Application of distortion product otoacoustic emission to hearing investigation in the ship crew

Abstract

Objective To explore the application of the distortion product otoacoustic emission (DPOAE) in the diagnosis of noise-induced hearing damage for the ship crew.Methods The experimental group consisted of 100 crew members,among whom 52 had noise-induced hearing damage and 48 people had normal hearing thresholds.And another 50 people with normal hearing level were chosen as control.The two groups received acoustic emission,pure tone audiometry and DPOAE testing.Hearing thresholds,DPOAE amplitude and the provocation rate were compared between the two groups.Results Statistical differences could be noted in hearing thresholds in all frequency zones,when a comparison was made between the noise-induced hearing damage group and the control group ( P < 0.05 ).DPOAE amplitude and the provocation rate of the experimental group decreased significantly ( P < 0.05 ),when compared with those of the control group.With the extension of noise exposure,DPOAE provocation rate for the ship crew decreased ( P < 0.05 ).DPOAE amplitude and the provocation rate of the normal hearing level group also decreased more significantly than those of the control group (P < 0.05 ).Conclusions Pure-tone hearing threshold for the ship crew with early noise-induced hearing damage might be normal.DPOAE could be applied to early diagnosis and appraisal of early noise-induced hearing damage. Key words: Distortion product otoacoustic emissions; Pure tone audiometry; Ship crew; Noise-induced hearing damage