Neuromuscular induced phonation in a human <i>ex vivo</i> perfused larynx preparation

Berke, Gerald S.; Mendelsohn, Abie H.; Howard, N. Scott; Zhang, Zhaoyan

doi:10.1121/1.4776776

Cited by 14 publications

(15 citation statements)

References 7 publications

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“…Although these studies are able to reveal how different vibratory and acoustic measures vary with each other, they are unable to explain why such relationships occur and what biomechanical properties are required to produce the observed voice and vibration patterns. Experiments using physiological larynx models, either excised larynges (e.g., van den Berg and Tan, 1959;Isshiki, 1989) or in vivo models (e.g., Moore and Berke, 1988;Chhetri et al, 2012;Berke et al, 2013), have provided valuable insight toward the physics and control of voice production. However, manipulation of the larynx in these models, either mechanical or through nerve/muscle stimulation, often leads to complex and simultaneous changes in vocal fold stiffness, geometry, and glottal opening, which were often not monitored or measured.…”

Section: Introductionmentioning

confidence: 99%

Cause-effect relationship between vocal fold physiology and voice production in a three-dimensional phonation model

Zhang¹

2016

The Journal of the Acoustical Society of America

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The goal of this study is to better understand the cause-effect relation between vocal fold physiology and the resulting vibration pattern and voice acoustics. Using a three-dimensional continuum model of phonation, the effects of changes in vocal fold stiffness, medial surface thickness in the vertical direction, resting glottal opening, and subglottal pressure on vocal fold vibration and different acoustic measures are investigated. The results show that the medial surface thickness has dominant effects on the vertical phase difference between the upper and lower margins of the medial surface, closed quotient, H1-H2, and higher-order harmonics excitation. The main effects of vocal fold approximation or decreasing resting glottal opening are to lower the phonation threshold pressure, reduce noise production, and increase the fundamental frequency. Increasing subglottal pressure is primarily responsible for vocal intensity increase but also leads to significant increase in noise production and an increased fundamental frequency. Increasing AP stiffness significantly increases the fundamental frequency and slightly reduces noise production. The interaction among vocal fold thickness, stiffness, approximation, and subglottal pressure in the control of F0, vocal intensity, and voice quality is discussed.

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Section: Introductionmentioning

confidence: 99%

Cause-effect relationship between vocal fold physiology and voice production in a three-dimensional phonation model

Zhang¹

2016

The Journal of the Acoustical Society of America

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128

100

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“…7,8 As described, human larynges are recovered shortly following cardiac death and are re-perfused in order to maintain physiologic viability of the larynges. By applying neuromuscular electrical stimulation, physiologic laryngeal muscle activation was accomplished, and the feasibility has previously been described.…”

Section: Introductionmentioning

confidence: 99%

Preliminary Study of the Open Quotient in an Ex Vivo Perfused Human Larynx

Mendelsohn

Zhang

Luegmair

et al. 2015

JAMA Otolaryngol Head Neck Surg

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Importance Scientific understanding human voice production to date is a product of indirect investigations including animal models, cadaveric tissue study, or computational modeling. Due to its invasive nature, direct experimentation of human voice production has previously not been possible. The feasibility of an ex-vivo perfused human phonatory model has recently allowed systematic investigation in virtually living human larynges with parametric laryngeal muscle stimulation. Objective In this study, the relationship between adductor muscle group stimulation and the open quotient (OQ) of vocal fold vibration was investigated using an ex-vivo perfused human larynx. Design Human perfused tissue study. Setting Physiology Laboratory. Participants Human larynx is recovered from research-consented organ donors within two hours of cardiac death. Interventions, Main Outcomes and Measures Perfusion with donated human blood is re-established shortly after cardiac death. Human perfused phonation is achieved by providing subglottal airflow under graded neuromuscular electrical stimulation bilaterally to the intrinsic adductor groups and cricothyroid muscles. The phonation resulting from the graded states of neuromuscular stimulations are evaluated through high-speed vibratory imaging. OQ is derived through digital kymography and glottal area waveform analysis. Results Under constant glottal flow, step-wise increase in adductor muscle group stimulation decreased OQ. Quantitatively, OQ values reached a lower limit of 0.42. Increased stimulation above maximal muscle deformation was unable to affect OQ beyond this lower limit. Conclusions and Relevance For the first time in a neuromuscularly activated human larynx, a negative relationship between adductor muscle group stimulation and phonatory OQ was demonstrated. Further experience with the ex-vivo perfused human phonatory model will work to systematically define this causal relationship.

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“…While successful ELE has been conducted using fully perfused syringes in birds (Elemans et al, 2015) and fully perfused larynges in humans (Berke et al, 2013;Mendelsohn et al, 2015), much work remains to be done to achieve similar success in other mammalian species and other taxa (e.g. amphibians).…”

Section: Future Research Directions For Excised Larynx Experimentationmentioning

confidence: 99%

“…Most crucially, preparation of an excised larynx (unless performed on a fully perfused larynx which is kept in physiological conditions, allowing for muscular contractionssee Berke et al (2013) and Mendelsohn et al (2015) for humans and Elemans et al, (2015) for birds) removes the possibility for contractions of the intrinsic laryngeal muscles. In vivo, these muscles (Zemlin, 2001) are crucial for the (pre)phonatory configuration of vocal folds and the glottis, thus causally determining the vocal fold vibration dynamics and the spectral composition of the generated sound.…”

Section: Benefits and Pitfalls Of Excised Larynx Experimentationmentioning

confidence: 99%

Excised larynx experimentation: history, current developments, and prospects for bioacoustic research

Garcia

Herbst

2018

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The study of sound production mechanisms is a crucial, yet understudied, aspect of vocal communication research in vertebrates. In excised larynx experimentation (ELE), phonation is simulated ex vivo by forcing air through a larynx specimen mounted on a laboratory bench. The method provides unique insights into vocal production and allows inference of in vivo conditions. Here, we provide a historical overview of how this technique has been implemented, from antiquity to current state-of-theart setups. We review the advances made by applying ELE to human voice and biophysics research. We then highlight the promising research output resulting from ELE in animal bioacoustics, a research field that has largely overlooked the use of this method until very recently, but is now increasingly relying on this tool. We continue by discussing the limitations of ELE, depending on the focus of investigation. Finally, we suggest how this approach should be implemented and can be applied to various research questions. We conclude by underlining the value that ELE contributes to the comprehension of human voice as well as mammalian and avian vocal communication within an interdisciplinary approach.

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Neuromuscular induced phonation in a human ex vivo perfused larynx preparation

Cited by 14 publications

References 7 publications

Cause-effect relationship between vocal fold physiology and voice production in a three-dimensional phonation model

Cause-effect relationship between vocal fold physiology and voice production in a three-dimensional phonation model

Preliminary Study of the Open Quotient in an Ex Vivo Perfused Human Larynx

Excised larynx experimentation: history, current developments, and prospects for bioacoustic research

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