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.