Saunders S S, Salvi R J, Miller K M
Department of Communicative Disorders and Sciences, State University of New York at Buffalo 14214.
J Acoust Soc Am. 1995 Feb;97(2):1150-64. doi: 10.1121/1.412228.
Three adult, female chickens, previously trained to detect pure tones using a positive reinforcement paradigm, were exposed to pure tones at 525 Hz at 120-dB sound-pressure level for 48 h. Immediately after exposure, pure-tone thresholds were elevated between 10 and 56 dB compared to pre-exposure values. The configuration of the initial hearing loss was essentially flat between 500 and 2000 Hz, with slightly less loss at lower and higher frequencies. Over the course of 100 to 600 h, depending on subject and test frequency, thresholds returned to preexposure levels. The slopes of the threshold-duration functions measured shortly after exposure were shallower than normal, but returned to the normal slope of approximately 3 dB per doubling of duration as hearing loss resolved to less than 15 to 20 dB. The cochleas from additional chickens examined by scanning electron microscopy (SEM) and fluorescence microscopy between 0 and 1512 h post-exposure showed extensive damage to the tectorial membrane over the middle two-thirds of the cochlea, with mild to moderate hair cell loss in the region of the cochlea associated with the exposure frequency.
三只成年雌性鸡，此前通过正强化范式训练以检测纯音，将它们暴露于525赫兹、声压级为120分贝的纯音下48小时。暴露后立即测量，与暴露前相比，纯音阈值升高了10至56分贝。初始听力损失的形态在500至2000赫兹之间基本呈平坦状，在较低和较高频率处损失略小。在100至600小时的过程中，根据个体和测试频率不同，阈值恢复到暴露前水平。暴露后不久测量的阈值-时长函数的斜率比正常情况更平缓，但随着听力损失降至15至20分贝以下，斜率恢复到正常的约每时长加倍3分贝。在暴露后0至1512小时之间，通过扫描电子显微镜（SEM）和荧光显微镜检查的其他鸡的耳蜗显示，耳蜗中三分之二区域的盖膜受到广泛损伤，与暴露频率相关的耳蜗区域出现轻度至中度的毛细胞损失。
