[Compensation of the inner ear exposed to stabile noises of different intensities].
The dynamic changes of AP to click stimuli. the values of the static EP and the cochlear ultrastructures of the albino guinea pigs after exposure to stabile noise of three intensities (115dBA, 125dBA, 130dBA) for 4 hours were observed. At 115dBA, EP did not change; the threshold of AP was 46 +/- 6dBHL, which returned to normal 3 days after exposure. At 125dBA, EP increased to 91.6 +/- 6.9mv, and took 3 days to recover; AP was 64 +/- 3dBHL, and recovered completely in 14 days. At 130dBA, EP decreased to 68.7 +/- 19.3 mv, spending 7 days to resume; AP was 68.5 +/- 4.7dBHL, not returned to control level during 14 days. The cochlear impairment aggravated with intensified noise level, and did not improve as EP and AP recovered. At 130dBA, there were several minor holes and fractures in the reticular lamina. These results indicate that the different intensities of noises cause different conditions of noise-induced inner ear injury. The inner ear has a peculiar compensation mechanism to resume stability.
Hu
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N
Navy General Hospital, Beijing.
D000200:Action Potentials; D000818:Animals; D001309:Auditory Threshold; D003051:Cochlea / Q000473:pathology / Q000503:physiopathology*; D004594:Electrophysiology; D006168:Guinea Pigs; D006317:Hearing Loss, Noise-Induced / Q000503:physiopathology*; D008297:Male