[Auditory neuropathy].

OBJECTIVE

To explore the clinical and auditory functional feature of auditory neuropathy(AN).

METHOD: The clinic signs, audiometric test and electrophysiology were analyzed on 54 cases of AN.

RESULT: 70 ears had low frequency pure tone hearing loss. 24 ears had cover basic hearing threshold. 6 ears had flat hearing threshold. 4 ears showed high frequency hearing loss. The average low-frequency, median-frequency and high-frequency hearing threshold were 67.63 +/- 15.30, 43.61 +/- 16.28 and 32.25 +/- 14.80 dB HL respectively. The tympanograms are normal. 77 ears lost acoustic reflex. 31 ears increased acoustic reflex threshold. All of them induced no ABR and had normal DPOAE with 26 cases' contralateral acoustic suppression uninfluenced. 16 cases had controversial pure tone threshold compared with speech discrimination. 23 had normal temporal bone CT image or MRI. 10 cases accompanied with peripheral neuropathy.

CONCLUSION

Abnormal ABR, normal DPOAE, unparallel pure tone threshold to speech audiometry, loss of stapedial acoustic reflex and OAE contralateral acoustic suppression, loss of the pure tone threshold primarily in low-frequency SNHL are the important features of AN, which shows that the lesioned site may lie at the intracochlear acoustic nerve. It is necessary to differentiate it from the common SNHL and central nerve hearing loss.