[Functional and morphologic changes in inner ear after experimental rupture of the round window membrane in the...

The round window membrane of the guinea pig was perforated with a sharp instrument, and electrocochleography, vestibular function and histological changes of cochlea were studied in 1, 2, 4, 7, 14 and 28 days. It was found that the compound action potential (AP) threshold and the latency increased at 95 dB (spl) sound stimulus, and vestibular function decreased slightly, but histologic appearance of Corti's organ was normal in the early stage. Latency and threshold of AP and vestibular function gradually recovered to normal 2 weeks later. If no obvious histological change took place in inner ear, hearing loss would not appear. There was no significant difference of SP changes between the experimental and control ears.