Monitoring by ABR, TEOAE and DPOAE of Noise Induced Hearing Loss in Guinea Pig / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Noise-induced hearing loss (NIHL) is associated with the damage in outer hair cell (OHC). Otoacoustic emmision (OAE) is sensitive to the detection of damage in OHC. We intended to evaluate the usefulness of transient evoked OAE (TEOAE) and distortion product OAE (DPOAE) on early detection and monitoring of NIHL in guinea pigs. MATERIALS AND METHODS: Ten healthy guinea pigs were exposed to 90+/-3 dBA white noise 8 hours daily for 9 days. Daily measurements of auditory brainstem response (ABR), TEOAE and DPOAE were performed before the noise exposure and daily after the noise exposure. RESULTS: ABR threshold became poorer gradually until the 8th day of post noise exposure, and some recovery on the 9th day. Wave reproducibility on TEOAE demonstrated an abrupt decrement on the 6th post-exposure day, and a tendency of recovery from the 7th day. While the echo amplitudes in f2=2002 Hz and f2=4004 Hz showed similar pattern of change with ABR threshold, the echo amplitude of f2=6348 Hz showed marked decrease on the 5th day compared to two other frequencies (f2=2002 Hz, 4004 Hz). CONCLUSION: The results of this study suggest that wave reproducibility in TEOAE and echo amplitude in high frequency in DPOAE may have applicability for early detection and monitoring of NIHL.