聴神経鞘腫症例における誘発耳音響放射

抄録

Evoked otoacoustic emission (EOAE), auditory brainstem response (ABR) and electrochochleography (Ecoch G) were recorded in3patients with acoustic neurinoma. In all cases EOAE was detectable, despiteof the hearing threshold exceeded 60dB HL, where the occurrence of EOAE usually fall to zero except forcases with fluctuant hearing loss cases i. e. sudden deafness and Meniere's disease. But, ABR was notdetected in any case. EcochG also revealed that the cochlear nerve was damaged in all cases. Theseresults lead us to the assumption that outer hair cells may be preserved in cases of acoustic neurinoma, evenwith severe hearing loss.