Cepstral Acoustic Measurements: Influence of Speech Task and Degree of Vocal Deviation.

Objective: To analyze whether there are differences in the cepstral measures obtained in different speech tasks, depending on the presence and degree of vocal deviation, and to analyze if there is a correlation between the cepstral measures obtained from different speech tasks and the general degree of vocal deviation.

Method: Analysis of 258 vocal samples of the sustained vowel [a] and connected speech (counting numbers) from a database, including 160 dysphonic and 98 nondysphonic voices. The counting number samples were edited in three different durations: counting from 1 to 10, from 1 to 11, and from 1 to 20. Five speech-language pathologists (SLPs), voice specialists, carried out the perceptual-auditory judgment of the overall degree of vocal deviation (ODD) using the G from the overall dysphonia grade, roughness, breathiness, asthenia, and strain (GRBAS) scale. We extracted the cepstral peak prominence (CPP) and smoothed cepstral peak prominence (CPPS) measurements from all the vocal samples using an extraction script in the free software Praat.

Results: CPP and CPPS were different between dysphonic and nondysphonic individuals, regardless of the speech task, with lower values for dysphonic. Also, CPP values between the vowel and the connected speech tasks were different between both groups. Only the CPPS showed differences between all the speech tasks depending on the degree of vocal deviation. There was a strong negative correlation between the CPPS, CPPS, CPPS, CPPS and the ODD, and a moderate negative correlation between CPP, CPP, CPP, CPP, and ODD.

Conclusions: There are differences in the cepstral measures obtained in different speech tasks, depending on the presence of dysphonia and ODD. CPP and CPPS values are different between dysphonic and nondysphonic individuals in all speech tasks. There is a moderate negative correlation between CCP in the different speech tasks and ODD, while there is a strong negative correlation between CPPS in the different speech tasks and ODD.