IEEE Trans Biomed Eng. 2011 Aug;58(8). doi: 10.1109/TBME.2011.2157154. Epub 2011 May 19.
Distortion product otoacoustic emissions (DPOAEs) are widely used as an objective examination procedure to determine cochlear function. In a clinical routine setting, the amplitude of the DPOAE signal at 2f1 .. f2 is applied as an indicator for a potential hearing loss up to 8 kHz. Due to their poor signal to noise ratio, meatal nodes from standing waves and calibration issues, high-frequency DPOAEs > 8 kHz have hardly been addressed in experimental and clinical audiology so far. Here, we present a new method of measuring DPOAE signal levels based on optimal maximum likelihood estimation with windowed power spectral density estimation of stochastic signals and filtering theory. Analysis of simulated data showed that the proposed method effectively reduces the disturbing noise floor compared to conventional averaging techniques. Robust DPOAE signals were measured in 20 ears from 10 normally hearing young adults (21 to 27 years) from 0:5 to 18 kHz. Repeated DPOAE recordings in one individual yielded a good to very good testretest reliability of the proposed method. These observations are discussed in the context of DPOAE signal processing and possible clinical applications of high-frequency DPOAE measurements.
畸变产物耳声发射（DPOAE）被广泛用作一种客观的检查程序，用于确定耳蜗功能。在临床常规设置中，2f1 至 f2 处的 DPOAE 信号幅度用作高达 8 kHz 的潜在听力损失的指标。由于信噪比差、驻波的耳道节点和校准问题，高频 DPOAE（>8 kHz）在实验和临床听力学中几乎没有得到解决。在这里，我们提出了一种新的基于最佳似然估计的测量 DPOAE 信号水平的方法，该方法对随机信号的加窗功率谱密度估计和滤波理论进行了分析。对模拟数据的分析表明，与传统的平均技术相比，该方法有效地降低了干扰噪声基底。从 10 名听力正常的年轻成年人（21 至 27 岁）的 20 只耳朵中测量了 0.5 至 18 kHz 的稳健 DPOAE 信号。一个人重复的 DPOAE 记录表明，该方法具有良好到非常好的测试-重测可靠性。这些观察结果在 DPOAE 信号处理的背景下进行了讨论，并讨论了高频 DPOAE 测量的可能临床应用。
