Blog Archives

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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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

Vocal and laryngeal analyses in diagnostic hypotheses of nodules and cysts

CONCLUSION: Inspiratory phonation revealed differential characteristics for nodules and cysts diagnoses; the auditory-perceptual evaluation added information to characterize both lesions.

from Revista de Sociedade Brasileira de Fonoaudiologia

Air Pulse Deformation Measurement: A Preliminary Method for Noninvasive Vocal Fold Pliability Analysis

Conclusion: The results show that the technique allows automatic, quantitative, noninvasive vocal fold pliability measurements on awake subjects.

from Folia Phoniatrica et Logopaedica

Epithelial differentiation of adipose-derived stem cells for laryngeal tissue engineering

Conclusions:
A three-dimensional structure of fibrin and adipose-derived stem cells was created as a prototype vocal fold replacement. Two segregated cell phenotypes occurred, producing a bilayered structure resembling epithelium over lamina propria. This preliminary work demonstrates the feasibility of tissue engineering to produce structures for vocal fold replacement. Laryngoscope, 2009

from The Laryngoscope

First Case of a Myxofibrosarcoma of the Vocal Folds: Case Report and Review of the Literature

Summary
We present the first case of an endolaryngeal manifestation of a myxofibrosarcoma. These tumors represent a distinct clinicopathologic entity and are fibroblast-derived soft-tissue neoplasms usually arising in late adulthood. The tumor presented as an edematous swelling of the right vocal fold, appearing as a common Reinke edema. Surgery is the most common form of therapy, only a limited number of papers dealing with radio/chemotherapy exist due to the small number of cases. Unilateral cordectomy was performed, tumor was resected with negative surgical margins. This is the first report of an endolaryngeal myxofibrosarcoma. The tumor presented clinically as a unilateral swelling of the right vocal fold.

from the Journal of Voice

Vocal Fold Surface Hydration: A Review

Vocal fold surface liquid homeostasis contributes to optimal vocal physiology. In this paper we review emerging evidence that vocal fold surface liquid is maintained in part by salt and water fluxes across the epithelium. Based on recent immunolocalization and electrophysiological findings, we describe a transcellular pathway as one mechanism for regulating superficial vocal fold hydration. We propose that the pathway includes the sodium–potassium pump, sodium–potassium–chloride cotransporter, epithelial sodium channels, cystic fibrosis transmembrane regulator chloride channels, and aquaporin water channels. By integrating knowledge of the regulating mechanisms underlying ion and fluid transport with observations from hydration challenges and treatments using in vitro and in vivo studies, we provide a theoretical basis for understanding how environmental and behavioral challenges and clinical interventions may modify vocal fold surface liquid composition. We present converging evidence that clinical protocols directed at facilitating vocal fold epithelial ion and fluid transport may benefit healthy speakers, those with voice disorders, and those at risk for voice disorders.

from the Journal of Voice

Preliminary study on the quantitative analysis of vocal loading effects on vocal fold dynamics using phonovibrograms

from Annals of Otology, Rhinology, and Laryngology

OBJECTIVES: The purpose of the present study was to determine whether high-speed digital imaging with phonovibrogram (PVG) analysis would identify changes in vocal fold vibratory characteristics following prolonged reading (vocal fatigue) in subjects with normal voice to evaluate the voice effects of vocal loading. METHODS: Three healthy subjects’ larynges were examined with an endoscopic high-speed imaging system at 4 different levels of vocal load. Vocal fold dynamics were segmented and processed by PVGs. The PVG images were quantitatively described by a parameter set enabling an individual characterization of vocal fold dynamics. To reveal differences between the subjects, we performed a linear discrimination analysis. Within each subject, the identification of vocal loading effects was performed by statistical analysis (1-way analysis of variance), and 2-tailed paired t-tests were used as a consistency check between left and right vocal fold sides. RESULTS: For each subject, the PVG analysis enabled a precise quantification of the entire range of vocal fold dynamics. Independently of the high-speed videos (vocal loads), each subject could be identified by his or her PVG parameters on linear discrimination analysis. In all subjects, the effect of vocal loading was reflected by alterations of PVG parameters representing the posterior opening and closing dynamics. Evaluation within subjects revealed slight asymmetric vibratory behavior between the left and right vocal folds, confirming earlier assumptions. CONCLUSIONS: Within the investigated subjects, vocal loading does affect the vibratory characteristics of the vocal folds. Left-right vocal fold vibratory asymmetries do occur in healthy voices and can be identified by PVGs. High-speed digital imaging in combination with PVG analysis seems to be a promising tool for investigation of vocal fold fatigue and disorders resulting even from small dynamic changes.

A simple-shear rheometer for linear viscoelastic characterization of vocal fold tissues at phonatory frequencies

from the Journal of the Acoustical Society of America

Previous studies reporting the linear viscoelastic shear properties of the human vocal fold cover or mucosa have been based on torsional rheometry, with measurements limited to low audio frequencies, up to around 80 Hz. This paper describes the design and validation of a custom-built, controlled-strain, linear, simple-shear rheometer system capable of direct empirical measurements of viscoelastic shear properties at phonatory frequencies. A tissue specimen was subjected to simple shear between two parallel, rigid acrylic plates, with a linear motor creating a translational sinusoidal displacement of the specimen via the upper plate, and the lower plate transmitting the harmonic shear force resulting from the viscoelastic response of the specimen. The displacement of the specimen was measured by a linear variable differential transformer whereas the shear force was detected by a piezoelectric transducer. The frequency response characteristics of these system components were assessed by vibration experiments with accelerometers. Measurements of the viscoelastic shear moduli (G’ and G”) of a standard ANSI S2.21 polyurethane material and those of human vocal fold cover specimens were made, along with estimation of the system signal and noise levels. Preliminary results showed that the rheometer can provide valid and reliable rheometric data of vocal fold lamina propria specimens at frequencies of up to around 250 Hz, well into the phonatory range.