Background and Objectives : Early detection and monitoring are the most important measures in the prevention of development and progression of noise-induced hearing loss (NIHL). Electrocochleography (ECoG) is known as a sensitive evoked-response
test to
evaluate changes in cochlear function. Through the investigation about the changes of ECoG in development of noise-induced temporary threshold shift (NITTS), we intended to evaluate the usefulness of ECoG on early detection of NIHL. Materials and
Methods : Ten healthy adult participants (20 ears) were exposed to 90.3∼105.0 dB broad-band noise for 3 hours in a computer-game room. Pure-tone audiometry (PTA) and ECoG were performed before the exposure, immediately after and 24 hours after
the
exposure. Results : Before the exposure, mean PTA threshold was 6.1±2.6 dB, which was significantly increased to 12.0±3.2 dB immediately after the exposure, and recovered to 5.5±2.4 dB at 24 hours later. Marked increment of SP/AP (summating
potential/action potential) ratio was observed simultaneously with the development of TTS and was normalized after its resolution. The mean ratio was 0.23±0.17 before the exposure, 0.43±0.16 on TTS phase, and 0.24±0.18 on resolution.
Conclusion
: The
result of this study suggest that SP/AP ratio of ECoG might have applicability for early detection and monitoring of NIHL.
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