Borg E
Hear Res. 1983 Mar;9(3):247-54. doi: 10.1016/0378-5955(83)90029-1.
The possibility that a delayed onset hearing loss may occur after noise exposure was investigated in 20 normotensive (N) and 20 spontaneously hypertensive (SH) Wistar rats. Half of the rats of each strain were first exposed to noise at 3 months of age and half were first exposed at 12 months of age. All rats were exposed for a total of 3 months to a noise of 100 dB Leq (lin) (a narrowband noise, sweeping from 3 to 30 kHz at a rate of 0.5 Hz). Hearing thresholds were determined with a behavioral technique, and also on certain selected animals by brainstem audiometry, using pulses of 1/3-octave filtered sine waves. One to two weeks after exposure to noise animals had a 30-50 dB hearing loss. The hearing loss remained stable or progressed only slightly in normotensive animals up to 12 months after end of exposure. Generally the SH animals suffered a slight additional loss of hearing over the 12 months after noise exposure. When tested at 18 months of age 3 of the 10 SH rats exposed to noise from 12 to 15 months of age suffered a hearing loss which covered the whole range of observed frequencies from 1.5 to 44 kHz and which had progressed noticeably. These results suggest that while the delayed effects of noise are normally small, exposure might trigger a pronounced hearing loss in subjects with fragile ears.
在20只血压正常（N）的Wistar大鼠和20只自发性高血压（SH）的Wistar大鼠中，研究了噪声暴露后可能出现迟发性听力损失的可能性。每种品系的大鼠中有一半在3个月大时首次暴露于噪声中，另一半在12个月大时首次暴露。所有大鼠总共3个月暴露于100 dB Leq（线性）的噪声中（一种窄带噪声，以0.5 Hz的速率从3 kHz扫频到30 kHz）。使用行为技术测定听力阈值，并且对某些选定的动物通过脑干听力测定法，使用1/3倍频程滤波正弦波脉冲来测定。暴露于噪声后一到两周，动物出现30 - 50 dB的听力损失。在血压正常的动物中，直至暴露结束后12个月，听力损失保持稳定或仅略有进展。一般来说，SH动物在噪声暴露后的12个月内听力略有额外损失。当在18个月大时进行测试时，10只在12至15个月大时暴露于噪声的SH大鼠中有3只出现了听力损失，其涵盖了从1.5至44 kHz的整个观察频率范围，并且有明显进展。这些结果表明，虽然噪声的延迟效应通常较小，但暴露可能会在耳朵脆弱的受试者中引发明显的听力损失。
