Abstract
OBJECTIVE: Electrocochleography (ECoG) is a sensitive evoked-response test for evaluating changes in cochlear function. We investigated the extratympanic ECoG in a noise-induced temporary threshold shift (TTS) to evaluate the usefulness of ECoG in the early detection of noise-induced hearing loss (NIHL).
STUDY DESIGN AND METHODS: In a prospective analysis, 15 healthy ears were exposed to 90.3- to 105.0-dB noise for 3 hours in the same computer-game arcade. Pure-tone audiometry and ECoG were performed before, immediately after, and 24 hours after the exposure.
RESULTS: Before the exposure, the average hearing level was 5.8 ± 2.7 dB, which increased significantly to 12.8 ± 2.8 dB immediately after exposure. A marked increment in the SP/AP (summating potential/action potential) ratio was observed with the TTS. The mean ratio was 0.22 ± 0.11 before the exposure, 0.46 ± 0.18 in the TTS phase, and 0.20 ± 0.11 after resolution.
CONCLUSION: The results of this study suggest that the SP/AP ratio is useful for the early detection and monitoring of NIHL. (Otolaryngol Head Neck Surg 2004;130:437–42.)
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