An Assessment of Different Praat Versions for Acoustic Measures Analyzed Automatically by VoiceEvalU8 and Manually by Two Raters.

INTRODUCTION

The purpose of the study was to assess acoustic measures of fundamental frequency (f), standard deviation of f (SD of f), jitter%, shimmer%, noise-to-harmonic ratio (NHR), smoothed cepstral peak prominence (CPPS), and acoustic voice quality index analyzed through multiple Praat versions automatically by VoiceEvalU8 or manually by two raters. In addition, default settings to calculate CPPS in two Praat versions manually analyzed by two raters were compared to Maryn and Weenik procedures for CPPS automatically analyzed by VoiceEvalU8.

METHODS

Nineteen vocally healthy females used VoiceEvalU8 to record three 5-s sustained /a/ trials, the all voiced phrase "we were away a year ago," and a 15-s speech sample twice a day for five consecutive days. Two raters manually completed acoustic analysis using different versions of Praat and compared that analysis to measures automatically generated through a version of Praat used by VoiceEvalU8. One-way analyses of variance were run for all acoustic measures with post-hoc testing by the Bonferroni method. For acoustic measures that demonstrated significant differences, intraclass correlation coefficients were conducted.

RESULTS

Results showed no significant differences across automatic and manual analysis for different versions of Praat for all acoustic measures during /a/, for f, jitter%, shimmer%, and NHR during the phrase, for jitter%, shimmer%, NHR, and CPPS during speech, and for acoustic voice quality index calculated from both sustained /a/ and the phrase. The default Praat settings for CPPS were not significantly different from the Maryn and Weenik procedures for sustained /a/ and speech. Significant differences were present for SD of f and CPPS during the phrase and f and SD of f during speech. SD of f and CPPS in the phrase were moderately correlated and f and SD of f during speech demonstrated good to excellent correlations across the different versions of Praat.

CONCLUSIONS

Acoustic measures analyzed through sustained /a/ and some of the acoustic measures during the phrase and speech were not different across multiple versions of Praat. Automatic analysis by VoiceEvalU8 produced similar mean values as compared to manual analysis by two raters. Even though SD of f and CPPS in the phrase and f and SD of f in speech were different across the versions of Praat, the measures demonstrated moderate to excellent reliability.