Validation of the Acoustic Voice Quality Index in the Lithuanian Language

Abstract

Objectives: The aim of the present study was to validate the Acoustic Voice Quality Index in Lithuanian language (AVQI-LT) and investigate the feasibility and robustness of its diagnostic accuracy, differentiating normal and dysphonic voice.

Methods: A total of 184 native Lithuanian subjects with normal voices (n = 46) and with various voice disorders (n = 138) were asked to read aloud the Lithuanian text and to sustain the vowel /a/. A sentence with 13 syllables and a 3-second midvowel portion of the sustained vowel were edited. Both speech tasks were concatenated, and perceptually rated for dysphonia severity by five voice clinicians. They rated the Grade (G) from the Grade Roughness Breathiness Asthenia Strain (GRBAS) protocol and the overall severity from the Consensus Auditory-perceptual Evaluation of Voice protocol with a visual analog scale (VAS). The average scores (G_mean and VAS_mean) were taken as the perceptual dysphonia severity level for every voice sample. All concatenated voice samples were acoustically analyzed to receive an AVQI-LT score.

Results: Both auditory-perceptual judgment procedures showed sufficient strength of agreement between five raters. The results achieved significant and marked concurrent validity between both auditory-perceptual judgment procedures and AVQI-LT. The diagnostic accuracy of AVQI-LT showed for both auditory-perceptual judgment procedures comparable results with two different AVQI-LT thresholds. The AVQI-LT threshold of 2.97 for the G_mean rating obtained reasonable sensitivity = 0.838 and excellent specificity = 0.937. For the VAS rating, an AVQI-LT threshold of 3.48 was determined with sensitivity = 0.840 and specificity = 0.922.

Conclusions: The AVQI-LT is considered a valid and reliable tool for assessing the dysphonia severity level in Lithuanian-speaking population.

Keywords: Acoustic Voice Quality Index; Acoustic voice analysis; Dysphonia; Lithuanian language; Voice assessment.