[Cochlear nerve conduction block restoration of hearing after removal of cerebellopontine tumors].

Hearing restoration after removal of cerebellopontine tumors has only infrequently been observed. We present 5 cases with dramatic improvement of both pure tone threshold and speech threshold after excision of tumors. Two patients had acoustic neuroma, 2 meningioma and one cerebellar hemangioblastoma. Preoperatively, the patients suffered severe sensorineural hearing loss and had no measurable speech discrimination score. Recordings of the auditory brain stem response were absent or showed only wave I. However, results of the electrocochleogram were within normal limits. After removal of the tumors, their hearing returned to normal and remained stable thereafter. The data are consistent with the hypothesis that pressure from the tumor causes cochlear nerve conduction block and hearing impairment.