Laryngeal High-Speed Videoendoscopy: Sensitivity of Objective Parameters towards Recording Frame Rate

Abstract

The current use of laryngeal high-speed videoendoscopy in clinic settings involves subjective visual assessment of vocal fold vibratory characteristics. However, objective quantification of vocal fold vibrations for evidence-based diagnosis and therapy is desired, and objective parameters assessing laryngeal dynamics have therefore been suggested. This study investigated the sensitivity of the objective parameters and their dependence on recording frame rate. A total of 300 endoscopic high-speed videos with recording frame rates between 1000 and 15 000 fps were analyzed for a vocally healthy female subject during sustained phonation. Twenty parameters, representing laryngeal dynamics, were computed. Four different parameter characteristics were found: parameters showing no change with increasing frame rate; parameters changing up to a certain frame rate, but then remaining constant; parameters remaining constant within a particular range of recording frame rates; and parameters changing with nearly every frame rate. The results suggest that (1) parameter values are influenced by recording frame rates and different parameters have varying sensitivities to recording frame rate; (2) normative values should be determined based on recording frame rates; and (3) the typically used recording frame rate of 4000 fps seems to be too low to distinguish accurately certain characteristics of the human phonation process in detail.

Clinical relevance of endoscopic three‐dimensional imaging for quantitative assessment of phonation

“…Common laryngoscopic examinations are performed by the use of 2D imaging techniques such as stroboscopy, videokymography, and high‐speed videoendoscopy (HSV) . As shown in Figure , the recordings are intrinsically limited to resolve the lateral and longitudinal view of the vocal folds' behavior.…”

“…[15][16][17][18] Common laryngoscopic examinations are performed by the use of 2D imaging techniques such as stroboscopy, videokymography, and high-speed videoendoscopy (HSV). [19][20][21][22][23][24] As shown in Figure 1, the recordings are intrinsically limited to resolve the lateral and longitudinal view of the vocal folds' behavior. By these means, the majority of vocal fold pathologies, such as neoplasia, paresis, inflammation, malformation, and atrophy, are recognizable.…”

Influence of Analyzed Sequence Length on Parameters in Laryngeal High-Speed Videoendoscopy

“…Sci. 2018, 8, 2666 3 of 17 both can be influenced by different factors [34][35][36][37][38]. One of these factors is the recording frame rate, which was already investigated for acoustic and GAW signals.…”

“…For acoustic measures, a sampling frequency of at least 26 kHz was suggested to avoid the introduction of errors [34]. For GAW signals it is reported that up to 90% of parameters were affected by the changes in the frame rate [35]. That study suggested that normative parameter values based on the recording frame rate should be determined and a recording frequency of 4000 Hz seemed to be too low to register all details of vocal fold vibratory patterns.…”

Endoscopic Laser-Based 3D Imaging for Functional Voice Diagnostics

“…Typical vocal fold vibrations display a frequency in the range of 80-300 Hz for normal phonation. In order to capture such rapid movements adequately, high-speed videoendoscopy (HSV) with frame rates in the range of 4-20 kHz is used [3][4][5][6][7]. In the clinical routine, the most common methods for an evaluation of the vocal fold physiology and dynamical behavior are based on endoscopic, two-dimensional imaging (see Figure 1, left).…”