PROJECT SUMMARY/ABSTRACT COCHLEAR MECHANICS, WAVE PROPAGATION, AND COMPRESSION The proposed project continues a program of research that is improving our knowledge of cochlear function through a combination of theoretical and empirical studies of fundamental processes in the peripheral auditory system that have both basic and translational implications. The first aim addresses a theoretical issue concerning power amplification in cochlear mechanics. It posits a mechanism for amplification in a four- chamber cochlear model and investigates consistency with experimental observations. This aim tests supporting evidence for the existence of a hypothetical cochlear amplifier. The second aim focuses on further development of a method for measurement of acoustic emissions from the inner ear that are evoked by wide- band noise stimuli. Signal processing and statistical analysis of these cochlear-reflectance measurements will improve their sensitivity to hearing loss and improve the accuracy of their prediction of hearing threshold. The remaining two aims of this project both utilize a cochlear-processing simulation, which is based on an existing nonlinear model of cochlear mechanics. Through a combination of computational modeling and behavioral measurements these aims will investigate two perceptual phenomena: consonant recognition and loudness growth. These aims will both test the hypothesis that cochlear processing produces spectro-temporal features that are closer to observed perception than features derived directly from the acoustic signal. Through efforts related to all four aims, questions that possess both basic scientific interest and applied clinical relevance will be addressed by combined application of measurement and modeling efforts.