Vocal fold vibration measurements using laser Doppler vibrometry

Abstract

The objective of this study was to measure the velocity of the superior surface of human vocal folds during phonation using laser Doppler vibrometry (LDV). A custom-made endoscopic laser beam deflection unit was designed and fabricated. An in vivo clinical experimental procedure was developed to simultaneously collect LDV velocity and video from videolaryngoscopy. The velocity along the direction of the laser beam, i.e., the inferior-superior direction, was captured. The velocity was synchronous with electroglottograph and sound level meter data. The vibration energy of the vocal folds was determined to be significant up to a frequency of 3 kHz. Three characteristic vibrational waveforms were identified which may indicate bifurcations between vibrational modes of the mucosal wave. No relationship was found between the velocity amplitude and phonation frequency or sound pressure level. A correlation was found between the peak-to-peak displacement amplitude and phonation frequency. A sparse map of the velocity amplitudes on the vocal fold surface was obtained.

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

“…48 Local parameters: Displacement and velocity values (Fig. 6) are in similar ranges to earlier ex-vivo 17,18 and in-vivo canine 19 hemilarynx studies, in-vivo human investigations, 12 and synthetic models. 22 The displacement ratios (lateral/vertical amplitudes) for L1 and L2 are up to 2.1, as seen in other studies.…”

“…4,5 In-vivo and ex-vivo analysis of the full larynx during phonation mainly permits observation, imaging, and quantification of the superior surface of the vocal folds and the vocal fold edges. [6][7][8] Although such studies yield detailed quantitative information about vocal fold dynamics, [9][10][11][12][13] several crucial aspects of vocal dynamics, such as mucosal wave propagation along the medial surface and the convergentdivergent shape change of the glottal duct, can barely be captured from the top view. [14][15][16] The hemilarynx methodology was developed to yield optical access to the entire surface dynamics of the vocal folds during phonation.…”

Experimental methods for the characterization of the frequency-dependent viscoelastic properties of soft materials

“…The fundamental frequency of vocal fold vibrations can reach up to a few kHz in singing (Titze, 1994). Laser Doppler velocimetry of the human vocal folds during phonation has revealed significant vibration energy at frequencies up to 3 kHz (Chan et al, 2013). Therefore, the mechanical properties of vocal fold tissue and injectable biomaterials used for vocal fold repair need to be characterized at frequencies up to 3 kHz.…”

Estimation of inferior-superior vocal fold kinematics from high-speed stereo endoscopic data in vivo

“…Laser systems, on the other hand, have been applied to quantitatively measure the vocal fold motion in conjunction with a high-speed video camera. For laser systems focused on a single point, 11,12 two points, 13 or a line, 14,15 proper positioning of the limited target points on the vocal folds is paramount, as the inferior-superior behavior depends upon the measurement location on the vocal folds. This difficulty is resolved by a system of laser dots uniformly distributed on a planar area.…”