How do ventricular folds behave during vocal effort ?

International audienceThe human two ventricular folds constitute an additional laryngeal vibrator, whose biomechanical properties differ from those of the vocal folds. Often considered solely anecdoticaly, they may adduct, get into contact, and even vibrate during speech and singing. This present study aims at characterizing their behavior during situations of vocal effort, such as shouted speech, growls, and crescendos-decrescendos. A database of phonatory gestures which accompanies vocal effort has been constituted by the cinematographic, audio and electroglottographic recordings of five speakers and three singers. The signals have been recorded simultaneously and synchronized to the high-speed laryngeal images. A ventricular-fold systematic movement is observed during vocal effort, as compared to usual phonation. The two folds get closer, and this movement may go with a spectral increase of energy in the 2-4 kHz frequency band with no direct correlation on vocal intensity. The closing movement is either localized on the median and/or antero-median part, or it may occur over the whole fold length. In the case of contact, the ventricular folds may start to vibrate, periodically or not, and in phase or not with the vocal-folds vibratory movement. Using an aerodynamical theoretical approach, the influence of a supra-laryngeal constriction on the glottal vibratory movement has been evidenced (Bailly et al., 2008). This aerodynamical modeling approach is combined here with high-speed visualization in order to predict the physical impact of the observed ventricular constrictions on glottal vibration, similarly to a previous study on period-doubling phonation (Bailly et al., 2010). Ventricular area is detected on high-speed laryngeal images, and given as an input parameter to the model. Glottal vibratory behavior is then simulated by applying a two-mass model inspired from Ruty et al. (2007). The resulting signal is compared with glottal contact area as measured by electroglottography. Bailly, L., Pelorson, X., Henrich, N., and Ruty, N. (2008). "Influence of a constriction in the near field of the vocal folds: Physical modeling and experimental validation," J. Acoust. Soc. Am. 124(5), 3296-3308. Bailly, L. (2009). "Vocal fold and ventricular fold vibration in period-doubling phonation: Physiological description and aerodynamic modeling," J. Acoust. Soc. Am. 127(5), 3212-3222. Ruty, N., Pelorson, X., Van Hirtum, A., Lopez-Arteaga, I., and Hirschberg, A. (2007). "An "in-vitro‟ setup to test the relevance and the accuracy of low-order vocal folds models," J. Acoust. Soc. Am. 121 (1), 479-490

The Ventricular-Fold Dynamics in Human Phonation

International audiencePurpose: In this study, the authors aimed (a) to provide a classification of the ventricular-fold dynamics during voicing, (b) to study the aerodynamic impact of these motions on vocal-fold vibrations, and (c) to assess whether ventricularfold oscillations could be sustained by aerodynamic coupling with the vocal folds. Method: A 72-sample database of vocal gestures accompanying different acoustical events comprised highspeed cinematographic, audio, and electroglottographic recordings of 5 subjects. Combining the physiological correlates with a theoretical model of phonation, the vocal-ventricular aerodynamic interactions were investigated. Results: A ventricular-fold motion is found during (de)crescendos, shout, throat singing, yodel, growls, and glides with transitions between registers. Three main types of dynamics are identified: slow nonoscillatory motion and fast oscillatory motion with aperiodical or periodical vibrations. These patterns accompany a change in voice quality, pitch, and/or intensity. Alterations of glottal-oscillatory amplitude, frequency, and contact were predicted. It is shown that a ventricular oscillation can be initiated and sustained by aerodynamic coupling with the vocal folds. Conclusions: Vocal-ventricular aerodynamic interactions can alter, enhance, or suppress vocal-fold vibrations or leave them unchanged, depending on the ventricular-fold dynamics involved. Depending on its variation in time, a similar level of ventricular-fold adduction impacts the glottal vibratory magnitude and contact much differently

Assessment of 3D elasticity data of the larynx for FE models of phonation

National audienceThe quality of numeric models of phonation is strongly dependent on the accuracy of geometric and elastic tissue data because of the inhomogeneous and anisotropic nature of these structures. The dynamic elasticity of the vocal folds can be assessed in vivo and in vitro with a linear skin rheometer. This method has been applied in parallel and normal to the vocal fold surface of excised larynges. The data was collected in several directions and for two layers of the tissues which provides a base for a finite-element model. The results of the measurements are presented and consequences for the simulations are discussed

Cross-Validation and Normative Values for the German Vocal Tract Discomfort Scale

Purpose The Vocal Tract Discomfort Scale (VTD Scale) is a self-rating questionnaire investigating physical symptoms in the larynx associated with vocal pathology. The aim of this work was to investigate the reliability, validity, sensitivity, and specificity of the first German version and to provide normative data with thresholds for pathology and a scaling scheme. Study Design A retrospective multicenter study was performed. Method A total of 571 participants (409 female and 162 male), with a mean age of 47.2 years, were recruited at three German centers; of these, there were 447 participants with voice disorder and 124 vocally healthy participants. The clinical examination consisted of patient history, visual laryngeal examination, acoustic and aerodynamic assessment, perceptual analysis by the Grading-Roughness-Breathiness-Asthenia-Strain Scale, and subjective evaluation using the VTD Scale and the Voice Handicap Index (VHI). Statistics included group comparisons (t test and analysis of variance), Pearson correlation coefficient (between VTD Scale and VHI), and Cronbach's alpha to assess validity and reliability. Analysis of receiver operating characteristics was performed to examine VTD Scale's discriminatory ability and provide a cutoff score. Additionally, percentiles were applied to provide VTD Scale ranges. Results There were highly significant differences between healthy participants and participants with voice disorder regarding the total score and both subscales of the VTD Scale. Internal consistency was excellent (α = .928). We found moderate, positive correlation between the VTD Scale and VHI (ρ = .596, p < .001). Receiver operating characteristics analysis showed an area under the curve of 0.876 (p < .001, 95% confidence interval [0.846, 0.906]). VTD Scale ranges were no (score: 0–13), mild (score: 14–26), moderate (score: 27–40), and severe (score: 41–96) disorder. Conclusions Results confirm an excellent reliability and validity of the German VTD Scale. It provides additional and independent diagnostic information and is a useful instrument to complement voice assessment. The scaling into four severity subgroups allows the tool to be used for screening patients and considers a transferral to a voice specialist

Frequency-specific Animal Sound Test (FAST) 4: A valid method for hearing screening

Objectives: It is essential to monitor hearing status in children not only as a mandatory requirement during universal newborn hearing screening (UNHS), but also later during preschool and school-age development. The present study considers the appropriateness of the Frequency-specific Animal Sound Test (FAST4) for use in children between the ages of 2.5 and 10 years; the comparability of hearing thresholds determined using FAST4 and those measured by pure tone audiometry (PTA); and the clinical and diagnostic utility of FAST4 in a variety of pediatric settings. Methods: 322 children aged 2.6-14.1 years and 41 adults were tested with FAST4. Four animal sounds were presented via headphones and a hearing threshold was determined for the high and low frequency range. In addition, the hearing threshold of each child was measured by PTA. Results: Results were analyzed from 156 normal-hearing and hearing-impaired children, mostly above the age of 4 years. In general, FAST4 yielded hearing levels comparable with those from PTA in children and in adults. FAST4 frequently had to be halted prematurely in children under 4 years old. Conclusions: FAST4 is a strong candidate for use as an instrument for preschool hearing screening and offers several advantages over other hearing tests. FAST4 permits simple, swift and efficient determination of the hearing threshold and the test can be administered by staff without specialist training. A number of improvements have already been integrated into the successor model known as mFAST. (C) 2015 Elsevier Ireland Ltd. All rights reserved

The anisotropic nature of the human vocal fold: an ex vivo study

Universitat Klinic Eppendorf GermanyThe purpose of this study was to measure the relationship between the shear elastic properties of vocal fold with respect to the direction of applied stress. There is extensive published material that quantifies the shear viscoelastic properties of the vocal fold, but as much of these data were obtained using rotating parallel plate rheometers, which are unable to resolve out difference of the shear elastic behaviour with respect to direction, there is very little data that indicates anisotropic behaviour. To overcome this gap in knowledge, the team devised an apparatus that is capable of applying a shear stress in a known direction. A series of measurements were taken at the mid-membranous position, in the transverse and longitudinal directions. Point-specific measurements were performed using fourteen human cadaver excised larynges, which were hemi-sectioned to expose the vocal fold. An extremely low sinusoidal shear force of 1 g was applied tangentially to the membrane surface in both the longitudinal and transverse direction, and the resultant shear strain was measured. With the probe applied to the intact vocal fold, the average ratio of the elasticity in the transverse with respect to the longitudinal direction was 0.55. Further investigation using histological staining of collagens in the lamina propria indicates that there is a visible difference in the general alignment of collagen fibres when comparing the coronal and the sagittal sections. Our conclusion is that there is a quantifiable difference between the shear elastic response of the lamina propria in the longitudinal and transverse directions, and that this could be explained by the difference in alignment of collagen fibres within the lamina propria.EPSRC ; THE ROYAL SOCIET