Clinical value of distortion product otoacoustic emission in tinnitus patients with normal hearing

Objective To investigate the clinical value of distortion product otoacoustic emission(DPOAE) application in normal hearing patients with tinnitus.Methods A total of 82 healthy volunteers(164 ears) without tinnitus or hearing loss were enrolled as control group and tested with DPOAE.Meanwhile,84 normal hearing patients(109 ears) with tinnitus were tested with DPOAE before and after 20-days treatment including circulation improvement and supplemental nutrition for inner ear.Results At the frequency of 0.5,0.75,1.00,1.50,2.00,3.00,4.00,6.00 and 8.00 kHz,the detection rate of DPOAE in tinnitus group was significantly lower than that in control group(all P0.05).In tinnitus group,the difference of DPOAE detection rates before and after treatment had no statistical significance(56.9% vs.43.1%,P0.05);the wave height in every frequency was increased after treatment,especially in high frequency(3.00,4.00,6.00 and 8.00 kHz,all P0.05).Conclusion Tinnitus with normal hearing is likely to be related to hearing loss of super high frequency caused by early impairment of outer hair cells in cochlea.DPOAE examination can be used as an objective assessment for early change of cochlea and periphery tinnitus.