Analysis Of Evoked Otoacoustic Emission In Normal Pure Tone Hearing Thresholds Patients With Aural Fullness

ObjectiveSensorineural hearing loss is often irreversible. It is difficult to recover once hearing loss appear. So early detection of the disease, early diagnosis and early intervention before the appearance of hearing loss is particularly important. With this purpose, we investigated normal pure tone hearing threshold patients with aural fullness who had excluded the lesions of the external ear, middle ear and facial nerve lesions. And we explored whether otoacoustic emission (OAE) is normal in these patients in order to detect the early cochlear impairment.MethodsWe selected 43 patients (72 ears) with normal pure tone hearing thresholds as aural fullness group. These patients were only with the chief complaint of ear fullness, ear fullness sensation or pressure and without tinnitus, vertigo and other accompany symptoms. The patients with the external ear, middle ear and facial nerve disorders were excluded. And 30 healthy subjects (60 ears) were served as control group. Transiently evoked otoacoustic emission (TEOAE) and distortion product otoacoustic emission (DPOAE) were tested with Capella otoacoustic emission machine which was made in Denmark Madsen company. The DPOAE detection rate and amplitudes at all frequencies, the passing rate and wave signal noise ratio (SNR),wave reproducibility, band SNR and band reproducibility of TEOAE were recorded. SPSS15.0 statistical software was used for statistical analysis.Results1.The detection rate of DPOAE was 100% from 4kHz to 8kHz in both aural fullness group and control group. Only on the frequency points of 0.5kHz,0.75 kHz and 1.0 kHz,the detection rate of DPOAE in aural fullness group was lower than that in control group(P<0.05).There was no significant difference in the rate among other frequency points(P>0.05).2.Compared with the control group, the DPOAE amplitudes at 0.5 kHz,0.75 kHz, 1.0 kHz,1.5 kHz,2.0 kHz,3.0 kHz,4.0 kHz,6.0 kHz,8.0 kHz of the aural fullness group were significantly decreased. There were statistical differences(P<0.01).3.The passing rate of TEOAE was 100%(60/60)in control group and 90.28% (65/72) in aural fullness group. There were statistical differences between two groups(x2=6.16,P<0.05).4.The wave reproducibility and band reproducibility in 0.75～1.25 kHz,1.25～1.75 kHz,1.75～2.50 kHz,2.50～3.50 kHz,3.50～4.50kHz of TEOAE in aural fullness group were lower than that in control group(P<0.05或P<0.01).There were statistical differences.5.The wave signal noise ratio (SNR) and band SNR in 0.75～1.25 kHz,1.25～1.75 kHz,1.75～2.50 kHz,2.50～3.50 kHz,3.50～4.50kHz of TEOAE in aural fullness group were lower than that in control group(P<0.01).There were statistical differences. Conclusions1.Normal pure tone hearing thresholds patients with aural fullness are very common in clinical.We can not firmly believe that the hearing function was normal in these patients because of their normal pure tone hearing thresholds.2.The passing rate of TEOAE, reproducibility, SNR, the detection rate of DPOAE and the DPOAE amplitudes were lower than the control group in aural fullness patients.Some patients of normal hearing thresholds with aural fullness have had early harmness of outer hair cell in cochlear.OAE may be used to detect these lesions early before the hearing impairment occurred.3.For this part of normal pure tone hearing thresholds patients with aural fullness we must focus on health education. We should tell them far away from the noise, to refuse ototoxic drugs, to develop good sleeping habits and lifestyle.They should be long-term follow-up.And we must pay close attention to their hearing status.4.OAE is a rapid, noninvasive and objective hearing test.It can detect the status of outer hair cells in inner ear sensitively. It has greater advantage than pure tone audiometry, especially in the early detection of cochlear lesions.