[Sudden hearing loss in acoustic neuroma]

To avoid misdiagnosis and mistherapy of acoustic neuroma, 104 cases of acoustic neuroma treated between 1986 and 1995 were retrospectively reviewed. Among them, 23 patients (24 ears, 23%) presented with sudden hearing loss as the starting symptoms. The clinical and audiological analysis demonstrated that 54.2% of the ears showed hearing loss over 71 dB HL, and all ears had deteriorated ABRs. -SP/AP was measured in nine ears, seven showed -SP/AP greater than 0.4. Acoustic reflex was negative in all 11 ears tested, and 94.4% of the ears showed abnormal ENG. The rate of positive CT scan was 88.8%. The diagnosis was made with CT pneumo-encephalography or MRI in those with negative CT result. It was concluded that for patients with sudden deafness, ABR should be used as a routine test. When ABR was abnormal, CT scan of the internal auditory meatus was needed.