Frequency Characteristics of Fast and Slow Waves in the Cochlea: A Finite Element Analysis

The aim of this study was to predict the characteristics of two types of cochlear pressure waves, so-called fast and slow waves, which are generated by vibration of the stapes. A two-dimensional finite-element model of the organ of Corti, including the fluid-structure interaction with the surrounding lymph fluid, was constructed. Using this model, the magnitude and phase of the fast and slow waves were predicted so as to match the numerically obtained pressure distribution in the scala tympani with that of the intracochlear pressure measurement [1]. As a result, it was found that the magnitude of the fast wave increases as a function of frequency, and that of the slow wave grows gradually to the point of resonance (characteristic frequency: CF) with increasing frequency, then falls sharply.