Vanderbilt Neuroscience Graduate Program, Vanderbilt University, Nashville, TN 37212; Vanderbilt Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37212.
Vanderbilt Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37212.
Hear Res. 2022 Oct;424:108568. doi: 10.1016/j.heares.2022.108568. Epub 2022 Jul 12.
Clinical auditory physiological measures (e.g., auditory brainstem responses, ABRs, and distortion product otoacoustic emissions, DPOAEs) provide diagnostic specificity for differentially diagnosing overt hearing impairments, but they remain limited in their ability to detect specific sites of lesion and subtle levels of cochlear damage. Studies in animal models may hold the key to improve differential diagnosis due to the ability to induce tightly controlled and histologically verifiable subclinical cochlear pathologies. Here, we present a normative set of traditional and clinically novel physiological measures using ABRs and DPOAEs measured in a large cohort of male macaque monkeys. Given the high similarities between macaque and human auditory anatomy, physiology, and susceptibility to hearing damage, this normative data set will serve as a crucial baseline to investigate novel physiological measures to improve diagnostics. DPOAE amplitudes were robust at f = 1.22, L/L = 65/55, increased with frequency up to 10 kHz, and exhibited high test re-test reliability. DPOAE thresholds were lowest from 2-10 kHz and highest < 2 kHz. ABRs with a standard clinical electrode montage (vertex-to-mastoid, VM) produced Waves I-IV with a less frequently observed Wave-I, and lower thresholds. ABRs with a vertex-to-tympanic membrane (VT) electrode montage produced a more robust Wave-I, but absent Waves II-IV and higher thresholds. Further study with the VM montage revealed amplitudes that increased with stimulus level and were largest in response to click stimuli, with Wave-II showing the largest ABR amplitude, followed by -IV and -I, with high inter- and intra-subject variability. ABR wave latencies decreased with stimulus level and frequency. When stimulus presentation rate increased or stimuli were presented in close temporal proximity, ABR amplitude decreased, and latency increased. These findings expand upon existing literature of normative clinical physiological data in nonhuman primates and lay the groundwork for future studies investigating the effects of noise-induced pathologies in macaques.
临床听觉生理测量（例如，听脑干反应，ABR 和畸变产物耳声发射，DPOAE）为鉴别显性听力障碍提供了诊断特异性，但它们在检测特定病变部位和耳蜗损伤细微程度方面的能力仍然有限。由于能够诱导严格控制和组织学可验证的亚临床耳蜗病变，动物模型中的研究可能是改善鉴别诊断的关键。在这里，我们提出了一组使用大型雄性猕猴群体中测量的 ABR 和 DPOAE 的传统和临床新型生理测量的规范集。鉴于猕猴和人类听觉解剖，生理学和听力损伤易感性之间的高度相似性，该规范数据集将作为研究改善诊断的新型生理测量的重要基线。DPOAE 幅度在 f = 1.22，L/L = 65/55 时很强，随着频率增加到 10 kHz，并且表现出高的测试重测可靠性。DPOAE 阈值在 2-10 kHz 之间最低，<2 kHz 之间最高。使用标准临床电极布置（顶点到乳突，VM）产生的 ABR 具有较少出现的 Wave-I 和较低的阈值。使用顶点到鼓膜（VT）电极布置产生的 ABR 具有更强大的 Wave-I，但不存在 Waves II-IV 和更高的阈值。使用 VM 布置的进一步研究表明，随着刺激水平的增加，幅度会增加，并且对点击刺激的反应最大，其中 Wave-II 显示出最大的 ABR 幅度，其次是 -IV 和 -I，具有很高的个体间和个体内变异性。ABR 波潜伏期随刺激水平和频率而降低。当刺激呈现率增加或刺激在时间上接近时，ABR 幅度减小，潜伏期增加。这些发现扩展了非人类灵长类动物正常临床生理数据的现有文献，并为未来研究猕猴噪声诱导病变的影响奠定了基础。
