Functional and histological findings in acoustic neuroma

27 patients with acoustic neuroma were operated on by translabyrinthine tumor removal. At operation 8th nerve compartments were identified and removed for study. Results of the audiological test battery and vestibular tests were compared with histological state of the nerve specimens studied. The tumor appears only seldom to invade the cochlear nerve in cases with 'cochlear' hearing loss, but in the majority of cases with 'retrocochlear' hearing loss the cochlear nerve is invaded.