Abstract
The FFT analysis of spontaneous otoacoustic emissions (s-OAEs) and evoked otoacoustic emissions (e-OAEs) were studied in 12 ears of 6 normal hearing subjects. The s-OAEs were recognized in 4 ears, and the frequencies of s-OAEs were almost corresponded with the frequencies at which the e-OAE could be recorded most apparently. And also, the e-OAEs in these 4 ears were continual. The results of the analyses of the e-OAE sound pressure curve under the same stimulus sound pressure level indicated that the e-OAEs tend to appear at the frequencies of s-OAEs. And also, the comparison between expected e-OAE power spectrums and actually measured power spectrums, and the FFT analysis of e-OAE showed the same result. From the results of averaging data along the time axisunder no stimulus sound, the phase of s-OAE could not be synchronized under this e-OAE recording conditions. When the phase of the stimulus sound was changed, e-OAEs at the frecuencies of s-OAEs also appeared as the phase follwing responses. Therefore, in the ears with s-OAE, the s-OAE might be synchronized with the stimulus sound as the trigger, and as a result, e-OAE was recorded to be continual.
