Effect of Voiced Segment Extraction on Voice of Vocal Cord Paralysis: Focused on Cepstral Analysis

Abstract

Background and Objectives The purpose of this study was to investigate the effect of unvoiced segments on the cepstral analysis in patients with vocal cord paralysis (VCP).Subjects and Method A total 302 subjects (173 subjects with VCP and 129 normal voice subjects) participated in this study. The sustained vowel /a/ 2 seconds and one sentence of ‘Sanchaek’ were edited, and analyzed by Praat script. The cepstral analyses were performed using sustained vowel (SV), continuous speech (CS), and extracted continuous speech (EXT) samples. The auditory-perceptual (AP) rating was also completed by three raters.Results First, there were significant differences in all variables except low-to high spectral ratio(L/H ratio)_EXT between two groups. Second, cepstral peak prominence (CPP), smoothed cepstral peak prominence (CPPS), and L/H ratio showed significant differences in SV, CS, and EXT samples. Third, cepstral measurements were highly correlated with the AP ratings. Finally, the level of discrimination of dysphonia estimated from CPP and CPPS gotten from SV and CS values was more than area under the curve (AUC) of 0.941. AUC of 0.880 or more was also found in EXT.Conclusion In this study, we confirmed that both CS and EXT are highly predictive of pathologic speeches. Further study will also need to be validated for a more diverse group of voice disorders.