Validation of the Acoustic Voice Quality Index, Version 03.01, to the Brazilian Portuguese Language

Introduction. Multiparametric indexes provide a more robust acoustic analysis of voice quality considering more than one acoustic parameter in the evaluation of sustained phonation and continuous speech. However, once the continuous speech is considered, differences among languages must be addressed. Objective. To assess the concurrent validity and the diagnostic accuracy of the Acoustic Voice Quality Index version 03.01 (AVQI 03.01) in the Brazilian Portuguese. Method. The counting numbers 1-20 and the vowel /a/ of 150 subjects were used (37 nondysphonic; 113 with dysphonia). To reach higher precision of the AVQI, the length of the voiced parts of the continuous speech and the sustained vowel were equalized. Nine voice specialists performed the perceptual auditory judgment of the samples. However, only five listeners were chosen for further analysis based on their moderate to substantial intrarater reliability (Cohen's Kappa: 0.605-0.773) and their reasonable inter-rater reliability (Fleiss Kappa: 0.429). The index concurrent validity and diagnosis accuracy were analyzed with the Spearman correlation and the receiver-operating characteristic curve. Results. The AVQI 03.01 concurrent validity was high (r = 0.716). The coefficient of determination demonstrated that 51% of the vocal deviation can be explained by the acoustic analysis (r(2) = 0.512). The diagnostic accuracy was excellent (90.4%). At a threshold of 1.33, the AVQI sensitivity and specificity were 78.8% and 90.6%, respectively. Conclusion. The AVQI is a valid tool in the Brazilian Portuguese language. It can be used as a screening tool, for clinical follow-up and evaluation preand post-treatment/procedures. Voice specialist should be aware of false-negative and false-positive results of the AVQI, especially for screening purposes.