[The influence of short-term pure tone exposure on amplitude of distortion-product otoacoustic emissions and spectral history].

OBJECTIVE: To observe the changs of the amplitude and the spectral history of DPOAE in the slightly damaged cochlea. METHOD: Fifteen of young person with normal hearing were exposed to 4 kHz short-term pure tone (Level = 130 dB SPL) for 3 minutes to analysis the change of DPOAE in details after Temporary Threshold Shift (TTS). RESULT: The comparison of pre- and postexposure showed that the thresholds of sound reflex is 9.78 +/- 6.98, 8.04 +/- 5.58, 13.0 +/- 5.58 dB HL and 8.82 +/- 6.23, 5.75 +/- 4.42, 9.05 +/- 2.27 dB HL in 0.5, 1, 2 kHz, respectively. The amplitude of DPOAE decreased 4.28 dB SPL in 6 kHz, and the spectral history rippled significantly. The coefficience of variance is 5.18 +/- 1.63%. The combination of the amplitude and the coefficience of variance indicated that 80.0% of those is abnormal. CONCLUSION: The results confirmed that the spectral history of DPOAE is a sensible tool to assess the slightly cochlear lesion together with the amplitude of DPOAE.