An easy-to-use laryngostroboscopy index for unilateral vocal fold paralysis reflects voice quality

BACKGROUND: To date, laryngostroboscopic parameters have been rarely used as outcome measures in clinical interventional studies, due tomethodological difficulties. METHODS: We applied a greatly reduced laryngostroboscopy evaluation protocol to an intervention study for unilateral vocal fold paralysis. Here,we investigate the correlation between the newly designed laryngostroboscopy index for unilateral vocal fold paralysis (LSI-UVFP) andan expert group's rating of voice quality. The LSI UVFP evaluates four key parameters closely related to voice production in UVFPpatients: (1) the vocal fold position, (2) the glottal gap during the closed phase, (3) atrophy of the paralysed vocal fold, and (4) themucosal wave. Each parameter is classified on a four-point ordinal scale: 0 for normal, 1 for mild, 2 for moderate, and 3 for severe. 52video recordings from 26 patients, before and after a voice improving surgery, were evaluated using the LSI-UVFP. RESULTS: The index demonstrates good reliability, with an intra-class correlation coefficient of 0.80. In addition, LSI-UVFP was found to show asignificant correlation with an auditory perceptual rating of voice quality. CONCLUSION: Thus, rating of laryngostroboscopy by the LSI-UVFP is a valid method for documenting and comparing therapeutic outcomes ininterventional studies for symptomatic UVFP. Its usage enables a meaningful interpretation of videolaryngostroboscopic data withregard to voice quality.