A model of the cochlear apex and structure for study of mechanism and response characteristics

Abstract

We provide a model of the cochlear apex that is geared towards studying: cochlear function represented by common response characteristics (e.g., sharpness of tuning), governing mechanisms, inter-relations between the response characteristics, inter-relations between the traveling wave and point admittance effective mechanics, and the relationship between response characteristics and mechanism. The model currently used for some of these ends is an uncoupled resonant simple harmonic oscillator. However, this framework is inconsistent with current knowledge in the field. Hence, an alternative framework must be provided for these purposes. To these ends, in this paper, we construct a general parametric model of the cochlear that represents the Organ of Corti as a single partition in a box fluid model. The model provides closed-form expressions for responses—specifically membrane velocity and fluid pressure—and the corresponding response characteristics. Development of the model includes construction of effective mechanics, construction of responses and their characteristics, and validation. We find that our model provides a suitable representation of data, by using auditory nerve fiber Wiener-Kernel data to approximate mechanical responses. Also, we show that the model may be extrapolated beyond its primary purposes for use as a computationally efficient cochlear front-end to auditory aid devices and speech processing programs.