Fritze W, Köhler W
Laryngol Rhinol Otol (Stuttg). 1986 Nov;65(11):600-3.
In contrast to the formerly held opinion it is now clear that the spontaneous oto-acoustic emissions (OAEs) are pure sinus tones. Frequency shifting (small oscillations and a drifting in one of the two directions) causes broadening of the image in Fourier's transformation, especially when being averaged. These spontaneous OAEs can be observed in ears with minimal disturbance--often not yet detectable by means of pure tone threshold. In such ears the synchronisation of the hair-cells is out of order and this leads to the spontaneous OAEs. With increasing sensitivity of the microphones OAEs can be found in more and more ears. A connection between spontaneous and evoked OAEs can be shown when calculating a FFT from the image of an evoked emission: the spectrum is similar to that of spontaneous OAEs from the same ear. TTS situations in spontaneous OAEs: the reduction of the ability of synchronisation cancels the emission, which will reappear after some time (shifted in frequency). To explain the frequency resolution in the cochlea an active filter has been postulated and the OAEs are claimed to be a reflection of the same; in fact, they are one of the proverbial keyholes through which we might gain a glimpse of what is taking place in the cochlea.
与以前的观点相反，现在已经清楚的是，自发性耳声发射（OAEs）是纯正弦音调。频率偏移（小振荡和向两个方向之一的漂移）会导致傅里叶变换中的图像变宽，尤其是在平均时。这些自发性耳声发射可以在干扰最小的耳朵中观察到——通常纯音阈值还检测不到。在这样的耳朵中，毛细胞的同步出现紊乱，这导致了自发性耳声发射。随着麦克风灵敏度的提高，越来越多的耳朵中可以检测到耳声发射。当从诱发发射的图像计算快速傅里叶变换（FFT）时，可以显示出自发性耳声发射和诱发耳声发射之间的联系：频谱与同一只耳朵的自发性耳声发射频谱相似。自发性耳声发射中的暂时性阈移（TTS）情况：同步能力的降低会使发射消失，一段时间后（频率发生偏移）又会重新出现。为了解释耳蜗中的频率分辨率，人们假定了一个有源滤波器，并且声称耳声发射是其反映；事实上，它们是众所周知的关键窗口之一，通过它们我们可能会瞥见耳蜗中正在发生的事情。
