Department of Psychology and Center for Perceptual Systems, 1 University Station A8000, University of Texas, Austin, Texas 78712-0187, USA.
J Acoust Soc Am. 2010 Feb;127(2):955-69. doi: 10.1121/1.3279832.
A procedure for extracting the nonlinear component of the stimulus-frequency otoacoustic emission (SFOAE) is described. This nSFOAE measures the amount by which the cochlear response deviates from linear additivity when the input stimulus is doubled in amplitude. When a 4.0-kHz tone was presented alone, the magnitude of the nSFOAE response remained essentially constant throughout the 400-ms duration of the tone; response magnitude did increase monotonically with increasing tone level. When a wideband noise was presented alone, nSFOAE magnitude increased over the initial 100- to 200-ms portion of the 400-ms duration of the noise. When the tone and the wideband noise were presented simultaneously, nSFOAE magnitude decreased momentarily, then increased substantially for about the first 100 ms and then remained strong for the remainder of the presentation. Manipulations of the noise bandwidth revealed that the low-frequency components were primarily responsible for this rising, dynamic response; no rising segment was seen with bandpass or highpass noise. The rising, dynamic nSFOAE response is likely attributable to activation of the medial olivocochlear efferent system. This perstimulatory emission appears to have the potential to provide information about the earliest stages of auditory processing for stimuli commonly used in psychoacoustical tasks.
描述了一种提取刺激频率耳声发射（SFOAE）非线性分量的方法。nSFOAE 测量了当输入刺激的幅度增加一倍时，耳蜗反应偏离线性加性的程度。当单独呈现 4.0 kHz 纯音时，nSFOAE 响应的幅度在整个纯音持续时间的 400 ms 内基本保持不变；响应幅度随声级的增加而单调增加。当单独呈现宽带噪声时，nSFOAE 的幅度在噪声持续时间的最初 100-200 ms 内增加。当纯音和宽带噪声同时呈现时，nSFOAE 的幅度会暂时下降，然后在前 100 ms 左右显著增加，然后在呈现的其余部分保持较强。噪声带宽的操纵表明，低频成分主要负责这种上升的动态响应；带通或高通噪声没有观察到上升段。上升的动态 nSFOAE 响应可能归因于中橄榄耳蜗传出系统的激活。这种刺激前发射似乎有可能为在心理声学任务中常用的刺激提供有关听觉处理早期阶段的信息。
