Otoacoustic Emission Cochleography

标题：耳声发射耳蜗术 计划中的研究旨在提供对两者背后机制的更好理解 DPOAE的产生以及这种发射的大而复杂的响应空间的主要特征。这 通过使用考虑了DPOAE和DPOAE的DPOAE水平/相位(L/P)图来实现总体目标 幅值和相位作为f2/f1比和DPOAE频率的函数。根据人们普遍接受的 DPOAE产生的双源模型，在这些图中，水平相带(浅相斜率与FDP)是 表示来自f2位置的畸变源发射，而垂直相位带状(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(ITS)无法移除所有垂直相位带 人类更高的基音水平，或在存在的情况下提取任何DPOAE反射分量 兔的垂直时相带。目的#1研究垂直相带不利于 它的近FDP取决于原音水平、物种和SFOAEs。因此，兔的DPOAE L/P图谱， 在不同的f1和f2水平上，在FDP附近收集的具有和不具有IT的龙猫和人类将被比较， 并与SFOAE的存在有关，这是反射机制的特征。据推测，OAE 对其近FDP的耐受性来自分布的DPOAE的基础来源，因此起病潜伏期 这些辐射应该比在相同f2下获得的失真辐射短。目标2侧重于 假设根据原声水平和种类，用IFFT提取DPOAE成分 方法可能与IT技术揭示的方法不匹配，因为尽管人类和兔子都展示了 浅的和陡峭的相位梯度DPOAE分量，它们对其近FDP的响应不同。目标#3 研究了DPOAE的基本来源在以下揭示的DPOAE残差中起重要作用的概念 F2以上的音调或噪声频带。这一来源还起到了填补功能障碍区域的作用，如 传统DP-GRAMS。这个基础声源的可能性将通过确定八度音程范围来调查 在其上可以为不同级别的f1和f2产生不同音调(f2-f1)。噪声频段越来越多 相对于f2的更高的低频截止，并且其被放置在高于f2的连续0.33倍频程增量 将被用来揭示噪声破坏后DPOAE L/P图的异常残差，并帮助建立 DPOAE基本来源的存在和性质。最后，DP-gram将在使用和不使用 在4-khz噪声诱发的人类听力图中，它的频率为0.33个八度以上，以确定是否如在 兔，相应的DP-GRAM凹槽的真实范围被基础DPOAE源部分遮盖。 计划中的研究承诺修改关于DPOAE产生机制的公认智慧，以及 也可能导致DPOAE测试的发展，这种测试通过允许准确的耳蜗损伤而更加有用 在信噪比显著提高的较高原色级别上显示的图案。

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.