Unilateral Vocal Fold Paralysis: Does the Paralyzed Vocal Fold Oscillate Slower or Faster Than the Healthy One?

Objective/hypothesis: This study aims to analyze the oscillatory behavior of healthy and paralyzed vocal folds in patients with unilateral vocal fold paralysis (UVFP) using laryngeal high-speed videoendoscopy (HSV). We analyzed the left-right oscillatory differences to test the hypotheses that the effective tension of the paralyzed vocal fold is: (h) lower, (h) higher, or (h) similar, when compared with the healthy vocal fold.

Methods: Digital kymograms were obtained from sustained phonations of 20 patients (10 females, 10 males) with UVFP.

Application of nonlinear dynamics theory to understanding normal and pathologic voices in humans.

The theory of nonlinear dynamics was introduced to voice science in the 1990s and revolutionized our understanding of human voice production mechanisms. This theory elegantly explains highly complex phenomena in the human voice, such as subharmonic and rough-sounding voice, register breaks, and intermittent aphonic breaks. These phenomena occur not only in pathologic, dysphonic voices but are also explored for artistic purposes, such as contemporary singing.

Vocal Fold Kinematics and Convergent-Divergent Oscillatory Glottis: Basic Insights Using Mucosal Wave Modeling and Synthetic Kymograms.

Purpose: Owing to mucosal waves, the oscillatory glottis is ideally expected to be convergent during opening and divergent during closing. However, this does not necessarily hold for voice disorders. Here, we pave the way for recognizing COnvergent-DIvergent (CODI) waveforms quantitatively and study the kinematic conditions in which they occur.

Determining the Mouth-to-Microphone Distance in Rigid Laryngoscopy: A Simple Solution Based on the Newly Measured Values of the Depth of Endoscope Insertion into the Mouth.

Mouth-to-microphone (MTM) distance is important when measuring the sound of voice. However, determining the MTM distance for laryngoscope-mounted microphones during laryngoscopic examinations is cumbersome. We introduce a novel solution for such cases, using the depth of insertion of the laryngoscope into the mouth as a reference distance.

Domestic cat larynges can produce purring frequencies without neural input.

Most mammals produce vocal sounds according to the myoelastic-aerodynamic (MEAD) principle, through self-sustaining oscillation of laryngeal tissues. In contrast, cats have long been believed to produce their low-frequency purr vocalizations through a radically different mechanism involving active muscle contractions (AMC), where neurally driven electromyographic burst patterns (typically at 20-30 Hz) cause the intrinsic laryngeal muscles to actively modulate the respiratory airflow. Direct empirical evidence for this AMC mechanism is sparse.

Validation of the Czech Version of the Voice Handicap Index.

Objective(s): The present study aims to evaluate the reliability and construct validity of the Czech version of the Voice Handicap Index (VHI-CZ) and determine the cut-off value to distinguish dysphonic patients from nondysphonic individuals.

Study Design: Prospective study, Parallel group design.

Methods: The study investigated 100 adult patients with dysphonia, divided into three groups based on the etiology of the voice problem (neurogenic, functional, and structural).

Dynamic System Coupling in Voice Production.

Voice is a major means of communication for humans, non-human mammals and many other vertebrates like birds and anurans. The physical and physiological principles of voice production are described by two theories: the MyoElastic-AeroDynamic (MEAD) theory and the Source-Filter Theory (SFT). While MEAD employs a multiphysics approach to understand the motor control and dynamics of self-sustained vibration of vocal folds or analogous tissues, SFT predominantly uses acoustics to understand spectral changes of the source via linear propagation through the vocal tract.

Simulated Laryngeal High-Speed Videos for the Study of Normal and Dysphonic Vocal Fold Vibration.

Purpose: Laryngeal high-speed videoendoscopy (LHSV) has been recognized as a highly valuable modality for the scientific investigations of vocal fold (VF) vibrations. In contrast to stroboscopic imaging, LHSV enables visualizing aperiodic VF vibrations. However, the technique is less well established in the clinical care of disordered voices, partly because the properties of aperiodic vibration patterns are not yet described comprehensively.

Laryngeal and Acoustic Analysis of Chest and Head Registers Extended Across a Three-Octave Range: A Case Study.

Voice registers are assumed to be related to different laryngeal adjustments, but objective evidence has been insufficient. While chest register is usually associated with the lower pitch range, and head register with the higher pitch range, here we investigated a professional singer who claimed an ability to produce both these registers at every pitch, throughout her entire singing range. The singer performed separated phonations alternating between the two registers (further called chest-like and head-like) at all pitches from C3 (131 Hz) to C6 (1047 Hz).

Integrative Insights into the Myoelastic-Aerodynamic Theory and Acoustics of Phonation. Scientific Tribute to Donald G. Miller.

In this tribute article to D.G. Miller, we review some historical and recent contributions to understanding the myoelastic-aerodynamic (MEAD) theory of phonation and the related acoustic phenomena in subglottal and vocal tract.

Subglottal pressure oscillations in anechoic and resonant conditions and their influence on excised larynx phonations.

Excised larynges serve as natural models for studying behavior of the voice source. Acoustic resonances inside the air-supplying tubes below the larynx (i.e.

Influence of nasal cavities on voice quality: Computer simulations and experiments.

Nasal cavities are known to introduce antiresonances (dips) in the sound spectrum reducing the acoustic power of the voice. In this study, a three-dimensional (3D) finite element (FE) model of the vocal tract (VT) of one female subject was created for vowels [a:] and [i:] without and with a detailed model of nasal cavities based on CT (Computer Tomography) images. The 3D FE models were then used for analyzing the resonances, antiresonances and the acoustic pressure response spectra of the VT.

New red-emitting Schiff base chelates: promising dyes for sensing and imaging of temperature and oxygen phosphorescence decay time.

New complexes of Zn(ii), Pd(ii) and Pt(ii) with Schiff bases are prepared in a one-step condensation of 4-(dibutylamino)-2-hydroxybenzaldehyde and 4,5-diaminophthalonitrile in the presence of a metal salt. The complexes possess efficient absorption in the blue-green part of the spectrum with molar absorption coefficients up to 98 000 M cm. The Pt(ii) complex shows very strong red phosphorescence in anoxic solutions at room temperature with a quantum yield of 65% in toluene which places it among the brightest emitters available for this spectral range.

Cepstral and Perceptual Investigations in Female Teachers With Functionally Healthy Voice.

Purpose: The present study aimed at measuring the smoothed and non-smoothed cepstral peak prominence (CPPS and CPP) in teachers who considered themselves to have normal voice but some of them had laryngeal pathology. The changes of CPP, CPPS, sound pressure level (SPL) and perceptual ratings with different voice tasks were investigated and the influence of vocal pathology on these measures was studied.

Method: Eighty-four Finnish female primary school teachers volunteered as participants.

Visual and Automatic Evaluation of Vocal Fold Mucosal Waves Through Sharpness of Lateral Peaks in High-Speed Videokymographic Images.

Introduction: The sharpness of lateral peaks is a visually helpful clinical feature in high-speed videokymographic (VKG) images indicating vertical phase differences and mucosal waves on the vibrating vocal folds and giving insights into the health and pliability of vocal fold mucosa. This study aims at investigating parameters that can be helpful in objectively quantifying the lateral peak sharpness from the VKG images.

Method: Forty-five clinical VKG images with different degrees of sharpness of lateral peaks were independently evaluated visually by three raters.

A Simple Method to Obtain Basic Acoustic Measures From Video Recordings as Subtitles.

Purpose: Sound pressure level (SPL) and fundamental frequency (fo) are very basic and important measures in the acoustical assessment of voice quality, and their variation influences also the vocal fold vibration characteristics. Most sophisticated laryngeal videostroboscopic systems therefore also measure and display the SPL and fo values directly over the video frames by means of a rather expensive special hardware setup. An alternative simple software-based method is presented here to obtain these measures as video subtitles.

Recommended Protocols for Instrumental Assessment of Voice: American Speech-Language-Hearing Association Expert Panel to Develop a Protocol for Instrumental Assessment of Vocal Function.

Purpose: The aim of this study was to recommend protocols for instrumental assessment of voice production in the areas of laryngeal endoscopic imaging, acoustic analyses, and aerodynamic procedures, which will (a) improve the evidence for voice assessment measures, (b) enable valid comparisons of assessment results within and across clients and facilities, and (c) facilitate the evaluation of treatment efficacy.

Method: Existing evidence was combined with expert consensus in areas with a lack of evidence. In addition, a survey of clinicians and a peer review of an initial version of the protocol via VoiceServe and the American Speech-Language-Hearing Association's Special Interest Group 3 (Voice and Voice Disorders) Community were used to create the recommendations for the final protocols.

Influence of Noise Resulting From the Location and Conditions of Classrooms and Schools in Upper Egypt on Teachers' Voices.

Purpose: Teachers are professional voice users, always at high risk of developing voice disorders due to high vocal demand and unfavorable environmental conditions. This study aimed at identifying possible correlations between teachers' voice symptoms and their perception of noise, the location of schools, as well as the location and conditions of their classrooms.

Method: One hundred forty teachers (ages 21-56) from schools in Upper Egypt participated in this study.

Tutorial and Guidelines on Measurement of Sound Pressure Level in Voice and Speech.

Purpose: Sound pressure level (SPL) measurement of voice and speech is often considered a trivial matter, but the measured levels are often reported incorrectly or incompletely, making them difficult to compare among various studies. This article aims at explaining the fundamental principles behind these measurements and providing guidelines to improve their accuracy and reproducibility.

Method: Basic information is put together from standards, technical, voice and speech literature, and practical experience of the authors and is explained for nontechnical readers.

Hemi-laryngeal Setup for Studying Vocal Fold Vibration in Three Dimensions.

The voice of humans and most non-human mammals is generated in the larynx through self-sustaining oscillation of the vocal folds. Direct visual documentation of vocal fold vibration is challenging, particularly in non-human mammals. As an alternative, excised larynx experiments provide the opportunity to investigate vocal fold vibration under controlled physiological and physical conditions.

Evaluation of clinical value of videokymography for diagnosis and treatment of voice disorders.

This study aimed at determining the clinical value of videokymography (VKG) as an additional tool for the assessment of voice disorders. 105 subjects with voice disorders were examined by an experienced laryngologist. A questionnaire was used to specify diagnosis, diagnostic confidence, and treatment recommendations before and after VKG.

Resonance Tube Phonation in Water-the Effect of Tube Diameter and Water Depth on Back Pressure and Bubble Characteristics at Different Airflows.

Objectives: Resonance tube phonation with tube end in water is a voice therapy method in which the patient phonates through a glass tube, keeping the free end of the tube submerged in water, creating bubbles. The purpose of this experimental study was to determine flow-pressure relationship, flow thresholds between bubble types, and bubble frequency as a function of flow and back volume.

Methods: A flow-driven vocal tract simulator was used for recording the back pressure produced by resonance tubes with inner diameters of 8 and 9 mm submerged at water depths of 0-7 cm.

Comparing Chalk With Cheese-The EGG Contact Quotient Is Only a Limited Surrogate of the Closed Quotient.

The electroglottographic (EGG) contact quotient (CQegg), an estimate of the relative duration of vocal fold contact per vibratory cycle, is the most commonly used quantitative analysis parameter in EGG. The purpose of this study is to quantify the CQegg's relation to the closed quotient, a measure more directly related to glottal width changes during vocal fold vibration and the respective sound generation events. Thirteen singers (six females) phonated in four extreme phonation types while independently varying the degree of breathiness and vocal register.

Phasegram Analysis of Vocal Fold Vibration Documented With Laryngeal High-speed Video Endoscopy.

Introduction: In a recent publication, the phasegram, a bifurcation diagram over time, has been introduced as an intuitive visualization tool for assessing the vibratory states of oscillating systems. Here, this nonlinear dynamics approach is augmented with quantitative analysis parameters, and it is applied to clinical laryngeal high-speed video (HSV) endoscopic recordings of healthy and pathological phonations.

Methods: HSV data from a total of 73 females diagnosed as healthy (n = 42), or with functional dysphonia (n = 15) or with unilateral vocal fold paralysis (n = 16), were quantitatively analyzed.