Accuracy and cut-off values of different acoustic measures in the sustained vowel task of Brazilian Portuguese speakers.

Abstract

Purpose: To define cut-off values for acoustic measures extracted from the sustained vowel [a] task to discriminate between the presence and absence of vocal disorders in Brazilian Portuguese speakers.

Methods: The sample consisted of 376 participants, 288 female and 88 male, with a mean age of 41.20 ± 14.04 years. All individuals underwent a laryngological evaluation and a voice recording session, during which a sustained vowel [a] sample was collected. Subsequently both auditory-perceptual and acoustic analyses of the voice were performed. Among the participants 277 were classified as having a vocal disorder and 99 as having no vocal disorder. A total of 44 acoustic measures were extracted and analyzed using ROC curves to determine the cut-off value for each measure, along with their performance metrics (sensitivity, specificity and AUC).

Results: Cut-off values were established for 23 of the 44 extracted acoustic measures. Six measures showed robust and clinically relevant performance in discriminating between voices with and without vocal disorders in Brazilian Portuguese speakers. The measures with AUC values greater than 0.70 and balanced sensitivity and specificity above 70% were: Amplitude Variability Index (AVI) (≤0,91), Glottal-to-noise excitation (GNE)2000Hz (>0,92), Spectral Noise Level (SNL)100-2600Hz (≤7,71), SNL100-3000Hz (≤3,38), SNL100-8000Hz (≤10,95) and SNL5100-8000Hz (≤-1,84).

Conclusion: Six acoustic measures demonstrated satisfactory performance in identifying the presence of vocal disorders in Brazilian Portuguese speakers. Ten measures showed good performance for voice screening purposes and seven for diagnostic confirmation of vocal disorders.