A meta-analysis : acoustic measurement of roughness and breathiness

Purpose Over the last 5 decades, many acoustic measures have been created to measure roughness and breathiness. The aim of this study is to present a meta-analysis of correlation coefficients ( r ) between auditory-perceptual judgment of roughness and breathiness and various acoustic measures in both sustained vowels and continuous speech. Method Scientific literature reporting perceptual–acoustic correlations on roughness and breathiness were sought in 28 databases. Weighted average correlation coefficients ( r w ) were calculated when multiple r -values were available for a specific acoustic marker. An r w ≥ .60 was the threshold for an acoustic measure to be considered acceptable. Results From 103 studies of roughness and 107 studies of breathiness that were investigated, only 33 studies and 34 studies, respectively, met the inclusion criteria of the meta-analysis on sustained vowels. Eighty-six acoustic measures were identified for roughness and 85 acoustic measures for breathiness on sustained vowels, in which 43 and 39 measures, respectively, yielded multiple r -values. Finally, only 14 measures for roughness and 12 measures for breathiness produced r w ≥ .60. On continuous speech, 4 measures for roughness and 21 measures for breathiness were identified, yielding 3 and 6 measures, respectively, with multiple r -values in which only 1 and 2, respectively, had r w ≥ .60. Conclusion This meta-analysis showed that only a few acoustic parameters were determined as the best estimators for roughness and breathiness.