Auditory brainstem response (ABR) and cochlear compound action potential (CAP) are widely used for hearing assessment. Due to easy detection, ABR is more commonly used to evaluate cochlear lesions than CAP. Since ABR reflects the central auditory response in the brain, and CAP reflects the auditory nerve function of the cochlea, ABR is not the same as CAP. In order to see the difference between ABR and CAP, two cochlear injury models were observed. In ae noise-induced cochlear damage model, chinchillas were exposed to 105 dB SPL narrow-band noise for 5 hours. One day after the noise, the thresholds of CAP and ABR increased to the same level with permanent hair cell loss. 30 days later, the elevated CAP threshold remains unchanged, but the ABR threshold was significantly reduced about 20 dB. This phenomenon may be due to the irreversible weakening of CAP and the enhancement of ABR by central reorganizition. In another experimental model of unilateral cochlear destruction in guinea pigs, both ABR and CAP were affected by cross-hearing. When ABR was tested from the destroyed ear, a shadow-curve of ABR from the contralateral healthy ear masked the hearing loss in the destroyed ear. In contrast, the typical CAP waveform disappeared which was replaced by an ABR-like waveform from the opposite healthy ear. The results indicate that ABR may not faithfully reflect the functional status of the cochlea, and provide a clue of the occurrence of cross-hearing when subjects have asymmetric hearing loss.

中文翻译：

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听觉脑干反应能否准确反映耳蜗功能？

听觉脑干反应 (ABR) 和耳蜗复合动作电位 (CAP) 被广泛用于听力评估。由于易于检测，ABR 比 CAP 更常用于评估耳蜗病变。由于ABR反映大脑的中枢听觉反应，CAP反映耳蜗的听觉神经功能，因此ABR与CAP不同。为了看到 ABR 和 CAP 之间的差异，观察了两种耳蜗损伤模型。在 ae 噪声引起的耳蜗损伤模型中，龙猫暴露于 105 dB SPL 窄带噪声下 5 小时。噪音发生一天后，CAP 和 ABR 的阈值增加到与永久性毛细胞丢失相同的水平。30 天后，升高的 CAP 阈值保持不变，但 ABR 阈值显着降低了约 20 dB。这种现象可能是由于 CAP 的不可逆弱化和中央重组导致 ABR 的增强。在豚鼠单侧耳蜗破坏的另一个实验模型中，ABR 和 CAP 都受到交叉听力的影响。当从受损耳朵测试 ABR 时，来自对侧健康耳朵的 ABR 阴影曲线掩盖了受损耳朵的听力损失。相比之下，典型的 CAP 波形消失了，取而代之的是来自对侧健康耳朵的类似 ABR 的波形。结果表明，ABR 可能不能如实反映耳蜗的功能状态，并为受试者出现不对称听力损失时交叉听力的发生提供了线索。ABR 和 CAP 都受到交叉听证会的影响。当从受损耳朵测试 ABR 时，来自对侧健康耳朵的 ABR 阴影曲线掩盖了受损耳朵的听力损失。相比之下，典型的 CAP 波形消失了，取而代之的是来自对侧健康耳朵的类似 ABR 的波形。结果表明，ABR 可能不能如实反映耳蜗的功能状态，并为受试者出现不对称听力损失时交叉听力的发生提供了线索。ABR 和 CAP 都受到交叉听证会的影响。当从受损耳朵测试 ABR 时，来自对侧健康耳朵的 ABR 阴影曲线掩盖了受损耳朵的听力损失。相比之下，典型的 CAP 波形消失了，取而代之的是来自对侧健康耳朵的类似 ABR 的波形。结果表明，ABR 可能不能如实反映耳蜗的功能状态，并为受试者出现不对称听力损失时交叉听力的发生提供了线索。