Extraction of sources of distortion product otoacoustic emissions by onset-decomposition
Extraction of sources of distortion product otoacoustic emissions by onset-decomposition
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DOI：
10.1016/j.heares.2009.06.002
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发表时间：
2009-10-01
期刊：
影响因子：
2.8
通讯作者：
Gummer, Anthony W.
中科院分区：
文献类型：
--
作者：
Vetesnik, Ales;Turcanu, Diana;Gummer, Anthony W.
畸变产物耳声发射（DPOAE）的立方分量响应于频率为f（1）和f（2）的两个音调，由耳蜗中的所谓的初级源和次级源机制产生。由此产生的两个源组件之间的干扰可以限制DPOAE在评估耳蜗功能中的有用性。虽然技术可用于分离的源组件，根据应用程序，它们可以是耗时的或无效的，没有先验知识的最佳参数。在这里，我们调查，在人类中，分离的源组件在时域中通过采样的DPOAE时间信号的起始和偏移在适当的时刻的可能性。因此，发展了一种DPOAE范例，其中f（2）音在f（1）音持续存在期间周期性地打开。F-2以20 Hz的步长从1.5 kHz增加到2.5 kHz，并且f（2）/f（1）的比值保持恒定在1.2;在六个主要音调级别进行测量，范围从L-2 = 25到65 dB SPL为了研究通过适当的采样分离两个源的可能性，我们开发了一种称为起始分解的算法。该算法是基于在不同的时刻在发病的DPOAE信号的DPOAE响应构造DP-图的形状属性。因此，在每一个这样的时刻，源组件提取相应的DP-gram的时间窗口。这些分离的主要和次要源组件的振幅起始的时间过程提供的证据，在次要源组件开始显着影响DPOAE的主要源组件的干扰之前，主要源组件达到其稳定状态。因此，在最后的范例中，通过在f（2）刺激音开始之后、在次级分量开始干扰之前的单个预定义时刻对DPOAE信号进行采样来提取初级源分量。基于DP-图中几乎不存在干扰最大值和最小值，对于刺激集中的所有频率和强度，适当的采样时刻为8-10 ms。提取的起始采样的主要来源的优点是，当一个给定的f2单独的源组件进行调查，有没有必要测量DP-gram. In结论，它表明，该技术可以可靠地和快速地分离的源组件，使其成为一个有吸引力的范例，在基础研究和临床诊断的应用。(C)2009 Elsevier B. V.保留所有权利。
The cubic component of the distortion product otoacoustic emission (DPOAE) in response to two tones of frequency f(1) and f(2) is generated by so-called primary- and secondary-source mechanisms in the cochlea. Interference between the resulting two source components can limit the usefulness of DPOAEs in assessing cochlear function. Although techniques are available for separating the source components, depending on the application, they can be either time-consuming or ineffective without a priori knowledge of optimal parameters. Here, we investigated, in humans, the possibility of separating the source components in the time-domain by sampling the onset and offset of the DPOAE-time signal at appropriate instants. Therefore, a DPOAE paradigm was developed in which the f(2) tone was periodically switched on during the continuous presence of the f(1) tone. F-2 was increased in 20-Hz steps from 1.5 to 2.5 kHz and the ratio f(2)/f(1) held constant at 1.2; measurements were made at six primary tone levels, ranging from L-2 = 25 to 65 dB SPL To investigate the possibility of separating the two sources by appropriate sampling, we developed an algorithm called onset-decomposition. The algorithm is based on the shape properties of DP-grams constructed from DPOAE responses at different time instants in the onset of the DPOAE signal. Thus, at each such time instant, the source components were extracted by time-windowing of the corresponding DP-gram. The time courses of the amplitude onsets of these separated primary- and secondary-source components provided evidence that the primary-source component attained its steady-state before the secondary-source component started to significantly influence the DPOAE by interference with the primary-source component. Consequently, in the final paradigm, the primary-source component is extracted by sampling the DPOAE signal at a single pre-defined time instant after the onset of the f(2) stimulus tone, before the secondary component begins to interfere. Based on the near-absence of interference maxima and minima in the DP-grams, the appropriate sampling instant was 8-10 ms for all frequencies and intensities in the stimulus set. Extracting the primary-source by onset sampling has the advantage that when individual source components for a given f2 are to be investigated, there is no need to measure a DP-gram. In conclusion, it is shown that the technique can reliably and quickly separate the source components, making it an attractive paradigm for applications in basic research and clinical diagnosis. (C) 2009 Elsevier B.V. All rights reserved.