Estimation of active cochlear nonlinearity by multi-component distortion-product otoacoustic emissions

摘要

Multi-component distortion-product otoacoustic emissions (DPOAEs) are generated by the nonlinear mechanism of cochlear activity. Recent research on DPOAEs tends to neglect all but the 2f(1) - f(2) distortion component leading to a very narrow view of the activity, although the other components may prove to have supplementary value [1, 2, 3]. In fact, the pattern of such multi-component DPOAEs indicates a great deal about cochlear nonlinearity. This paper will demonstrate our approach to estimate the input-output function of the cochlear nonlinearity by the multi-component DPOAEs via introducing generating models of the multi-component DPOAEs. The cochlear nonlinearity for generating multi-component DPOAEs can be modelled by a polynomial power series model and a compressive hyperbolic model. Then the input-output function of the cochlear nonlinearity can be calculated from the multi-component DPOAEs. This input-output function represents the cochlear nonlinearity and will give the same pattern of multi-component DPOAEs as recorded from subjects. The results suggest that the generating mechanism of the multi-component DPOAEs is level dependent in such a way that, at lower stimulus level, an active cochlear nonlinearity modelled by polynomial power series dominates the generation of the multi-component DPOAEs, it is the compressive hyperbolic model plays role for the cochlear nonlinearity at middle stimulus level, and a linear process is involved at the higher stimulus level. [References: 24]