Estimating Vocal Fold Contact Pressure from Raw Laryngeal High-Speed Videoendoscopy Using a Hertz Contact Model

Abstract

The development of trauma-induced lesions of the vocal folds (VFs) has been linked to a high collision pressure on the VF surface. However, there are no direct methods for the clinical assessment of VF collision, thus limiting the objective assessment of these disorders. In this study, we develop a video processing technique to directly quantify the mechanical impact of the VFs using solely laryngeal kinematic data. The technique is based on an edge tracking framework that estimates the kinematic sequence of each VF edge with a Kalman filter approach and a Hertzian impact model to predict the contact force during the collision. The proposed formulation overcomes several limitations of prior efforts since it uses a more relevant VF contact geometry, it does not require calibrated physical dimensions, it is normalized by the tissue properties, and it applies a correction factor for using a superior view only. The proposed approach is validated against numerical models, silicone vocal fold models, and prior studies. A case study with high-speed videoendoscopy recordings provides initial insights between the sound pressure level and contact pressure. Thus, the proposed method has a high potential in clinical practice and could also be adapted to operate with laryngeal stroboscopic systems.

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

“…Most bench-top studies have used canine excised larynx setups as models from which direct measures of contact pressures have been obtained and correlated with other measures such as the electroglottography-based contact quotient [ 38 ] and HSV-derived vocal fold tissue acceleration [ 33 , 39 ]. Researchers continue to explore indirect methods to estimate vocal fold contact pressures to facilitate this process in vivo [ 16 , 17 , 36 ]; but efforts in that direction require further validation with direct contact pressure measurements.…”

“…Although limitations exist when using non-perfused laryngeal tissue and simulated phonation, the hemilarynx methodology was applied to facilitate quantitative measurements of the medial surface dynamics of the vocal folds [11]. High-speed digital imaging of the vocal folds has been applied in several studies in the literature to characterize the kinematics of the medial surface of excised human and animal tissue models [22][23][24][25][26][27][28][29], as well as during in vivo phonation [17]. Figure 4 illustrates the preparation of the hemilarynx that allowed for two simultaneous views (top-down and medial) during self-sustained vocal fold oscillation.…”

“…Accurate positioning of the intraglottal pressure sensor is expected to provide new insight into how collision pressure contributes to vocal fold trauma (e.g., how collision pressure varies with sound pressure level) and lead to the development of new measures that could improve prevention, diagnosis and treatment of phonotraumatic disorders. These data could also be used to help improve physical and computational models of voice production [13][14][15][16][17]. Figure 1 displays a photograph of the dual-sensor ISP probe and its dimensions.…”

An acoustic source model for asymmetric intraglottal flow with application to reduced-order models of the vocal folds

“…Speech production is the result of complex interactions between flow, tissue, and sound, affecting the vocal fold (VF) dynamics, kinematics, aerodynamics, and radiated pressure at the mouth [1]. Approaches describing these interactions have been applied in models of speech production to study normal and pathological speech [2], and have become relevant clinical tools [3–7]. However, very few studies have been devoted to validate model predictions with comprehensive recordings in human subjects.…”

Laryngeal Image Processing of Vocal Folds Motion

“…• It is used to examine the basic physiology of different singing styles, such as extremely high-pitched singing, throat singing, or different pop and rock styles [40], and to study the oscillatory characteristics of the vocal folds across classical soprano and tenors singers [41,42]. • It is useful to get insights into tissue vibratory characteristics, influence of aerodynamical forces and muscular tension, vocal length, phonatory breaks, laryngeal spams, vocal folds contact and evaluation of normal laryngeal functioning in situation of rapid pitch change such as onset and offset of voicing or glides [5,43].…”