While several acoustic measures have been proposed to quantify listener ratings of breathy voice quality, most have failed to give a consistent and high correlation with perceptual ratings of breathiness. One reason for these limitations is that most acoustic measures do not address the nonlinear processes that occur in the peripheral auditory system during the auditory perceptual process. It was hypothesized that modeling such nonlinear events during signal processing may provide objective parameters that better correspond to perceptual ratings of breathy voice quality. Ten listeners rated 27 voice stimuli using a five-point rating scale. Acoustic measures were determined from these stimuli and were selected based on their history of having a moderate to strong correlation to perceptual ratings of breathiness. The stimuli were also analyzed using an auditory model proposed by Moore, Glasberg, and Baer [J. Audio Eng. Soc. 45(4), 224-239 (1997)], and new measures were calculated from the output of this model. These measures included the partial loudness of the signal and the loudness of the aspiration noise. Measures obtained from the output of the auditory model were found to account for a high amount of variance in the perceptual ratings of breathiness.