Institute of Physiology and Pathology of Hearing, World Hearing Center, ul. Mokra 17, Kajetany 05-830 Nadarzyn, Poland.
J Acoust Soc Am. 2022 Oct;152(4):2150. doi: 10.1121/10.0014601.
The medial olivocochlear reflex (MOCR), usually assessed by the inhibition of transiently evoked otoacoustic emissions (TEOAEs) with contralateral noise, is a very small effect. In understanding the origin of the MOCR, it is crucial to obtain data of the highest accuracy, i.e., with a high signal-to-noise ratio (SNR), which in turn largely depends on the number of signal averages. This study investigates how the reliability of MOCR measures is affected by the number of averages. At the same time, the effect of the presence of synchronized spontaneous otoacoustic emissions (SSOAEs) is taken into account, as it is known that this factor significantly affects TEOAE amplitudes and SNRs. Each recording session consisted of two series of four measurements, allowing comparison of MOCR magnitude based on 250, 500, 750, and 1000 averages. Reliability was based on comparing the two series. The results show that, for a good quality MOCR measure (i.e., intraclass correlation above 0.9), the required number of averages is at least double that obtainable from a standard TEOAE test (i.e., 500 compared to 250). Ears without SSOAEs needed a higher number of averages to reach a correlation of 0.9 than ears with SSOAEs.
中橄榄耳蜗反射（MOCR），通常通过对侧噪声对瞬态诱发耳声发射（TEOAEs）的抑制来评估，是一种非常小的效应。在了解 MOCR 的起源时，获得最高精度的数据至关重要，即具有高信噪比（SNR），这在很大程度上取决于信号平均的数量。本研究探讨了平均数量对 MOCR 测量可靠性的影响。同时，还考虑了同步自发耳声发射（SSOAEs）的存在的影响，因为众所周知，这一因素会显著影响 TEOAE 幅度和 SNR。每个记录会话包括两个四个测量的系列，允许基于 250、500、750 和 1000 个平均值来比较 MOCR 的幅度。可靠性是基于对两个系列的比较。结果表明，对于高质量的 MOCR 测量（即，组内相关系数高于 0.9），所需的平均数量至少是标准 TEOAE 测试（即 500 与 250）的两倍。没有 SSOAEs 的耳朵需要更多的平均值才能达到 0.9 的相关性，而有 SSOAEs 的耳朵则不需要。
