This study used visual analog scales to obtain perceptual ratings of features of voice production in subjects with unilateral vocal fold paralysis (UVFP), including clarity of laryngeal articulation, consistency of loudness across the utterance and the voiced/voiceless distinction. Recordings of repeated /i/, /isi/, and /izi/ from subjects diagnosed with UVFP and control subjects were randomly re-recorded, and then rated by five listeners. Significant differences in ratings (Smirnov test, p < 0.01) were found between groups for “aphonia”, “severity”, “clarity of articulation”, “overall loudness”, “consistency of loudness” and “amount of effort”. Four of five raters agreed on the accuracy of /s/ or /z/ productions for only 54% of the samples from the subjects with UVFP. Voiceless and voiced cognates were equally likely to be rated as inaccurate. Results suggested that these variables were sensitive to changes in voice production resulting from paralysis, and may be useful in measuring treatment outcomes and spontaneous recovery of function.

Learning outcomes:

As a result of reading this manuscript the reader will (1) gain an understanding of types of perceptual scales and how to develop the set of vocal characteristics to be used in distinguishing patients with UVFP and those without, (2) learn which vocal characteristics listeners are able to use to successfully distinguish between patients with UVFP and those without and (3) understand the possible role for perceptual ratings in tracking changes in vocal characteristics in subjects over time following treatment or spontaneous recovery of function.