J Voice. 2015;Epub ahead of print.
The purpose of this study was to explore the criterion-related concurrent validity of two standardized auditory-perceptual rating protocols and the Acoustic Voice Quality Index (AVQI) for measuring dysphonia severity in Korean speech.
Sixty native Korean subjects with various voice disorders were asked to sustain the vowel [a:] and to read aloud the Korean text "Walk." A 3-second midvowel portion of the sustained vowel and two sentences (with 25 syllables) were edited, concatenated, and analyzed according to methods described elsewhere. From 56 participants, both continuous speech and sustained vowel recordings had sufficiently high signal-to-noise ratios (35.5 dB and 37 dB on average, respectively) and were therefore subjected to further dysphonia severity analysis with (1) "G" or Grade from the GRBAS protocol, (2) "OS" or Overall Severity from the Consensus Auditory-Perceptual Evaluation of Voice protocol, and (3) AVQI.
First, high correlations were found between G and OS (rS = 0.955 for sustained vowels; rS = 0.965 for continuous speech). Second, the AVQI showed a strong correlation with G (rS = 0.911) as well as OS (rP = 0.924). These findings are in agreement with similar studies dealing with continuous speech in other languages.
The present study highlights the criterion-related concurrent validity of these methods in Korean speech. Furthermore, it supports the cross-linguistic robustness of the AVQI as a valid and objective marker of overall dysphonia severity.