Effect of Anchor Voices and Listener Expertise on Auditory-Perceptual Judgments of Voice Quality Using the GRBAS Scale

Abstract

This study aimed to determine the effect of anchor voices and listener expertise on auditory-perceptual judgment of voice quality using the GRBAS scale. This study utilized a modified crossover design with counterbalancing. Anchor voices for each parameter of the GRBAS scale were chosen based on expert consensus. A total of 28 participants were divided into three groups based on their expertise. The first and second groups consisted of nine undergraduate (UG) and nine postgraduate (PG) students of speech-language pathology. The third group consisted of 10 practicing speech-language pathologists (SLPs). These participants carried out auditory-perceptual judgment of 60 dysphonic voice samples under two counterbalanced experimental conditions (with and without anchor voices). Each of the three groups was randomly divided into two subgroups to balance the experimental conditions. Interrater reliability for each subgroup was calculated using Krippendorff's α and 95% confidence intervals. For all the groups involved in the study, interrater reliability was higher when anchor voices aided perceptual judgment for most parameters of the GRBAS scale. For the different parameters of GRBAS, interrater reliability for the UG group varied from fair (20 < α ≤ 40) to moderate (40 < α ≤ 60). In contrast, it was fair (20<α≤ 40) to substantial (60 <α≤ 80) for the PG group and moderate (40 <α≤ 60) to substantial (60 <α ≤ 80) for the SLP group. Variations in reliability were the least for the SLP group compared to the UG and PG groups. However, there were overlaps in interrater reliability between the groups, as revealed by the 95% confidence intervals. Anchor voices help improve the auditory-perceptual judgment of voice quality, especially interrater reliability. Listener expertise is also shown to influence the interrater reliability of auditory-perceptual judgment of voice quality.