Validation of the acoustic breathiness index to the Brazilian Portuguese language

Objective: To assess the concurrent validity and the diagnostic accuracy of the Acoustic Breathiness Index (ABI) in Brazilian Portuguese. Methods: The counting numbers 1-20 and the vowel /a/ of 150 subjects were recorded (37 vocally healthy and 113 with dysphonia). The analyzed samples were the counting number 1-11 and 3 s of the sustained vowel. Nine voice specialists performed the perceptual judgment of the degree of breathiness. The Spearman Correlation and the receiver operating characteristic (ROC) curve were used to assess ABI's concurrent validity and diagnosis accuracy. Results: Results from five listeners were chosen for the study analyses due to moderate and substantial intra-rater reliability (Cohen's Kappa values = 0.520-0.772) and moderate inter-rater reliability (Fleiss Kappa = 0.353). The ABI presented a high concurrent validity (r = 0.746); 55.6% of the breathiness vocal deviation can be explained by the acoustic analysis (r(2) = 0.556). The ROC curve presented good diagnostic accuracy (85.2%). At a threshold of 2.94, the sensitivity was 75.3% and the specificity was 93.4%. Conclusion: The ABI is a valid tool for screening and patient's follow-up regarding breathy vocal qualities in the Brazilian Portuguese language.