Quantitative measure of multicomponents of otoacoustic emissions.

A method for quantitatively measuring measuring multicomponents of otoacoustic emissions (OAE) was developed in this study. The method is based on the rationale that, if the acoustic emission is a vector sum of multicomponents coming from different locations in the cochlea, each component will show a delay. The proposed method consists of the following steps: (1) the amplitude and phase of the emission is measured when the emission frequency is swept; (2) the real part of the spectrum is obtained based on the amplitude and phase spectra; and (3) the real part of the emission spectrum is then analyzed using a Fourier transform to extract the multiple components. The theoretical basis and practical procedure of this method are described, and in vitro and in vivo tests are used to demonstrate the validity of the method. Preliminary data demonstrate the multicomponents of the extracochlear electrically evoked otoacoustic emission (EEOAE).