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A New Hypothesis for Fluidification of Vocal-Fold Mucus: Scintigraphic Study

Conclusion
The results indicate that an increased volume of saliva enters the larynx and is adsorbed in its mucosa, producing mucus fluidification. This supports our alternative hypothesis to the unlikely concept that hydration by water ingestion is the factor responsible for reduction of the mucus viscosity of the vocal folds.

from the Journal of Voice

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Measures of Vocal Attack Time for Healthy Young Adults

Conclusions
Normative data are presented for a new measure of the duration of vocal initiation, VAT. Acquiring this measure requires very little intervention by the user and, thereby, eliminates the influence of subjective decision making. Although beyond the scope of this article, we suggest several factors that might underlie VAT as a function of speaker sex and age.

from the Journal of Voice

Vocal pitch discrimination in the motor system

Speech production can be broadly separated into two distinct components: Phonation and Articulation. These two aspects require the efficient control of several phono-articulatory effectors. Speech is indeed generated by the vibration of the vocal-folds in the larynx (F0) followed by ‘‘filtering” by articulators, to select certain resonant frequencies out of that wave (F1, F2, F3, etc.). Recently it has been demonstrated that the motor representation of articulators (lips and tongue) participates in the discrimination of articulatory sounds (lips- and tongue-related speech sounds). Here we investigate whether the results obtained on articulatory sounds discrimination could be extended to phonation by applying a dual-pulse TMS protocol while subjects had to discriminate F0-shifted vocal utterances [a]. Stimulation over the larynx motor representation, compared to the control site (tongue/lips motor cortex), induced a reduction in RT for stimuli including a subtle pitch shift. We demonstrate that vocal pitch discrimination, in analogy with the articulatory component, requires the contribution of the motor system and that this effect is somatotopically organized.

from Brain and Language

The professional voice

The human voice is not only the key to human communication but also serves as the primary musical instrument. Many professions rely on the voice, but the most noticeable and visible are singers. Care of the performing voice requires a thorough understanding of the interaction between the anatomy and physiology of voice production, along with an awareness of the interrelationships between vocalisation, acoustic science and non-vocal components of performance. This review gives an overview of the care and prevention of professional voice disorders by describing the unique and integrated anatomy and physiology of singing, the roles of development and training, and the importance of the voice care team.

from the Journal of Laryngology and Otology

Maximum phonation time of vowels in adult women with vocal nodules*

for the group of adult women with vocal nodules, the MPT values were reduced and positively correlated; the MPT of vowel /a/ presented a lower value when compared to the other investigated vowels.

from Pró-Fono Revista de Atualização Científica

Effects of exposure to sulfur mustard on speech aerodynamics

Sulfur Mustard is an alkylating agent with highly cytotoxic properties even at low exposure. It was used widely against both military and civilian population by Iraqi forces in the Iraq-Iran war (1983-88). Although various aspects of mustard gas effects on patients with chemical injury have been relatively well characterized, its effects on speech are still evolving. We evaluated aerodynamics of speech in male patients following sulfur mustard inhalation. In a case-control study patients with chemical injuries (n = 19) along with age and sex-matched healthy control group (n = 20) were selected. Aerodynamic analyses were performed by using the Glasgow Airflow Measurement System (known as ST1 dysphonia). Results indicated that except mean flow rate, there were statistically significant differences in vital capacity, phonation time, phonation volume, vocal velocity index, total expired volume and phonation quotient of patients between experimental and control groups (P < 0.05). This study demonstrated mustard gas can impair different parameters of speech aerodynamics.

from the Journal of Communication Disorders

Objective Voice Analysis of Boys With Profound Hearing Loss

Conclusions
The results of the present study suggest that profoundly deaf children present with greater phonatory instability and spectral noise, with the possible inference of reduced laryngeal control relative to vocal quality. The finding of higher F0 for the boys with profound hearing loss suggests that they use a different control strategy for pitch, an area needing further study. These findings of acoustic and F0 differences of the hearing-impaired boys should be kept in mind for intervention practices especially when the social impact of deafness is considered.

from the Journal of Voice

Variations in Intensity, Fundamental Frequency, and Voicing for Teachers in Occupational Versus Nonoccupational Settings

Conclusions: Data regarding voicing percentages, F0, and dB SPL provide critical insight into teachers’ vocal health. Further, because nonoccupational voice use is added to an already overloaded voice, it may add key insights into recovery patterns and should be the focus of future studies.

from the Journal of Speech, Language, and Hearing Research

Considerations regarding vocal and laryngeal modifications caused by vocal fry in women without voice complaints

The aim of this study was to verify vocal and laryngeal modifications caused by vocal fry in five female subjects without vocal or laryngeal complaints. For this purpose, the sustained emission of the vowel /a/ was digitally recorded, as well as the recording of a videostroboscopic examination of the larynx. Subsequently, the subjects performed the vocal fry in three series of 15 repetitions, with a 30-second interval of passive rest between series, and carried out a second evaluation (recording of the sustained emission of the vowel /a/ and the videostroboscopic examination of the larynx). Both laryngeal and vocal data found prior to and after the vocal fry technique were submitted to acoustic, auditory-perceptive, and videostroboscopic analyses. The acoustic analysis was generated by the Multi Speech program. Analyses showed the following effects of the vocal fry: increase of the vibration of the vocal folds mucosa; alteration or maintenance of voice type and pitch; decrease or maintenance of measures related to jitter and shimmer, as well as the index that suggests glottic noise; decrease of the soft phonation index; maintenance or alteration of the vocal quality and resonance focus, with laryngopharyngeal prevalence; decrease of the fundamental frequency; and increase of frequency and width variations. The study allowed the conclusion that vocal fry had a positive effect on the vibration of the vocal folds mucosa as well as on voice noise, and a negative effect on voice resonance and stability.

from Revista de Sociedade Brasileira de Fonoaudiologia

Short-duration accelerated breathing challenges affect phonation

During daily activities, such as exercise, individuals may engage in accelerated breathing for prolonged durations. This study demonstrates that even extremely short durations of accelerated breathing may affect phonation.

from The Laryngoscope

Biomechanics of fundamental frequency regulation: Constitutive modeling of the vocal fold lamina propria

Accurate characterization of biomechanical characteristics of the vocal fold is critical for understanding the regulation of vocal fundamental frequency (F 0), which depends on the active control of the intrinsic laryngeal muscles as well as the passive biomechanical response of the vocal fold lamina propria. Specifically, the tissue stress-strain response and viscoelastic properties under cyclic tensile deformation are relevant, when the vocal folds are subjected to length and tension changes due to posturing. This paper describes a constitutive modeling approach quantifying the relationship between vocal fold stress and strain (or stretch), and establishes predictions of F 0 with the string model of phonation based on the constitutive parameters. Results indicated that transient and time-dependent changes in F 0, including global declinations in declarative sentences, as well as local F 0 overshoots and undershoots, can be partially attributed to the time-dependent viscoplastic response of the vocal fold cover.

from Logopedics Phoniatrics Vocology

Biomechanics of fundamental frequency regulation: Constitutive modeling of the vocal fold lamina propria

Accurate characterization of biomechanical characteristics of the vocal fold is critical for understanding the regulation of vocal fundamental frequency (F 0), which depends on the active control of the intrinsic laryngeal muscles as well as the passive biomechanical response of the vocal fold lamina propria. Specifically, the tissue stress-strain response and viscoelastic properties under cyclic tensile deformation are relevant, when the vocal folds are subjected to length and tension changes due to posturing. This paper describes a constitutive modeling approach quantifying the relationship between vocal fold stress and strain (or stretch), and establishes predictions of F 0 with the string model of phonation based on the constitutive parameters. Results indicated that transient and time-dependent changes in F 0, including global declinations in declarative sentences, as well as local F 0 overshoots and undershoots, can be partially attributed to the time-dependent viscoplastic response of the vocal fold cover.

from Logopedics Phoniatrics Vocology

Acoustic vocal modifications produced by reverse phonation

CONCLUSION: Reverse phonation promoted a positive effect over the vibration of the mucosa of the vocal folds and over their stretching. This result suggests an effect over the vocal muscles, favoring changes of fundamental frequency; and over the homogenization and modification of mucus layer. Moreover, it promoted a global improvement of the vocal signal and of the sensations during its production.

from Revista de Sociedade Brasileira de Fonoaudiologia

Study of the acoustic measures’ constancy of sustained vowels consecutive phonations in women without vocal complaint and women with dysphonia

CONCLUSIONS: Acoustic measures of different consecutive phonations of the same sustained vowel are constant, except for fundamental frequency, which can increase during the first phonations of individuals without vocal complaint and subjects with dysphonia and vocal nodules.

from Revista de Sociedade Brasileira de Fonoaudiologia

Role of vortices in voice production: Normal versus asymmetric tension

Objectives:
Decreasing the closing speed of the vocal folds can reduce loudness and energy in the higher frequency harmonics, resulting in reduced voice quality. Our aim was to study the correlation between higher frequencies and the intraglottal vorticity (which contributes to rapid closing by producing transient negative intraglottal pressures).

Methods:
Using six excised canine larynges (three with symmetric and three with asymmetric, periodic vocal fold motion), intraglottal vorticity was calculated from 2D velocity fields measured using particle imaging velocimetry.

Results:
There is a strong correlation between intraglottal vorticity and acoustic energy in the higher frequencies; in periodic asymmetric motion, the vorticity and higher frequencies are both reduced.

Conclusions:
For unilateral vocal fold paralysis, these findings suggest one reason why periodic, asymmetric motion, may produce an abnormal voice. Further study will help determine when and why reinnervation, as opposed to medialization, may result in better voice quality. Laryngoscope, 119:216-221, 2009

from Laryngoscope