Institute of Physiology and Pathology of Hearing, Warsaw, Poland.
World Hearing Center, Kajetany, Nadarzyn, Poland.
Ear Hear. 2021 July/Aug;42(4):990-1005. doi: 10.1097/AUD.0000000000000996.
The function of the medial olivocochlear system can be evaluated by measuring the suppression of otoacoustic emissions (OAEs) by contralateral stimulation. One of the obstacles preventing the clinical use of the OAE suppression is that it has considerable variability across subjects. One feature that tends to differentiate subjects is the presence or absence of spontaneous OAEs (SOAEs). The purpose of the present study was to investigate the reliability of contralateral suppression of transiently evoked OAEs (TEOAEs) measured using a commercial device in ears with and without SOAEs.
OAEs were recorded in a group of 60 women with normal hearing. TEOAEs were recorded with a linear protocol (identical stimuli), a constant stimulus level of 65 dB peSPL, and contralateral broadband noise (60 dB SPL) as a suppressor. Each recording session consisted of three measurements: the first two were made consecutively without taking out the probe (the "no refit" condition); the third measurement was made after taking out and refitting the probe (a "refit" condition). Global (for the whole signal) and half-octave band values of TEOAE response levels, signal-to-noise ratios (SNRs), raw dB TEOAE suppression, and normalized TEOAE suppression, and latency were investigated. Each subject was tested for the presence of SOAEs using the synchronized SOAE (SSOAE) technique. Reliability was evaluated by calculating the intraclass correlation coefficient, standard error of measurement (SEM) and minimum detectable change.
The TEOAE suppression was higher in ears with SSOAEs in terms of normalized percentages. However, when calculated in terms of decibels, the effect was not significant. The reliability of the TEOAE suppression as assessed by SEM was similar for ears with and without SSOAEs. The SEM for the whole dataset (with and without SSOAEs) was 0.08 dB for the no-refit condition and 0.13 dB for the refit condition (equivalent to 1.6% and 2.2%, respectively). SEMs were higher for half-octave bands than for global values. TEOAE SNRs were higher in ears with SSOAEs.
The effect of SSOAEs on reliability of the TEOAE suppression remains complicated. On the one hand, we found that higher SNRs generally provide lower variability of calculated suppressions, and that the presence of SSOAEs favors high SNRs. On the other hand, reliability estimates were not much different between ears with and without SSOAEs. Therefore, in a clinical setting, the presence of SOAEs does not seem to have an effect on suppression measures, at least when testing involves measuring global or half-octave band response levels.
通过测量对侧刺激对耳声发射（OAE）的抑制作用，可以评估内侧橄榄耳蜗系统的功能。对侧刺激抑制作用在临床上的应用受到限制的一个原因是，它在不同个体之间存在相当大的变异性。一个倾向于区分个体的特征是自发 OAE（SOAE）的存在与否。本研究的目的是探讨使用商业设备测量瞬态诱发 OAE（TEOAEs）的对侧抑制在有和无 SOAE 的耳朵中的可靠性。
在一组 60 名听力正常的女性中记录 OAE。使用线性方案（相同的刺激）、65 dB peSPL 的恒定刺激水平和 60 dB SPL 的宽带噪声（作为抑制剂）记录 TEOAEs。每个记录会话包括三个测量：前两个连续进行，不取出探头（“无重新插入”条件）；第三个测量在取出和重新插入探头后进行（“重新插入”条件）。研究了 TEOAE 响应水平、信噪比（SNR）、原始 dB TEOAE 抑制和归一化 TEOAE 抑制以及潜伏期的全局（整个信号）和半倍频程带值。使用同步 SOAE（SSOAE）技术检查每个受试者是否存在 SOAE。通过计算组内相关系数、测量标准误差（SEM）和最小可检测变化来评估可靠性。
在 SSOAE 存在的情况下，TEOAE 抑制以归一化百分比的形式更高。然而，当以分贝表示时，效果并不显著。使用 SEM 评估的 TEOAE 抑制的可靠性在有和无 SSOAE 的耳朵中相似。无 refit 条件下整个数据集（有和无 SSOAE）的 SEM 为 0.08 dB，refit 条件下为 0.13 dB（分别相当于 1.6%和 2.2%）。半倍频程带的 SEM 高于全局值。在 SSOAE 存在的情况下，TEOAE SNR 更高。
SSOAE 对 TEOAE 抑制可靠性的影响仍然很复杂。一方面，我们发现较高的 SNR 通常提供较低的计算抑制变异性，并且 SSOAE 的存在有利于较高的 SNR。另一方面，有和无 SSOAE 的耳朵之间的可靠性估计没有太大差异。因此，在临床环境中，SOAE 的存在似乎不会对抑制测量产生影响，至少在测试涉及测量全局或半倍频程带响应水平时是这样。
