same as in the experiments. Quantitatively, the simulations over-predicted the frequency and jet speed and under-predicted the flow rate and divergent angle for the larynx under study. The limitations of the model and their implications were discussed.

Biomechanical Effects of Hydration in Vocal Fold Tissues

2002 ◽  
Vol 126 (5) ◽  
pp. 528-537 ◽  
Author(s):  
Roger W. Chan ◽  
Niro Tayama
Keyword(s):  
Shear Modulus ◽  
Viscoelastic Properties ◽  
Vocal Fold ◽  
Damping Ratio ◽  
Empirical Support ◽  
Tissue Stiffness ◽  
Voice Production ◽  
Vocal Fold Vibration ◽  
Elastic Shear

OBJECTIVE: It has often been hypothesized, with little empirical support, that vocal fold hydration affects voice production by mediating changes in vocal fold tissue rheology. To test this hypothesis, we attempted in this study to quantify the effects of hydration on the viscoelastic shear properties of vocal fold tissues in vitro. STUDY DESIGN: Osmotic changes in hydration (dehydration and rehydration) of 5 excised canine larynges were induced by sequential incubation of the tissues in isotonic, hypertonic, and hypotonic solutions. Elastic shear modulus ( G'), dynamic viscosity η' and the damping ratio ζ of the vocal fold mucosa (lamina propria) were measured as a function of frequency (0.01 to 15 Hz) with a torsional rheometer. RESULTS: Vocal fold tissue stiffness (G') and viscosity increased significantly (by 4 to 7 times) with the osmotically induced dehydration, whereas they decreased by 22% to 38% on the induced rehydration. Damping ratio (ζ) also increased with dehydration and decreased with rehydration, but the detected differences were not statistically significant at all frequencies. CONCLUSION: These findings support the longstanding hypothesis that hydration affects vocal fold vibration by altering tissue rheologic (or viscoelastic) properties. SIGNIFICANCE: Our results demonstrated the biomechanical importance of hydration in vocal fold tissues and suggested that hydration approaches may potentially improve the biomechanics of phonation in vocal fold lesions involving disordered fluid balance.

What can vortices tell us about vocal fold vibration and voice production

2008 ◽  
Vol 16 (3) ◽  
pp. 183-187 ◽  
Author(s):  
Sid Khosla ◽  
Shanmugam Murugappan ◽  
Ephraim Gutmark
Keyword(s):  
Vocal Fold ◽  
Voice Production ◽  
Vocal Fold Vibration
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