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

Abstract 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.