Validation of Acoustic Breathiness Index (ABI) in the South Indian Population.

BACKGROUND

Acoustic Breathiness Index (ABI) is an acoustic model which equates to the auditory-perceptual (A-P) measure of breathiness. Globally, ABI has been validated in multiple languages. To date, empirical studies validating ABI in the South Indian population have not been carried out. Moreover, there is only minimal evidence on the impact of language and gender on ABI.

OBJECTIVES

This study attempted to validate ABI in languages of Malayalam and Kannada with "B" and "G" of GRBAS. The authors also examined the influence of language and gender on ABI.

METHODS

The authors retrospectively analyzed a dataset consisting of 160 voice samples (91 normophonic and 69 dysphonic). Five speech-language pathologists perceptually evaluated these samples on the GRBAS scale. PRAAT software was used to calculate ABI for each voice sample. The authors also determined the effects of language and gender on ABI. Following this, ABI's concurrent validity and diagnostic accuracy were examined relating to "B" and "G" of the GRBAS scale.

RESULTS

The judges reached a moderate agreement on the perceptual evaluation of voice quality. The authors observed neither language nor gender differences in ABI. The concurrent validity of ABI was strong (r = 0.761) when correlated against "B". Further, evaluations revealed that an ABI value of >3.66 could distinguish between breathy and non-breathy voice samples with an area under the curve of 0.816 (Sensitivity = 61.73%; Specificity = 94.93%). On the other hand, the concurrent validity of ABI in correlation with "G" did not yield the optimal result.

CONCLUSIONS

ABI is a valid acoustic tool for identifying breathiness in the languages of Malayalam and Kannada. ABI correlates better with "B" than "G" on the GRBAS scale. ABI is independent of language and gender.