Background

The auditory brainstem response (ABR), specifically wave I, is widely used to noninvasively measure auditory nerve (AN) function. Recent work in humans has introduced novel electrocochleographic measures to comprehensively characterize AN function that emphasize suprathreshold processing and estimate neural synchrony.

New Method

This study establishes new tools for evaluating AN function in vivo in adult mice using tone-evoked ABRs obtained from young-adult CBA/CaJ mice, adapting the approach previously introduced in humans. Six metrics are obtained from ABR wave I at suprathreshold stimulus levels.

Results

Change-point analyses show that the metrics’ rate of change with stimulus level differs between moderate and high suprathreshold levels, suggesting that this approach can potentially characterize the presence of heterogeneous AN fiber types.

Comparison with existing methods

Traditional ABR approaches focus on response thresholds and averaged amplitudes/latencies. In contrast, our multi-metric approach, which uses single-trial data and suprathreshold stimuli, provides novel information and identifies evidence of neural synchrony deficits and changes in the heterogeneity of AN fibers underlying AN behavior.

Conclusion

The techniques reported here provide a novel tool to assess changes in AN function in vivo in a commonly used animal model. A benchmark of most current hearing research is the transition from animal to human studies. Here we established a translational objective approach, applying methods that were first developed in humans to animals. This approach enables researchers to identify changes in AN function arising from the animal models with well-characterized pathology, and predict similar pathological changes in human AN dysfunction and hearing loss.

中文翻译：

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使用听觉脑干反应表征小鼠周围听神经功能的多指标方法。

 背景

听性脑干反应 (ABR)，特别是波 I，广泛用于无创测量听神经 (AN) 功能。最近的人类工作引入了新颖的耳蜗电图​​测量方法来全面表征强调超阈值处理和估计神经同步性的 AN 功能。

 新方法

这项研究建立了新的工具，使用从年轻成年 CBA/CaJ 小鼠获得的音调诱发 ABR 来评估成年小鼠体内的 AN 功能，并采用了先前在人类中引入的方法。从超阈值刺激水平的 ABR 第一波中获得了六个指标。

 结果

变化点分析表明，指标随刺激水平的变化率在中度和高阈值水平之间有所不同，表明这种方法可以潜在地表征异质 AN 纤维类型的存在。

与现有方法的比较

传统的 ABR 方法侧重于响应阈值和平均幅度/延迟。相比之下，我们的多度量方法使用单次试验数据和阈上刺激，提供了新颖的信息，并识别了神经同步缺陷和 AN 行为背后的 AN 纤维异质性变化的证据。

 结论

这里报道的技术提供了一种新的工具来评估常用动物模型体内AN 功能的变化。当前大多数听力研究的一个基准是从动物研究到人类研究的转变。在这里，我们建立了一种转化客观方法，将最初在人类身上开发的方法应用于动物。这种方法使研究人员能够识别具有明确病理特征的动物模型引起的 AN 功能变化，并预测人类 AN 功能障碍和听力损失的类似病理变化。