A Wave Reflection Analog Extension for Reduced Order Vocal Fold Investigations With Asymmetric Intraglottal Flows

2012 ◽  
Author(s):  
Byron D. Erath ◽  
Sean D. Peterson ◽  
Matias Zañartu ◽  
Michael W. Plesniak
Keyword(s):  
Vocal Fold ◽  
Vocal Tract ◽  
Coupling Effect ◽  
Vocal Folds ◽  
Tissue Properties ◽  
Sustained Oscillations ◽  
Voiced Speech ◽  
Vocal Fold Dynamics ◽  
Static Fluid ◽  
Speech Science

Voiced speech involves complex fluid-structure-acoustic interactions. When a critical lung pressure is achieved, the vocal folds are pushed apart inciting self-sustained oscillations. The interplay between the aerodynamic forces and the myoelastic tissue properties produces robust oscillation of the vocal folds. The pulsatile nature of the flow as it emanates from vocal folds creates an oscillatory pressure field which acoustically excites the vocal tract and ultimately forms intelligible sound. Recently, it has been shown that the acoustic pressures are high enough in magnitude that they modulate the static fluid pressures which drive the flow.1 This coupling effect creates a feedback loop with the fluids, acoustics, and vocal fold dynamics becoming interconnected. Consequently, speech science investigations that aim to capture the relevant physics must consider all three components to yield credible, clinically-relevant results.

Nonlinear Vocal Fold Dynamics in a Two-Mass Model of Speech Arising From Asymmetric Intraglottal Flow

2011 ◽  
Author(s):  
Byron D. Erath ◽  
Matías Zañartu ◽  
Sean D. Peterson ◽  
Michael W. Plesniak
Keyword(s):  
Vocal Fold ◽  
Vocal Tract ◽  
Vocal Folds ◽  
Attractive Alternative ◽  
Nonlinear Phenomena ◽  
Mass Model ◽  
Sustained Oscillations ◽  
Voiced Speech ◽  
Subglottal Pressure ◽  
Vocal Fold Dynamics

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.

Monitoring Vocal Fold Abduction through Vocal Fold Contact Area

1988 ◽  
Vol 31 (3) ◽  
pp. 338-351 ◽  
Author(s):  
Martin Rothenberg ◽  
James J. Mahshie
Keyword(s):  
Contact Area ◽  
Time Variation ◽  
Vocal Fold ◽  
Thyroid Cartilage ◽  
Electrical Conductance ◽  
Vocal Folds ◽  
Linear Phase ◽  
Voice Production ◽  
Voiced Speech ◽  
High Pass

A number of commercial devices for measuring the transverse electrical conductance of the thyroid cartilage produce waveforms that can be useful for monitoring movements within the larynx during voice production, especially movements that are closely related to the time-variation of the contact between the vocal folds as they vibrate. This paper compares the various approaches that can be used to apply such a device, usually referred to as an electroglottograph, to the problem of monitoring the time-variation of vocal fold abduction and adduction during voiced speech. One method, in which a measure of relative vocal fold abduction is derived from the duty cycle of the linear-phase high pass filtered electroglottograph waveform, is developed in detail.

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.

scholarly journals Vocal Fold Mass Is Not A Useful Quantity for Describing F 0 in Vocalization

2011 ◽  
Vol 54 (2) ◽  
pp. 520-522 ◽  
Keyword(s):  
Fundamental Frequency ◽  
Vocal Fold ◽  
Vocal Folds ◽  
Point Mass ◽  
Elastic Continuum ◽  
Animal Vocalization ◽  
Speech Science

Purpose Confusion exists about the effect of mass and size of the vocal folds on fundamental frequency (F 0 ) of phonation. In particular, greater vocal fold thickness is often assumed to be associated with lower F 0 . The purpose here is to show that such a relationship does not exist and that F 0 should be conceptualized with quantities other than mass (i.e., length and tissue stress). Method Arguments are made on the basis of fundamental laws of mechanics (point-mass vs. distributed mass). Conclusion In speech science, phonetics, and animal vocalization disciplines, instruction should shift away from point-mass descriptions of vocal fold tissue and toward an understanding of mode frequencies in an elastic continuum.

scholarly journals Estimating Vocal Fold Contact Pressure from Raw Laryngeal High-Speed Videoendoscopy Using a Hertz Contact Model

2019 ◽  
Vol 9 (11) ◽  
pp. 2384 ◽  
Author(s):  
Manuel E. Díaz-Cádiz ◽  
Sean D. Peterson ◽  
Gabriel E. Galindo ◽  
Víctor M. Espinoza ◽  
Mohsen Motie-Shirazi ◽  
...  
Keyword(s):  
Contact Pressure ◽  
Video Processing ◽  
Vocal Fold ◽  
High Speed ◽  
Numerical Models ◽  
Objective Assessment ◽  
Direct Methods ◽  
Vocal Folds ◽  
Processing Technique ◽  
Tissue Properties

The development of trauma-induced lesions of the vocal folds (VFs) has been linked to a high collision pressure on the VF surface. However, there are no direct methods for the clinical assessment of VF collision, thus limiting the objective assessment of these disorders. In this study, we develop a video processing technique to directly quantify the mechanical impact of the VFs using solely laryngeal kinematic data. The technique is based on an edge tracking framework that estimates the kinematic sequence of each VF edge with a Kalman filter approach and a Hertzian impact model to predict the contact force during the collision. The proposed formulation overcomes several limitations of prior efforts since it uses a more relevant VF contact geometry, it does not require calibrated physical dimensions, it is normalized by the tissue properties, and it applies a correction factor for using a superior view only. The proposed approach is validated against numerical models, silicone vocal fold models, and prior studies. A case study with high-speed videoendoscopy recordings provides initial insights between the sound pressure level and contact pressure. Thus, the proposed method has a high potential in clinical practice and could also be adapted to operate with laryngeal stroboscopic systems.

scholarly journals Apoptosis and Vocal Fold Disease: Clinically Relevant Implications of Epithelial Cell Death

2017 ◽  
Vol 60 (5) ◽  
pp. 1264-1272 ◽  
Author(s):  
Carolyn K. Novaleski ◽  
Bruce D. Carter ◽  
M. Preeti Sivasankar ◽  
Sheila H. Ridner ◽  
Mary S. Dietrich ◽  
...  
Keyword(s):  
Cell Death ◽  
Vocal Fold ◽  
Apoptotic Cell ◽  
Vocal Folds ◽  
Epithelial Tissue ◽  
Tissue Properties ◽  
Vocal Function ◽  
Detrimental Impact ◽  
Epithelial Cell Death

Purpose Vocal fold diseases affecting the epithelium have a detrimental impact on vocal function. This review article provides an overview of apoptosis, the most commonly studied type of programmed cell death. Because apoptosis can damage epithelial cells, this article examines the implications of apoptosis on diseases affecting the vocal fold cover. Method A review of the extant literature was performed. We summarized the topics of epithelial tissue properties and apoptotic cell death, described what is currently understood about apoptosis in the vocal fold, and proposed several possible explanations for how the role of abnormal apoptosis during wound healing may be involved in vocal pathology. Results and Conclusions Apoptosis plays an important role in maintaining normal epithelial tissue function. The biological mechanisms responsible for vocal fold diseases of epithelial origin are only beginning to emerge. This article discusses speculations to explain the potential role of deficient versus excessive rates of apoptosis and how disorganized apoptosis may contribute to the development of common diseases of the vocal folds.

Cost Effective Electrolarynx: A Feasibility Study

2013 ◽  
Author(s):  
Janine M. Amell ◽  
Robert W. Griffin ◽  
Madison B. Malfa ◽  
Christopher J. Nycz ◽  
Allen O. Osaheni ◽  
...  
Keyword(s):  
Vocal Fold ◽  
Vocal Tract ◽  
Pressure Oscillation ◽  
Cost Effective ◽  
The United States ◽  
Fluid Structure Interactions ◽  
Cancer Society ◽  
Periodic Pressure ◽  
Voiced Speech ◽  
The Individual

Speech is one of the most fundamental forms of self-expression and communication in humans [1]. Voiced speech is produced by fluid-structure interactions that drive vocal fold oscillations, creating a periodic pressure oscillation in the vocal tract. This excitation has a fundamental frequency, typically ranging between 100 and 200 Hz, depending on the individual. Thousands of people lose this ability each year when they are forced to undergo a total laryngectomy, which removes the entire larynx, usually to prevent the spread of cancer. The American Cancer Society predicts there will be about 3,000 laryngectomees in the United States alone during 2013 [2][3].

scholarly journals The Role of Finite Displacements in Vocal Fold Modeling

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Siyuan Chang ◽  
Fang-Bao Tian ◽  
Haoxiang Luo ◽  
James F. Doyle ◽  
Bernard Rousseau
Keyword(s):  
Geometric Nonlinearity ◽  
Vocal Fold ◽  
Computational Models ◽  
Vocal Folds ◽  
Small Displacement ◽  
Linear Elasticity Theory ◽  
Finite Displacements ◽  
Medial Surfaces ◽  
Vocal Fold Dynamics ◽  
The Impact

Human vocal folds experience flow-induced vibrations during phonation. In previous computational models, the vocal fold dynamics has been treated with linear elasticity theory in which both the strain and the displacement of the tissue are assumed to be infinitesimal (referred to as model I). The effect of the nonlinear strain, or geometric nonlinearity, caused by finite displacements is yet not clear. In this work, a two-dimensional model is used to study the effect of geometric nonlinearity (referred to as model II) on the vocal fold and the airflow. The result shows that even though the deformation is under 1 mm, i.e., less than 10% of the size of the vocal fold, the geometric nonlinear effect is still significant. Specifically, model I underpredicts the gap width, the flow rate, and the impact stress on the medial surfaces as compared to model II. The study further shows that the differences are caused by the contact mechanics and, more importantly, the fluid-structure interaction that magnifies the error from the small-displacement assumption. The results suggest that using the large-displacement formulation in a computational model would be more appropriate for accurate simulations of the vocal fold dynamics.

scholarly journals An Investigation of Vocal Tract Characteristics for Acoustic Discrimination of Pathological Voices

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Jung-Won Lee ◽  
Hong-Goo Kang ◽  
Jeung-Yoon Choi ◽  
Young-Ik Son
Keyword(s):  
Vocal Cord ◽  
Vocal Fold ◽  
Vocal Tract ◽  
Vocal Cord Paralysis ◽  
Vocal Folds ◽  
Normal Subjects ◽  
Additional Information ◽  
Acoustic Discrimination ◽  
Improved Performance ◽  
Unilateral Vocal Cord Paralysis

This paper investigates the effectiveness of measures related to vocal tract characteristics in classifying normal and pathological speech. Unlike conventional approaches that mainly focus on features related to the vocal source, vocal tract characteristics are examined to determine if interaction effects between vocal folds and the vocal tract can be used to detect pathological speech. Especially, this paper examines features related to formant frequencies to see if vocal tract characteristics are affected by the nature of the vocal fold-related pathology. To test this hypothesis, stationary fragments of vowel /aa/ produced by 223 normal subjects, 472 vocal fold polyp subjects, and 195 unilateral vocal cord paralysis subjects are analyzed. Based on the acoustic-articulatory relationships, phonation for pathological subjects is found to be associated with measures correlated with a raised tongue body or an advanced tongue root. Vocal tract-related features are also found to be statistically significant from the Kruskal-Wallis test in distinguishing normal and pathological speech. Classification results demonstrate that combining the formant measurements with vocal fold-related features results in improved performance in differentiating vocal pathologies including vocal polyps and unilateral vocal cord paralysis, which suggests that measures related to vocal tract characteristics may provide additional information in diagnosing vocal disorders.

High-Speed Imaging of Vocal Fold Vibrations and Larynx Movements within Vocalizations of Different Vowels

1996 ◽  
Vol 105 (12) ◽  
pp. 975-981 ◽  
Author(s):  
Dieter Maurer ◽  
Markus Hess ◽  
Manfred Gross
Keyword(s):  
Fundamental Frequency ◽  
Digital Imaging ◽  
Vocal Fold ◽  
High Speed ◽  
Vocal Tract ◽  
Vocal Folds ◽  
High Speed Imaging ◽  
Filter Model ◽  
Acoustic Interaction ◽  
Glottal Source

Theoretic investigations of the “source-filter” model have indicated a pronounced acoustic interaction of glottal source and vocal tract. Empirical investigations of formant pattern variations apart from changes in vowel identity have demonstrated a direct relationship between the fundamental frequency and the patterns. As a consequence of both findings, independence of phonation and articulation may be limited in the speech process. Within the present study, possible interdependence of phonation and phoneme was investigated: vocal fold vibrations and larynx position for vocalizations of different vowels in a healthy man and woman were examined by high-speed light-intensified digital imaging. We found 1) different movements of the vocal folds for vocalizations of different vowel identities within one speaker and at similar fundamental frequency, and 2) constant larynx position within vocalization of one vowel identity, but different positions for vocalizations of different vowel identities. A possible relationship between the vocal fold vibrations and the phoneme is discussed.

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