Alemi Razieh, Lehmann Alexandre
Department of Otolaryngology, Faculty of Medicine, McGill University, Montreal, QC, Canada.
Centre for Research on Brain, Language and Music (CRBLM), Montreal, QC, Canada.
J Am Acad Audiol. 2019 May;30(5):396-405. doi: 10.3766/jaaa.18014. Epub 2019 Apr 26.
Cochlear implant (CI) outcomes can be assessed using objective measures that reflect the integrity of the auditory pathway. One such measure is the middle latency response (MLR), which can provide valuable information for clinicians.
Traditional stimuli for evoking MLRs, that is, clicks or tone bursts, do not stimulate all parts of the cochlea simultaneously, whereas chirp stimuli compensate for the cochlear neural delay and, therefore, produce more synchronous responses from the different neural elements of the cochlea. The purpose of the present study was to determine whether chirp stimuli can elicit reliable MLRs in CI users and whether those responses correlate with clinical outcomes and with deprivation-related factors.
We presented 2,000 free-field optimized chirp stimuli to CI and control participants while their electroencephalography (EEG) was being recorded.
Twenty-four adult CI users and 24 matched normal-hearing (NH) individuals (age range from 18 to 63 years) participated in this study.
The EEG was recorded from 64 active electrodes placed on the scalp. EEG signals were processed using EEGLAB and ERPLAB toolboxes. We characterized the latencies and amplitudes of the different MLR components in both groups.
Chirp stimuli reliably evoked qualitatively similar MLRs across all NH and CI participants with a couple of differences observed between the NH and CI group. Among the different MLR components, the Na latency was significantly shorter for the CI group. A significant amplitude difference was also found between groups for the Pa-Nb complex, with higher amplitudes observed in the NH group. Finally, there were no significant correlations between MLR latencies (or amplitudes) and clinical outcomes or deprivation-related measures.
Free-field-presented optimized chirp stimuli were shown to evoke measurable and reliable MLRs in CI users. In this experiment, the MLR morphology in CI users was similar to those observed in NH participants. Even though we did not replicate here a significant relationship between MLR and speech perception measures, we were able to successfully collect acoustically evoked MLRs, which could constitute an important supplemental measure to the standard behavioral tests presently being used in postoperative clinical evaluation settings.
人工耳蜗（CI）的效果可以通过反映听觉通路完整性的客观指标来评估。其中一项指标是中潜伏期反应（MLR），它可以为临床医生提供有价值的信息。
用于诱发MLR的传统刺激，即短声或短纯音，不会同时刺激耳蜗的所有部分，而线性调频脉冲刺激可补偿耳蜗神经延迟，因此能从耳蜗的不同神经元件产生更同步的反应。本研究的目的是确定线性调频脉冲刺激能否在CI使用者中诱发可靠的MLR，以及这些反应是否与临床结果和与剥夺相关的因素相关。
我们在记录CI使用者和对照参与者的脑电图（EEG）时，向他们呈现了2000个自由场优化的线性调频脉冲刺激。
24名成年CI使用者和24名匹配的正常听力（NH）个体（年龄范围为18至63岁）参与了本研究。
从放置在头皮上的64个有源电极记录EEG。使用EEGLAB和ERPLAB工具箱对EEG信号进行处理。我们对两组中不同MLR成分的潜伏期和振幅进行了特征描述。
线性调频脉冲刺激在所有NH和CI参与者中可靠地诱发了质量上相似的MLR，在NH组和CI组之间观察到一些差异。在不同的MLR成分中，CI组的Na潜伏期明显更短。两组之间在Pa-Nb复合波上也发现了显著的振幅差异，NH组的振幅更高。最后，MLR潜伏期（或振幅）与临床结果或剥夺相关指标之间没有显著相关性。
自由场呈现的优化线性调频脉冲刺激在CI使用者中能诱发可测量且可靠的MLR。在本实验中，CI使用者的MLR形态与在NH参与者中观察到的相似。尽管我们在此没有重现MLR与言语感知指标之间的显著关系，但我们能够成功收集听觉诱发的MLR，这可能构成目前术后临床评估中使用的标准行为测试的一项重要补充措施。
