Adaptation of the electrically evoked compound action potential (ECAP) recorded from nucleus CI24 cochlear implant users
Adaptation of the electrically evoked compound action potential (ECAP) recorded from nucleus CI24 cochlear implant users
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DOI：
10.1097/aud.0b013e318157671f
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发表时间：
2007-12-01
期刊：
影响因子：
3.7
通讯作者：
Brown, Carolyn J.
中科院分区：
文献类型：
--
作者：
Clay, Kelly M. Schmidt;Brown, Carolyn J.
目的：本研究有三个主要目标。第一个目标是评估不同人工耳蜗使用者的神经适应差异程度。第二个目标是确定听觉神经水平的适应是否与单词识别能力相关。第三个目标是确定周围神经适应是否对电诱发复合动作电位 (ECAP) 阈值和 MAP 水平之间的关系产生影响。设计：使用神经反应遥测软件记录 21 名 Nucleus 人工耳蜗用户的 ECAP。在 5 分钟内以三种不同的刺激速率进行了一系列 110 个 ECAP 记录：15、80 和 300 Hz。用于记录这一系列反应的刺激水平保持恒定或接近受试者确定的 300 Hz 刺激率的最大舒适水平（C 水平）。从 5 分钟刺激间隔开始到结束测量的 ECAP 幅度的持续下降被解释为神经适应的证据。然后使用回归分析程序来评估神经适应和单词识别之间的关系。结果：在 80 和 300 Hz 的刺激率下，所有 21 名受试者都观察到了显着的适应水平。当使用 15 Hz 速率时，在 5 分钟记录期内几乎没有观察到适应。适应量在 300 Hz 频率下最大，并且在不同的人工耳蜗使用者之间差异很大。没有发现适应量和单词识别之间存在关系。适应程度也没有显示出影响低速率记录的 ECAP 阈值与用于对语音处理器进行编程的水平之间的关系。 结论：人工耳蜗用户在响应连续电刺激时经历了不同程度的长期适应。即使刺激频率低至 80 Hz，适应对 ECAP 的影响也很明显。尽管适应量的变化可能反映了听神经状态的跨受试者差异，但在这些周围神经功能的生理测量与单词识别或 ECAP 阈值和 MAP 水平之间的关系之间没有发现可预测的关系。
Objective: This study had three main goals. The first goal was to assess the extent to which neural adaptation varied across cochlear implant users. The second goal was to determine whether adaptation at the level of the auditory nerve was correlated with word recognition ability. The third goal was to determine whether peripheral neural adaptation had an impact on the relationship between the electrically evoked compound action potential (ECAP) thresholds and MAP levels.Design: Neural response telemetry software was used to record the ECAP in 21 Nucleus cochlear implant users. A series of 110 ECAP recordings were made over a 5-min period at three different stimulation rates: 15, 80, and 300 Hz. The stimulation levels used to record this series of responses were held constant at or near the level the subject identified as his or her maximum comfort level (C-level) for the 300-Hz stimulation rate. Consistent decreases in ECAP amplitude as measured from the beginning to the end of the 5-min stimulation interval were interpreted as evidence of neural adaptation. Regression analysis procedures were then used to assess the relationship between neural adaptation and word recognition.Results: Significant levels of adaptation were observed for all 21 subjects at stimulation rates of 80 and 300 Hz. Little or no adaptation was observed over the 5-min recording period when the 15-Hz rate was used. The amount of adaptation was greatest at the 300-Hz rate and varied substantially across cochlear implant users. No relationship between the amount of adaptation and word recognition was found. Neither was the degree of adaptation shown to influence the relationship between ECAP thresholds recorded at low rates and the levels used to program the speech processor.Conclusions: Cochlear implant users experienced varying degrees of long-term adaptation in response to continuous electrical stimulation. The effects of adaptation on the ECAP were apparent even at stimulation rates as low as 80 Hz. Although variations in the amount of adaptation are likely to reflect cross-subject differences in the status of the auditory nerve, no predictable relationship was found between these physiologic measures of peripheral neural function and either word recognition or the relationship between ECAP thresholds and MAP levels.