Noise-evoked otoacoustic emissions in humans.

Click-evoked otoacoustic emissions (CEOAEs) and acoustical responses evoked by bandlimited Gaussian noise (noise-evoked otoacoustic emissions; NEOAEs) were measured in three normal-hearing subjects. For the NEOAEs the first- and second-order Wiener kernel and polynomial correlation functions up to the sixth order were calculated by cross correlating the noise stimulus and the emission response. Emission components were only found in the first-order Wiener kernel. These kernels were dependent on the stimulus level, indicative of the nonlinear response of the cochlea. For each subject the frequency contents of the CEOAE and the first-order Wiener kernel were nearly identical. In the second-order Wiener kernels and higher-order polynomial correlation functions no significant contributions were identified. Apparently, odd and even order nonlinearities cannot be detected by Wiener kernel analysis.