Konrad-Martin Dawn, Keefe Douglas H
VA RR&D National Center For Rehabilitative Auditory Research, Portland VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, USA.
J Acoust Soc Am. 2003 Oct;114(4 Pt 1):2021-43. doi: 10.1121/1.1596170.
Time-frequency representations (TFRs) of otoacoustic emissions (OAEs) provide information simultaneously in time and frequency that may be obscured in waveform or spectral analyses. TFRs were applied to transient-evoked stimulus-frequency (SF) and distortion-product (DP) OAEs to test cochlear model predictions. SFOAEs and DPOAEs were elicited in 18 normal-hearing subjects using gated tones and tone pips. Synchronous spontaneous (SS) OAEs were measured to assess their contributions to SFOAEs and DPOAEs. A common form of TFR of measured OAEs was a collection of frequency-specific components often aligned with SSOAE sites, with each component characterized by one or more brief segments or a single long-duration segment. The spectral envelope of evoked OAEs differed from that of the evoking stimulus. Strong emission regions or cochlear "hot spots" were detected, and sometimes accounted for OAE energy observed outside the stimulus bandwidth. Contributions of hot spots and multiple internal reflections to the OAE, and differences between measured and predicted OAE spectra, increased as stimulus level decreased, consistent with level-dependent changes in the estimated cochlear reflectance. Suppression and frequency-pulling effects between components were observed. A recursive formulation was described for the linear coherent reflection emission theory [Zweig and Shera, J. Acoust. Soc. Am. 98, 2018-2047 (1995)] that is well suited for time-domain calculations.
耳声发射（OAE）的时频表征（TFR）能同时在时间和频率上提供信息，而这些信息在波形或频谱分析中可能会被掩盖。TFR被应用于瞬态诱发刺激频率（SF）和畸变产物（DP）耳声发射，以检验耳蜗模型的预测。使用门控音和短音在18名听力正常的受试者中诱发了刺激频率耳声发射（SFOAE）和畸变产物耳声发射（DPOAE）。测量了同步自发性（SS）耳声发射，以评估它们对SFOAE和DPOAE的贡献。测量到的耳声发射的一种常见TFR形式是一组频率特异性成分，这些成分通常与SSOAE部位对齐，每个成分的特征是一个或多个短暂片段或一个单一的长时程片段。诱发耳声发射的频谱包络与诱发刺激的频谱包络不同。检测到了强发射区域或耳蜗“热点”，有时这些区域解释了在刺激带宽之外观察到的耳声发射能量。随着刺激强度降低，热点和多次内部反射对耳声发射的贡献以及测量的和预测的耳声发射频谱之间的差异增加，这与估计的耳蜗反射率的强度依赖性变化一致。观察到了成分之间的抑制和频率牵引效应。描述了一种适用于时域计算的线性相干反射发射理论[茨威格和谢拉，《美国声学学会杂志》98，2018 - 2047（1995）]的递归公式。
