Abstract
It has been hypothesized that the otoacoustic emissions (OAEs) are generated at least by two fundamental mechanisms; the nonlinear distortion and linear reflection within the cochlea. The recent studies show that different components of the organ of Corti (OoC) vibrate unsynchronized both in phase and magnitude. The difference is dramatically frequency dependent. We have developed and validated a finite-element model of the mouse cochlea against two sets of measurement at the cochlear base and apex. The nonlinear distortion and linear reflections have been implemented in the model- the former one by the active outer hair cells (OHCs) and the later one by introducing the impedance irregularity in the baseline model components (e.g., stiffness, mass and geometrical parameters). To differentiate the contribution of different components of OoC on the total OAE response, the baseline parameters of the model has been adjusted to vary vibration magnitudes of those components. The preliminary results show that the impedance irregularities generate the phase decay of the stimulus-frequency OAEs more than the nonlinear distortion (e.g., 1-2 cycles per 1kHz with 10% random perturbations of Young’s modulus of the basilar membrane), consistent with data in the literature. The perturbations of other model parameters are under investigation.