Otoacoustic Emission Cochleography

标题：耳声发射耳蜗造影术 计划中的研究旨在更好地了解两者的机制 DPOAE的产生以及这种发射的大而复杂的响应空间的关键特征。这 通过使用考虑DPOAE水平/相位（L/P）的DPOAE图， 幅值和相位作为f2/f1比和DPOAE频率的函数。根据公认的 2-DPOAE产生的源模型，在这些图中，水平相位带（浅相位斜率与fdp）是 指示来自F2位置的失真源发射，而垂直相位条带（陡峭的相位斜率与 fdp）表示来自DPOAE频率位置（fdp）的反射发射。最近，我们发现， 在这些地图中，放置在fdp附近的干扰音（IT）无法消除所有垂直相位条带， 人类中较高的主色调水平，或者在存在 家兔的垂直相带。目的#1研究了垂直相带难治性的假设。 fdp附近的ITs取决于主色调水平，物种和SFOAE。因此，DPOAE L/P图来自兔， 将比较在不同f1和f2水平下在fdp附近有和没有IT的情况下收集的龙猫和人类， 并与SFOAE的存在有关，这是反射机制的特征。据推测，OAE fdp附近的IT难治性来自DPOAE的分布性基底源，因此 这些发射应该短于对于相同F2获得的失真发射。目标#2专注于 假设DPOAE分量的提取依赖于主声电平和种属， 方法可能与IT技术所揭示的方法不匹配，因为尽管人类和兔子都表现出 浅和陡峭的相位梯度DPOAE分量，他们在他们的响应不同的ITs附近fdp。目标3 研究了DPOAE的基础源在DPOAE残差中起重要作用的概念， 高于F2的噪声音调或频带。这一来源还起到“填补”功能障碍区域的作用，如 传统的DP-gram。这种基底源的可能性将通过确定倍频程范围来研究 在此基础上，可以针对不同级别的f1和f2产生不同的音调（f2-f1）。噪音带越来越多 相对于f2的更高低频截止值和在f2之上以连续0.33倍频程增量放置的IT 将用于揭示噪声损伤后DPOAE L/P图中的异常残差，并帮助建立 DPOAE基础源的存在和性质。最后，将在有和没有 在听力图中具有4 kHz噪声诱导缺口的人类中，IT高于f2 0.33个倍频程，以确定是否如 兔，相应的DP-gram切迹的真实范围部分被基底DPOAE源掩盖。 计划中的研究承诺修改关于DPOAE产生机制的公认知识， 也可能导致DPOAE测试的发展，更有用的是允许准确的耳蜗损伤， 在信噪比显著提高的较高主色调水平下显示的模式。

Title: Otoacoustic Emission Cochleography The planned research is designed to provide an improved understanding of the mechanisms underlying both the generation of DPOAEs as well as the key features of this emission's large, complex response space. This general aim is being accomplished by using DPOAE level/phase (L/P) maps that consider both DPOAE magnitude and phase as a function of f2/f1 ratio and DPOAE frequency. According to the commonly accepted 2-source model of DPOAE generation, in these maps, horizontal-phase banding (shallow phase slope vs fdp) is indicative of distortion-source emissions from the f2 place, while vertical-phase banding (steep phase slope vs fdp) signifies reflection emissions from the DPOAE-frequency place (fdp). Recently, we discovered that interference tones (ITs) placed near fdp in these maps were unable to remove all vertical-phase banding at higher primary-tone levels in humans, or to extract any DPOAE-reflection components in the presence of vertical-phase banding in rabbits. Aim #1 investigates the hypothesis that vertical-phase banding refractory to ITs near fdp depends on primary-tone level, species, and SFOAEs. Thus, DPOAE L/P maps from rabbits, chinchillas, and humans collected with and without an IT near fdp at various f1 and f2 levels will be compared, and related to the presence of SFOAEs, a signature of the reflection mechanism. It is postulated that OAEs refractory to ITs near fdp arise from a distributed basal source of DPOAEs and therefore onset latencies of these emissions should be shorter than distortion emissions obtained for the same f2. Aim #2 focuses on the hypothesis that depending upon primary-tone levels and species, DPOAE components extracted with IFFT methods may not match those revealed by IT techniques because, while both humans and rabbits exhibit shallow and steep phase-gradient DPOAE components, they differ in their response to ITs near fdp. Aim #3 investigates the notion that a basal source of DPOAEs plays a substantial role in DPOAE residuals revealed by tones or bands of noise above f2. This source also acts to `fill in' regions of dysfunction as revealed by traditional DP-grams. The likelihood of this basal source will be investigated by determining the octave extent over which difference tones (f2-f1) can be produced for various levels of f1 and f2. Noisebands with increasingly higher low-frequency cutoffs with respect to f2 and ITs placed at successive 0.33-octave increments above f2 will be used to reveal abnormal residuals in DPOAE L/P maps following noise damage and help establish the presence and properties of a basal source of DPOAEs. Finally, DP-grams will be collected with and without an IT 0.33 octaves abovef2 in humans with 4-kHz noise-induced notches in their audiograms to determine if, as in rabbits, the true extent of the corresponding DP-gram notch is partially obscured by a basal DPOAE source. The planned studies promise to modify accepted wisdom regarding mechanisms of DPOAE generation, and may also lead to the development of DPOAE tests that are more useful by allowing accurate cochlear-damage patterns to be revealed at higher primary-tone levels where signal-to-noise ratios are notably improved.