Zelle Dennis, Bader Katharina, Dierkes Linda, Gummer Anthony W, Dalhoff Ernst
Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany.
Department of Otolaryngology, Head and Neck Surgery, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn- Straße 5, 72076 Tübingen, Germany.
J Acoust Soc Am. 2020 May;147(5):3169. doi: 10.1121/10.0001142.
Distortion-product otoacoustic emissions (DPOAEs) emerge from the cochlea when elicited with two tones of frequencies f and f. DPOAEs mainly consist of two components, a nonlinear-distortion and a coherent-reflection component. Input-output (I/O) functions of DPOAE pressure at the cubic difference frequency, f=2f-f, enable the computation of estimated distortion-product thresholds (EDPTs), offering a noninvasive approach to estimate auditory thresholds. However, wave interference between the DPOAE components and suboptimal stimulus-level pairs reduces the accuracy of EDPTs. Here, the amplitude P of the nonlinear-distortion component is extracted from short-pulse DPOAE time signals. DPOAE level maps representing the growth behavior of P in L,L space are recorded for 21 stimulus-level pairs and 14 frequencies with f=1 to 14 kHz (f/f=1.2) from 20 ears. Reproducing DPOAE growth behavior using a least-squares fit approach enables the derivation of ridge-based I/O functions from model level maps. Objective evaluation criteria assess the fit results and provide EDPTs, which correlate significantly with auditory thresholds (p < 0.001). In conclusion, I/O functions derived from model level maps provide EDPTs with high precision but without the need of predefined optimal stimulus-level pairs.
当用频率为f1和f2的两个纯音诱发时，畸变产物耳声发射（DPOAE）从耳蜗中产生。DPOAE主要由两个成分组成，即非线性畸变成分和相干反射成分。在立方差频f2=2f1-f2处的DPOAE声压的输入-输出（I/O）函数能够计算估计的畸变产物阈值（EDPT），从而提供一种估计听阈的非侵入性方法。然而，DPOAE成分之间的波干扰和次优刺激水平对会降低EDPT的准确性。在此，从短脉冲DPOAE时间信号中提取非线性畸变成分的幅度P。针对来自20只耳朵的21对刺激水平和14个频率（f1=1至14kHz，f2/f1=1.2）记录表示P在L1、L2空间中增长行为的DPOAE水平图。使用最小二乘拟合方法再现DPOAE增长行为能够从模型水平图中推导基于脊的I/O函数。客观评估标准评估拟合结果并提供EDPT，其与听阈显著相关（p<0.001）。总之，从模型水平图推导的I/O函数能够高精度地提供EDPT，而无需预定义的最佳刺激水平对。
