P125: EMG in Patients with Chronic Unilateral Tubal Dysfunction

Abstract

Distortion product otoaconstic emission (DPOAE) was compared with auditory brain-stem response (ABR) in the early diagnosis of gentamicin (GM) ototoxicity, to determine whether impaired hearing could be improved with the glutathione treatment after its withdrawl of injection. METHODS: Forty guinea pigs with normal hearing were randomly divided into four groups, 10 in DPOAE group, 12 in ABR I group (the usage of GM was stopped when abnormal shift presented in ABR), 12 in ABR II (group glutathione was injected for 5 after the usage of GM had been stopped), 6 in the control group. The guines pigs in experimental group were injected with GM 100mg/kg per day, while those in the control group were injected with saline. The DPOAE and ABR were monitored to observe the amplitude and the threshold of wave IV. The morphological changes of hair cells were also observed after injection of GM had been stopped for two weeks. RESULTS: It averaged at 7d after the injection of GM when the changes presented in DPOAE group, while 10d in ABR group. The threshold shift increased after the injection had been stopped for two weeks in ABR I group (PϽ0.01), while there was no obvious shift in ABR II group. The morphological and functional changes of the hair cells were almost the same. CONCLUSIONS: GM ototoxicity could be more sensitively observed by DPOAE than ABR. Glutathione could prevent further ototoxic effect of GM to the cochlear.