Toward Development of a Vocal Fold Contact Pressure Probe: Bench-Top Validation of a Dual-Sensor Probe Using Excised Human Larynx Models.

Daryush D Mehta,James B Kobler,Matías Zañartu,Mohsen Motie-Shirazi,Sean D Peterson,Byron D Erath,Robert H Petrillo,Steven M Zeitels,Robert E Hillman

doi:10.3390/app9204360

Abstract

A critical element in understanding voice production mechanisms is the characterization of vocal fold collision, which is widely considered a primary etiological factor in the development of common phonotraumatic lesions such as nodules and polyps. This paper describes the development of a transoral, dual-sensor intraglottal/subglottal pressure probe for the simultaneous measurement of vocal fold collision and subglottal pressures during phonation using two miniature sensors positioned 7.6 mm apart at the distal end of a rigid cannula. Proof-of-concept testing was performed using excised whole-mount and hemilarynx human tissue aerodynamically driven into self-sustained oscillation, with systematic variation of the superior–inferior positioning of the vocal fold collision sensor. In the hemilarynx experiment, signals from the pressure sensors were synchronized with an acoustic microphone, a tracheal-surface accelerometer, and two high-speed video cameras recording at 4000 frames per second for top-down and en face imaging of the superior and medial vocal fold surfaces, respectively. As expected, the intraglottal pressure signal exhibited an impulse-like peak when vocal fold contact occurred, followed by a broader peak associated with intraglottal pressure build-up during the de-contacting phase. As subglottal pressure was increased, the peak amplitude of the collision pressure increased and typically reached a value below that of the average subglottal pressure. Results provide important baseline vocal fold collision pressure data with which computational models of voice production can be developed and in vivo measurements can be referenced.

Highlights

Many common voice disorders are believed to be primarily the result of vocal behaviors associated with voice misuse/overuse that result in vocal fold tissue trauma, or phonotrauma
This paper reports on the proof of concept of a new in vivo dual-sensor intraglottal/subglottal pressure (ISP) probe that was validated using excised whole-mount and hemilarynx phonatory models
Of interest to real-time in vivo ISP probe placement, the dual-sensor probe configuration can aid in determining correct sensor placement because the signal dual-sensor probe configuration can aid in determining correct sensor placement because the signal waveshape exhibited at the intraglottal location was differentiated from the subglottal sensor signal

Summary

Introduction

Many common voice disorders are believed to be primarily the result of vocal behaviors associated with voice misuse/overuse that result in vocal fold tissue trauma, or phonotrauma. Vocal fold impact stress (in the direction of tissue motion) and shear stress (along the tissue surface) are assumed to be critical factors in causing phonotrauma [2,4,5,6], there is a paucity of empirical data for these forces, including information about the actual levels that cause tissue trauma This lack of data is largely because the in vivo measurement of vocal fold impact forces and pressures during phonation has proven challenging, and only a few published studies have been able to successfully measure vocal fold collision characteristics via intraglottally positioned devices [7,8,9]. Accurate positioning of the sensor in the vertical (superior–inferior) direction was critical and was accomplished using simultaneous laryngeal imaging using a rigid, transoral endoscope held in the contralateral hand of the endoscopist

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