Simulation of short-pulse DPOAEs using a hydrodynamic time-domain cochlea model: The effect of interchanging the elicitors Free

Distortion-product otoacoustic emissions (DPOAEs) are used in clinics and research to noninvasively ascertain the functional state of the cochlea. According to a widely accepted model, the cubic distortion product at 2f₁ - f₂ consists of a nonlinear-distortion component, which is generated in the overlap region of the two primary tones, and a coherent-reflection component arising at the tonotopic place of the distortion-product frequency. Pulsing the f₂ primary in the presence of a f₁ tone enables the separation of the two DPOAE components in time-domain recordings due to their different latencies. However, short-pulse DPOAE responses show larger amplitudes and shorter latencies when interchanging the temporal arrangement of the primary tones, i.e. triggering DPOAE generation with a f₁ short pulse in the presence of a f₂ tone. The present work utilizes a one-dimensional implementation of a nonlinear hydrodynamic cochlea model for the human cochlea to simulate cochlear distortion products for the two short-pulse acquisition paradigms. Matrix formulation of the equations of motion was used to compute the solution directly in the time domain. The properties of the simulated cochlear distortion products closely match experimental data from normal-hearing subjects. The results suggest that the temporal arrangement of the primary tones has a distinct influence on the mechanoelectrical transduction near the f₂ place which is reflected by changes in the DPOAE responses.