背景:在儿科的大型数据集中,外耳放大(EEA)已显示为5-19dB-A。青春期,和成人参与者。然而,可变EEA是一个被忽视的特征,可能在个体噪声诱发的听力损失(NIHL)易感性中起作用。变化5-19dB-A的噪声暴露转化为高EEA个体理论上比低EEA个体经历3-4倍大的NIHL风险。
目的:本初步分析的目的是检验以下假设:较高的EEA与噪声引起的阈值偏移敏感性增加相关。
方法:将9只龙猫暴露于89dB-SPL的4-kHz倍频程噪声中24小时。暴露前获得听觉脑干反应阈值,暴露后24小时,暴露后4周。分析了EEA与阈值偏移之间的关系。
结果:开耳EEA范围为11-19dB-SPL,闭塞耳EEA范围为10-21dB-SPL。较高的阻塞耳EEA与NIHL易感性增加相关(p=0.04),较低的体重(p=0.01)。雄性动物比雌性动物表现出更多的阈值偏移(p=0.02),体重低于雌性动物(p=0.02),和较高的闭塞耳EEA(男性平均值=18dB;女性平均值=15dB)。
结论:综合来看,在最小的动物中观察到阈值偏移易感性增加,具有最高阻塞耳朵EEA的动物,和雄性动物(往往具有较高的闭塞耳朵EEA)。鉴于较小的身体尺寸和较高的阻塞耳朵EEA之间的既定关系,这些初步结果表明,身体大小(和阻塞的耳朵EEA;身体大小的函数)可能是一个潜力,NIHL易感性差异的潜在驱动因素,而不是真正的性别差异。
BACKGROUND: External-ear amplification (EEA) has been shown to vary from 5-19 dB-A in large datasets of pediatric, adolescent, and adult human participants. However, variable EEA is an overlooked characteristic that likely plays a role in individual noise-induced hearing loss (NIHL) susceptibility. A noise exposure varying 5-19 dB-A translates to high-EEA individuals theoretically experiencing 3-4 times greater NIHL risk than low-EEA individuals.
OBJECTIVE: The purpose of this preliminary analysis was to test the hypothesis that higher EEA is correlated with increased noise-induced threshold shift susceptibility.
METHODS: Nine chinchillas were exposed to 4-kHz octave-band noise at 89 dB-SPL for 24 h. Auditory brainstem response thresholds were obtained pre-exposure, 24-h post-exposure, and 4-week post-exposure. Relationships between EEA and threshold shift were analyzed.
RESULTS: Open-ear EEA ranged 11-19 dB-SPL, and occluded-ear EEA ranged 10-21 dB-SPL. Higher occluded-ear EEA was correlated with increased NIHL susceptibility (p = 0.04), as was lower body weight (p = 0.01). Male animals exhibited more threshold shift than female animals (p = 0.02), lower body weight than female animals (p = 0.02), and higher occluded-ear EEA (male mean = 18 dB; female mean = 15 dB).
CONCLUSIONS: Taken together, increased threshold shift susceptibility was observed in the smallest animals, animals with the highest occluded-ear EEA, and in male animals (which tended to have higher occluded-ear EEA). Given the established relationship between smaller body size and higher occluded-ear EEA, these preliminary results suggest that body size (and occluded-ear EEA; a function of body size) could be a potential, underlying driver of NIHL susceptibility differences, rather than true sex differences.