Acoustic measures of dysphonic severity across and within voice types.

The purpose of the study was to explore an interaction between pathologic voice type and the acoustic prediction of dysphonic severity. One hundred and two phonatory samples, representing a wide range of laryngeal conditions, were categorized by listeners into three voice types: breathy, rough, and hoarse. A second group of trained listeners rated the severity of the samples on a 7-point scale. Twenty-five frequency- and time-domain measures were used to predict perceptual severity. Multiple regression analyses showed that the most useful measure for the prediction of severity across voice types was noise-to-harmonic ratio (NHR). The severity of individual voice types was predicted with differential results on the basis of both short- and long-term measures of perturbation.