The spectrum of voice disorders – classification
Stephanie Martin in Working with Voice Disorders, 2020
There have been many approaches to the classification of voice disorders over the years, with experts attempting to find agreement on the best system of classification. The choice of a classification system may well be determined by the clinician’s place of work and working practice. This chapter explores the spectrum of voice disorders and offers practical descriptions of those disorders most commonly found on clinical caseloads. Mutational Falsetto has been variously described by authors as occurring in a post-adolescent male who continues to have a pre-adolescent voice, or as Juvenile Voice, when a post-adolescent female has the vocal qualities of a child. In the case of a post-adolescent male, it is also known as Puberphonia or Persistent Falsetto. Inducible Laryngeal Dysfunction, or Vocal Cord Dysfunction, typically involves abnormal adduction of the vocal folds during inspiration and mimics the symptoms of asthma with intermittent wheeze and dyspnoea.
The spectrum of voice disorders – presentation
Stephanie Martin in Working with Voice Disorders, 2020
This chapter outlines the vocal fold movement patterns or organic changes corresponding to the Voice Disorder classification. Where there is an organic disorder, the impairment to voice involves a lesion of the phonatory system, which may be congenital, inflammatory, traumatic, neoplastic or neurological. Vocal nodules are the result of vocal misuse, often due to excessive vocal loading with too short a recovery phase and inadequacy of the vocal system to sustain such demand. When there is a congenital laryngeal web, a disorder of voice may have been present since childhood, with little response to episodes of voice therapy due to the structural abnormality. Neurological disorders may often present initially as weakness of voice and reduction in vocal muscle tension with or without bowing of the vocal folds. It is the experience of the author that patients with Parkinson’s disease also frequently present with ventricular fold hyperadduction due to vocal fold inadequacy for the required phonatory environment.
Speech
Christopher J. Plack in The Sense of Hearing, 2018
Speech is the most important acoustic signal, and the perception of speech the most important function of the auditory system. The peripheral auditory system breaks sounds down into different frequency components, and the information regarding these components is transmitted along separate neural frequency channels. The auditory processes underlying speech perception are then considered, including neural mechanisms. It can exploit the rich speech code because it is highly sensitive to the spectral and temporal features of complex sounds. Sound is produced by forcing air from the lungs past the vocal folds, which are two bands of muscular tissue in the larynx. A vowel sound is a complex tone and therefore has a distinct fundamental frequency, determined by the rate of vibration of the vocal folds. Consonants are associated with restrictions in the flow of air through the vocal tract, caused by a narrowing or closure of a part of the vocal tract.
Viscoelastic measurements after vocal fold scarring in rabbits—short-term results after hyaluronan injection
Published in Acta Oto-Laryngologica, 2006
S. Hertegård, Å. Dahlqvist, E. Goodyer
Conclusions. The scarring model resulted in significant damage and elevated viscoelasticity of the lamina propria. Hyaluronan preparations may alter viscoelasticity in scarred rabbit vocal folds. Objectives. Vocal fold scarring results in stiffness of the lamina propria and severe voice problems. The aims of this study were to examine the degree of scarring achieved in the experiment and to measure the viscoelastic properties after injection of hyaluronan in rabbit vocal folds. Materials and methods. Twenty-two vocal folds from 15 New Zealand rabbits were scarred, 8 vocal folds were controls. After 8 weeks 12 of the scarred vocal folds received injections with 2 types of cross-linked hyaluronan products and 10 scarred folds were injected with saline. After 11 more weeks the animals were sacrificed. After dissection, 15 vocal folds were frozen for viscoelastic measurements, whereas 14 vocal folds were prepared and stained. Measurements were made of the lamina propria thickness. Viscoelasticity was measured on intact vocal folds with a linear skin rheometer (LSR) adapted to laryngeal measurements. Results. Measurements on the digitized slides showed a thickened lamina propria in the scarred samples as compared with the normal vocal folds (p <0.05). The viscoelastic analysis showed a tendency to stiffening of the scarred vocal folds as compared with the normal controls (p =0.05). There was large variation in stiffness between the two injected hyaluronan products.
Vocal fold wound healing after injection of human adipose-derived stem cells in a rabbit model
Published in Acta Oto-Laryngologica, 2011
Seok Jin Hong, Sang Hyuk Lee, Sung Min Jin, Soon Young Kwon, Kwang Yoon Jung, Min Kyung Kim, Ho Park, Kyo Won Lee
Conclusion: Injection of injured rabbit vocal folds with human adipose-derived stem cells (hADSCs) led to improved wound healing and fewer signs of scarring as demonstrated by a decreased collagen content in the treated folds compared with the untreated folds. hADSCs remained viable for up to 12 weeks in rabbit vocal folds. Objective: The aim of this study was to investigate the morphologic and histologic properties of scarred rabbit vocal folds following injection of hADSCs. Methods: This was a randomized, controlled animal study. Twenty-four vocal folds from 12 New Zealand rabbits were scarred using a CO2 laser and injected with either hADSCs (left vocal fold) or phosphate-buffered saline (right vocal fold). Every 4 weeks for the first 12 weeks after injection, an endoscopic examination was performed to assess the morphology of the vocal folds. Twelve weeks later the animals were euthanized and the tissues were stained for histology. Results: In comparison with the right vocal folds, there was significantly less granulation tissue in the hADSCs-injected left vocal folds (p < 0.05). Histological examination revealed excessive collagen deposition and perichondral fibrosis in the right vocal folds, whereas the left vocal folds exhibited better wound healing and less collagen deposition (p < 0.05). Among the 12 specimens injected with hADSCs, 4 specimens demonstrated viable hADSCs under immunofluorescent cytochemistry.
Activation of vocal fold healing with topical vitamin A in rabbits
Published in Acta Oto-Laryngologica, 2009
Ozgur Akdogan, Adin Selcuk, Ibrahim Ozcan, Kürsat Murat Ozcan, Seren Gulsen Giray, Huseyin Dere, Candan Ozogul
Conclusion. The results suggest that vitamin A can prevent scar formation in the vocal fold after surgery. Objectives. This study aimed to evaluate the effects of topically applied vitamin A on healing after vocal fold trauma. Materials and methods. Vocal folds of 20 adult rabbits were traumatized unilaterally. Ten of them were treated with topical application of vitamin A and the others served as controls. All animals were sacrificed after 10 days. Vocal folds were resected for analysis by light microscopy. Results. The untreated vocal folds showed extensive deposition of collagen and fibroblast on light microscopy and vocal folds treated with vitamin A showed less deposition. There was a significant difference between the two groups according to the percentage of collagen and fibroblasts in the lamina propria (p<0.01).
Related Knowledge Centers
- Phonation
- Larynx
- Vagus Nerve
- Mucous Membrane