Sensitivity of Videolaryngostroboscopic Rating Tools to Differences in Dysphonia Severity

Objectives This study evaluated the validity of two videolaryngostroboscopic (VLS) rating tools to detect differences in VLS ratings between normophonic speakers, mild, and moderate-severely dysphonic speakers. Methods Sixteen rigid VLS exams were obtained from four normophonic controls and 12 speakers with dysphonia (8 =mild, 4 =moderate-severe) secondary to laryngeal pathology. Eight clinicians rated nine vibratory VLS parameters for each exam using both the Voice-vibratory Assessment of Laryngeal Imaging (VALI) tool and a 100 mm visual analog scales (VAS). Ratings obtained for both right and left vocal folds (eg, mucosal wave, amplitude of vibration, nonvibrating portion) were averaged. One rating of overall severity of laryngeal function using a 100 mm VAS also was obtained. ANOVAs were used to evaluate differences in VLS parameters between three speaker groups (normophonic, mildly dysphonic, moderate-severely dysphonic) using these two rating tools. Results There were statistically significant differences between controls and moderate-severely dysphonic speakers and for all VLS parameters except phase symmetry (P < 0.05) for both VALI and VAS ratings. Differences between mildly dysphonic and moderate-severely dysphonic and speakers were observed for 4/6 VALI ratings (mucosal wave, nonvibratory portions, phase closure, and regularity) and 5/6 parameters (mucosal wave, amplitude of vibration, nonvibratory portions, phase closure, and regularity) for VAS ratings. Significant differences between controls and mildly dysphonic speakers were not observed for VLS parameter rated using the VALI. There were significant differences between controls and mildly dysphonic speakers for 3/6 parameters (mucosal wave, amplitude of vibration, nonvibratory portion) using a VAS. Ratings of overall severity of laryngeal function differed between all levels of dysphonia severity. Conclusions Significant differences in VLS ratings were observed for comparisons of normophonic and moderate-severely dysphonic speakers and mild to moderately dysphonic speakers using the VALI and the VAS. However, the VAS scale appeared to better differentiate differences in VLS measures between normophonic speakers and those with mild dysphonia. Future studies should consider rating scale sensitivity when VLS rating tools are selected for clinical and research purposes.