Spectral-cepstral estimation of dysphonia severity: external validation.

Objective: The current study applied an acoustic algorithm incorporating measures from cepstral and spectral analyses, the Cepstral Spectral Index of Dysphonia (CSID), in an attempt to externally validate the CSID as an acoustic estimate of dysphonia severity.

Methods: Correlation (Pearson's r) between the CSID and trained listener-perceived severities as rated on the Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) was calculated from sentence and sustained vowel samples from 56 patients before or after they underwent thyroid surgery.

Results: A strong correlation was identified between the mean CSID values calculated across CAPE-V sentences and vowels and the median rating of perceived overall severity (r = 0.82; p < 0.001). The CSID values did not differ significantly from their corresponding auditory-perceptual ratings of dysphonia severity for these samples (CSID: mean, 15.54, SD, 16.63; CAPE-V Severity: mean, 17.33, SD, 13.61; p = 0.16).

Conclusions: Independent testing of an acoustic algorithm incorporating measures from cepstral and spectral analyses (the CSID) confirmed a strong correlation of the CSID to perceptual ratings of overall voice quality. This study provides external validation of the CSID as a robust correlate of dysphonia severity as rated by trained listeners.