Cochlear mechanics with fluid viscosity and compressibility.

Abstract

We extend the one-dimensional cochlear model to include the effect of viscosity and compressibility of the cochlear fluid. The resulting boundary-value problem is solved exactly using numerical techniques and semianalytically using the WKB approximation. Our results indicate the general trend of basilar membrane response increasing with an increase in compressibility or a decrease in viscosity. However, in the physiologically relevant range of these parameters, the change in the response is insignificant, justifying the assumption made in one-dimensional cochlear models that these effects are unimportant. Using the semianalytical WKB algorithm, we also demonstrate the simultaneous existence of forward- and backward-traveling waves on the basilar membrane.