A Computer-Based Tool for the Assessment of Voice Quality Through Visual Analogue Scales: VAS-Simplified Vocal Profile Analysis

In this study we propose a new tool for the perceptual assessment of voice quality. For its design, we have adapted the Simplified Vocal Profile Analysis so that the new tool features two main characteristics: (1) the ordinal scalar degrees of the original protocol are turned into a visual analog scale; and (2) the original paper-based version of the protocol is now a computer-based implementation. In order to assess the reliability of the new tool, five phoneticians listened to 12 different speakers and evaluated their voice quality using the proposed tool. Inter-rater agreement was then calculated using the Intraclass Correlation Coefficient. The results show that high agreement was reached for most of the perceptual settings of the protocol. Yet more investigations seem necessary into the continuous nature of the perceptual dimensions making up the voice quality of a speaker. As a preliminary approach to the graphical possibilities that the visual analog scale offers to the Simplified Vocal Profile Analysis, we explore the usefulness of multiple dot plots and propose an adaptation of the Bland-Altman plot to be used in pairwise comparisons. In this study, these visualization techniques are tested on two pairs of identical twins.