Validity of the Cepstral Spectral Index of Dysphoin the Persian Language in Sustained Vowel, Sentence, and All-Voiced Sentence Contexts Publisher Pubmed



Saeedi S ; Awan S N ; Aghadoost S ; Watts C R ; Aghajanzadeh M ; Latoszek B B V
Source: Journal of Speech, Language, and Hearing Research Published:2026

Abstract

Purpose: Cepstral Spectral Index of Dysphonia (CSID) characterizes andobjec-tively quantifies characteristics of voice quality. The findings of CSID’s impact idetermining dysphonia characteristics in different languages, however, are unclear but important if this tool is to be used cross-linguistically. Therefore, tpurpose of the study was to determine the validity of CSID in Persian speakeMethod: Persian-speaking participants were assigned to two groups: patients with voice disorders (n = 102) and vocally healthy speakers (n = 38). They duced a sustained vowel /ɑ/ and a Persian connected speech sample reprsenting a sentence with a majority of voiced sounds. Three speech-languagpathologists conducted auditory-perceptual ratings on a 4-point ordinal scale (vocally healthy, mild, moderate, or severe). Acoustic analysis was conducteusing the Analysis of Dysphonia in Speech and Voice software. CSID values addition to cepstral peak prominence (CPP), CPP standard deviation, low-to-high (L/H) spectral ratio, and L/H spectral ratio standard deviation weextracted from (a) a 1-s segment of the middle part of the sustained vowel, the onset to offset of the connected speech sample, and (c) the same sentefurther trimmed to contain only voiced parts by omitting voiceless sections. Results: The area under the curve (AUC) values for the three tasks were as lows: sustained vowel, AUC = 0.978; connected speech sentence, AUC 0.961; and all-voiced connected speech sentence, AUC = 0.957. The cutopoints of 4.88 (a sensitivity of 92.2% and a specificity of 94.7%), −4.14 (a setivity of 91.2% and a specificity of 92.1%), and 6.76 (a sensitivity of 83.3% a specificity of 97.4%) yielded the highest level of diagnostic findings for CSin sustained vowel, connected speech sentence, and all-voiced connected speech sentence, respectively. In addition, significant and strong correlations were found between the CSID values and dysphonia category in the sustainvowel (r = .815, p < .001), connected speech sentence (r = .841, p < .001), all-voiced connected speech sentence (r = .833, p < .001). Conclusion: The findings of this studyshowed that CSID is a valid acoustics-based index with the potential to assist clinicians in achieving a more complcharacterization and quantification of dysphonia in Persian-speaking clients during voice assessments. © 2026 American Speech-Language-Hearing Association.