Aerodynamic and Acoustic Effects of False Vocal Folds and Epiglottis in Excised Larynx Models

Alipour, Fariborz; Jaiswal, Sanyukta; Finnegan, Eileen M.

doi:10.1177/000348940711600210

Cited by 55 publications

(63 citation statements)

References 8 publications

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“…Because of the linear correlation between these two parameters, as displayed in the top row of Fig. 3, which has also been reported by Alipour and colleagues, 28,30,32,40 flow leakage in the setup was ruled out for all three larynges. The control variable for the succeeding measurements was subglottal pressure P S , which was kept constant during each experimental run.…”

Section: Discussionmentioning

confidence: 56%

“…In the context of vocal fold adduction, different studies reported similar systematic results for both definitions of glottal flow resistance, i.e., increased glottal adduction resulted in increased flow resistance. 30,32 However, when investigating the impact of the ventricular folds, different behaviors for R A and R B were reported: Whereas Alipour et al 40 found increased flow resistance R A in the presence of the ventricular folds compared with configurations without ventricular vocal folds, Zhang et al 43 reported a decrease of glottal flow resistance R B . In a later study, Zheng et al 42 showed that these different findings, for small flow rates, result from the different definitions of R A and R B .…”

Section: Discussionmentioning

confidence: 99%

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Dynamic vocal fold parameters with changing adduction in ex-vivo hemilarynx experiments

Döllinger

Berry

Kniesburges

2016

The Journal of the Acoustical Society of America

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Ex-vivo hemilarynx experiments allow the visualization and quantification of three-dimensional dynamics of the medial vocal fold surface. For three excised human male larynges, the vibrational output, the glottal flow resistance, and the sound pressure during sustained phonation were analyzed as a function of vocal fold adduction for varying subglottal pressure. Empirical eigenfunctions, displacements, and velocities were investigated along the vocal fold surface. For two larynges, an increase of adduction level resulted in an increase of the glottal flow resistance at equal subglottal pressures. This caused an increase of lateral and vertical oscillation amplitudes and velocity indicating an improved energy transfer from the airflow to the vocal folds. In contrast, the third larynx exhibited an amplitude decrease for rising adduction accompanying reduction of the flow resistance. By evaluating the empirical eigenfunctions, this reduced flow resistance was assigned to an unbalanced oscillation pattern with predominantly lateral amplitudes. The results suggest that adduction facilitates the phonatory process by increasing the glottal flow resistance and enhancing the vibrational amplitudes. However, this interrelation only holds for a maintained balanced ratio between vertical and lateral displacements. Indeed, a balanced vertical-lateral oscillation pattern may be more beneficial to phonation than strong periodicity with predominantly lateral vibrations.

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Section: Discussionmentioning

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Dynamic vocal fold parameters with changing adduction in ex-vivo hemilarynx experiments

Döllinger

Berry

Kniesburges

2016

The Journal of the Acoustical Society of America

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“…This radiated vocal power (and the associated SPL of 80-90dB at a distance of 15-18cm from the larynx) is remarkable only because the fundamental frequency is so low. Large canine larynges have produced an SPL of 82dB at a similar distance, but only with at least twice the subglottal pressure and at least twice the fundamental frequency (Alipour et al, 2007). Considering an increase of 6dB per doubling of subglottal pressure and another increase of 6dB for doubling of F 0 (Titze and Sundberg, 1992), we would expect on the order of 100dB for the tiger compared with 82dB for the canine.…”

Section: Discussionmentioning

confidence: 95%

Vocal power and pressure–flow relationships in excised tiger larynges

Titze

Fitch

Hunter

et al. 2010

Journal of Experimental Biology

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SUMMARYDespite the functional importance of loud, low-pitched vocalizations in big cats of the genus Panthera, little is known about the physics and physiology of the mechanisms producing such calls. We investigated laryngeal sound production in the laboratory using an excised-larynx setup combined with sound-level measurements and pressure-flow instrumentation. The larynges of five tigers (three Siberian or Amur, one generic non-pedigreed tiger with Bengal ancestry and one Sumatran), which had died of natural causes, were provided by Omaha's Henry Doorly Zoo over a five-year period. Anatomical investigation indicated the presence of both a rigid cartilaginous plate in the arytenoid portion of the glottis, and a vocal fold fused with a ventricular fold. Both of these features have been confusingly termed 'vocal pads' in the previous literature. We successfully induced phonation in all of these larynges. Our results showed that aerodynamic power in the glottis was of the order of 1.0W for all specimens, acoustic power radiated (without a vocal tract) was of the order of 0.1mW, and fundamental frequency ranged between 20 and 100Hz when a lung pressure in the range of 0-2.0kPa was applied. The mean glottal airflow increased to the order of 1.0ls -1 per 1.0kPa of pressure, which is predictable from scaling human and canine larynges by glottal length and vibrational amplitude. Phonation threshold pressure was remarkably low, on the order of 0.3kPa, which is lower than for human and canine larynges phonated without a vocal tract. Our results indicate that a vocal fold length approximately three times greater than that of humans is predictive of the low fundamental frequency, and the extraordinarily flat and broad medial surface of the vocal folds is predictive of the low phonation threshold pressure.

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“…Tsai et al, 2008). It is likely that they are also involved in nonhuman primate phonation, in particular in high-amplitude screaming (van den Berg, 1955;Agarwal et al, 2003;Alipour et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Elasticity and stress relaxation of rhesus monkey (Macaca mulatta) vocal folds

Riede

2010

Journal of Experimental Biology

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SUMMARYFundamental frequency is an important perceptual parameter for acoustic communication in mammals. It is determined by vocal fold oscillation, which depends on the morphology and viscoelastic properties of the oscillating tissue. In this study, I tested if stress-strain and stress-relaxation behavior of rhesus monkey (Macaca mulatta) vocal folds allows the prediction of a species' natural fundamental frequency range across its entire vocal repertoire as well as of frequency contours within a single call type. In tensile tests, the load-strain and stress-relaxation behavior of rhesus monkey vocal folds and ventricular folds has been examined. Using the string model, predictions about the species' fundamental frequency range, individual variability, as well as the frequency contour of 'coo' calls were made. The low-and mid-frequency range (up to 2kHz) of rhesus monkeys can be predicted relatively well with the string model. The discrepancy between predicted maximum fundamental frequency and what has been recorded in rhesus monkeys is currently ascribed to the difficulty in predicting the behavior of the lamina propria at very high strain. Histological sections of the vocal fold and different staining techniques identified collagen, elastin, hyaluronan and, surprisingly, fat cells as components of the lamina propria. The distribution of all four components is not uniform, suggesting that different aspects of the lamina propria are drawn into oscillation depending on vocal fold tension. A differentiated recruitment of tissue into oscillation could extend the frequency range specifically at the upper end of the frequency scale.

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Aerodynamic and Acoustic Effects of False Vocal Folds and Epiglottis in Excised Larynx Models

Abstract: The addition of the supraglottic laryngeal structures has a significant impact on both aerodynamic and acoustic characteristics of excised larynges.

Cited by 55 publications

References 8 publications

Dynamic vocal fold parameters with changing adduction in ex-vivo hemilarynx experiments

Dynamic vocal fold parameters with changing adduction in ex-vivo hemilarynx experiments

Vocal power and pressure–flow relationships in excised tiger larynges

Elasticity and stress relaxation of rhesus monkey (Macaca mulatta) vocal folds

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