Indications of different distortion product otoacoustic emission mechanisms from a detailed f1,f2 area study
Indications of different distortion product otoacoustic emission mechanisms from a detailed f1,f2 area study
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DOI：
10.1121/1.428351
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发表时间：
2000-01-01
影响因子：
2.4
通讯作者：
Kemp, DT
中科院分区：
文献类型：
--
作者：
Knight, RD;Kemp, DT
基底膜上2f(1)-f(2)失真积（DP）的主要产生位点通常被认为是在高频刺激音峰值附近。这个位置也被证明是耳道内DP耳声发射（DPOAE）的一个来源，但已知在DP频率位置区域存在第二个发射源。DPOAE相位与频率梯度提供了一种研究发射机制的方法。根据2f(1)-f(2) DPOAE是由小的刺激频率比还是大的刺激频率比引起，已经提出了“波固定”和“位置固定”机制来解释非常不同的相位梯度。DPOAE相位与频率梯度可以通过扫描f(1),f(2)或通过扫描两个频率保持恒定的频率比来研究。每个操作只给出DP行为的部分描述。在本研究中，使用广泛的2f(1)-f(2)和2f(2)-f(1) DP刺激-频率扫描数据对f(1) vs f(2)和f(2)/f(1)比与DP频率的矩阵进行了位置固定/波固定二分法分析：这些数据显示了DP是如何相关的，并提供了2f(1)-f(2)和2f(2)-f(1) DPOAE相位和振幅与频率行为的更完整的图像。相位数据包含了波固定和地点固定发射比例系统变化的证据。结果表明，宽刺激频率比的2f(1)-f(2) dpoae是波固定的，而其他dpoae都是位固定的。在2f(1)-f(2) DP数据区域内以约f(2)/f(1) = 1.1的频率比发生跃迁。2f(1)-f(2) DP和2f(2)-f(1) DP相位行为在f(2)/f(1) = 1边界上是连续的。由于2f(2)-f(1) DP产生区域一定受到DP频率位的强烈影响，因此结果表明，2f(1)-f(2) DP的位置固定分量也与其频率位有关。3f(1)-2f(2)和3f(2)-2f(1) DPs也有类似的规律。结果支持以下模型：对于产生2f(1)-f(2)波定发射的有限刺激条件集，DP能量主要在f(2)区域产生并直接发射。所有其他dpoae都是位置固定的发射，虽然f(2)刺激包络内的非线性仍然是发生器，但DP不是直接发射，而是通过顶部传播，直到基本上通过DP位置区域的单独反射机制重新发射。(C) 2000美国声学学会。[s0001 - 4966(99) 05212 - 1]。
The primary site of generation on the basilar membrane for the 2f(1)-f(2) distortion product (DP) is generally considered to be near where the higher-frequency stimulus tone peaks. This site has also been shown to be a source of DP otoacoustic emission (DPOAE) in the ear canal, but a second source of emission is known to exist in the region of the DP frequency place. The DPOAE phase versus frequency gradient provides a means of investigating the emission mechanisms. ''Wave-fixed'' and ''place-fixed'' mechanisms have been proposed to account for the very different phase gradients found depending on whether the 2f(1)-f(2) DPOAE is evoked by a small or large stimulus-frequency ratio. DPOAE phase versus frequency gradients can be investigated either by sweeping f(1),f(2) or by sweeping both frequencies maintaining a constant frequency ratio. Each manipulation gives only a partial description of DP behavior. In this study, the place-fixed/wave-fixed dichotomy is analyzed using extensive 2 f(1)-f(2) and 2f(2)-f(1) DP stimulus-frequency sweep data presented on matrices of f(1) vs f(2) and f(2)/f(1) ratio versus DP frequency: These show how the DPs are related and provide a more complete picture of 2f(1)-f(2) and 2f(2)-f(1) DPOAE phase and amplitude versus frequency behavior. The phase data contain evidence for a systematic variation in the proportions of wave- and place-fixed emission. The results suggest that 2f(1)-f(2) DPOAEs with a wide stimulus frequency ratio are wave fixed, while all other DPOAEs are place fixed. A transition occurs within the 2f(1)-f(2) DP data region at a frequency ratio of about f(2)/f(1) = 1.1. The 2f(1)-f(2) DP and 2f(2)-f(1) Dp phase behavior is continuous across the f(2)/f(1) = 1 boundary. As the 2f(2)-f(1) DP generation region must be strongly influenced by the DP frequency place, the results imply that the place-fixed component of the 2f(1)-f(2) DP is also linked to its frequency place. A similar pattern was obtained with the 3f(1)-2f(2) and 3f(2)-2f(1) DPs. The results support the following model: For the limited set of stimulus conditions that gives rise to 2f(1)-f(2) wave-fixed emissions, DP energy is largely generated in the f(2) region and is emitted directly. All other DPOAEs are place-fixed emissions, and while nonlinearity within the f(2) stimulus envelope remains the generator, the DP is not directly emitted but travels apically until it is re-emitted basally via a separate reflection mechanism in the region of the DP place. (C) 2000 Acoustical Society of America. [S0001-4966(99)05212-1].