Automated Measurement of Vocal Fold Vibratory Asymmetry From High-Speed Videoendoscopy Recordings

Abstract

Purpose In prior work, a manually derived measure of vocal fold vibratory phase asymmetry correlated to varying degrees with visual judgments made from laryngeal high-speed videoendoscopy (HSV) recordings. This investigation extended this work by establishing an automated HSV-based framework to quantify 3 categories of vocal fold vibratory asymmetry. Method HSV-based analysis provided for cycle-to-cycle estimates of left–right phase asymmetry, left–right amplitude asymmetry, and axis shift during glottal closure for 52 speakers with no vocal pathology producing comfortable and pressed phonation. An initial cross-validation of the automated left–right phase asymmetry measure was performed by correlating the measure with other objective and subjective assessments of phase asymmetry. Results Vocal fold vibratory asymmetry was exhibited to a similar extent in both comfortable and pressed phonations. The automated measure of left–right phase asymmetry strongly correlated with manually derived measures and moderately correlated with visual–perceptual ratings. Correlations with the visual–perceptual ratings remained relatively consistent as the automated measure was derived from kymograms taken at different glottal locations. Conclusions An automated HSV-based framework for the quantification of vocal fold vibratory asymmetry was developed and initially validated. This framework serves as a platform for investigating relationships between vocal fold tissue motion and acoustic measures of voice function.