Evoked otoacoustic emissions in a nonlinear model of the cochlea.

A nonlinear, transmission-line-analog model of the ear is presented for the purpose of simulating the experimental data of delayed evoked otoacoustic emissions (DEOAEs). The model produces echoes very similar to DEOAEs in the latency, saturation and spectral features when hypothetical, highly damped points arranged on the BM with an equal spacing are assumed. Special attention is payed to the reason for the long latency of DEOAEs. In the model, the delay occurs spuriously by cancellation of components scattered from the irregular points and is longer than the simple round trip time of the travelling wave from the stapes to the place of characteristic frequency. The echoes in the model are basically linear for the low intensity stimuli and only when the stimuli surpass a certain level they saturate owing to the nonlinearity of the BM damping.