Department of Information Technology and Electrical Engineering, ETH Zürich (ETHZ), Zürich, Switzerland; Laboratory of Experimental Audiology, ENT Department, University Hospital and University of Zürich, Zürich, Switzerland.
Laboratory of Experimental Audiology, ENT Department, University Hospital and University of Zürich, Zürich, Switzerland.
Hear Res. 2019 Sep 1;380:187-196. doi: 10.1016/j.heares.2019.07.004. Epub 2019 Jul 9.
Auditory nerve fibers' (ANFs) refractoriness and facilitation can be quantified in electrically evoked compound action potentials (ECAPs) recorded via neural response telemetry (NRT). Although facilitation has been observed in animals and human cochlear implant (CI) recipients, no study has modeled this in human CI users until now. In this study, recovery and facilitation effects at different masker and probe levels for three test electrodes (E6, E12 and E18) in 11 CI subjects were recorded. The ECAP recovery and facilitation were modeled by exponential functions and the same function used for +10 CL masker offset condition can be applied to all other masker offsets measurements. Goodness of fit was evaluated for the exponential functions. A significant effect of probe level was observed on a recovery time constant which highlights the importance of recording the recovery function at the maximum acceptable stimulus level. Facilitation time constant and amplitude showed no dependency on the probe level. However, facilitation was stronger for masker level at or around the threshold of the ECAP (T-ECAP). There was a positive correlation between facilitation magnitude and amplitude growth function (AGF) slope, which indicates that CI subjects with better peripheral neural survival have stronger facilitation.
听觉神经纤维（ANF）的不应期和易化可在通过神经反应遥测术（NRT）记录的电诱发复合动作电位（ECAP）中进行量化。尽管在动物和人类耳蜗植入（CI）受者中已经观察到易化现象，但直到现在，还没有研究对人类 CI 用户进行建模。在这项研究中，记录了 11 名 CI 受者的三个测试电极（E6、E12 和 E18）在不同掩蔽和探测水平下的恢复和易化效应。ECAP 的恢复和易化通过指数函数进行建模，用于+10 CL 掩蔽器偏移条件的相同函数可应用于所有其他掩蔽器偏移测量。对指数函数进行了拟合优度评估。探测水平对恢复时间常数有显著影响，这突出了在最大可接受刺激水平记录恢复函数的重要性。易化时间常数和幅度与探测水平无关。然而，对于 ECAP（T-ECAP）阈值或接近阈值的掩蔽器水平，易化更强。易化幅度与幅度增长函数（AGF）斜率之间存在正相关，这表明具有更好的外周神经存活的 CI 受者具有更强的易化。
