THE MULTICHANNEL AUDITORY BRAIN-STEM IMPLANT - PERFORMANCE IN 20 PATIENTS

The auditory brain stem implant has been used effectively to provide h earing sensations to individuals deafened by bilateral auditory nerve tumors (neurofibromatosis type 2). During tumor removal, the auditory brain stem implant is implanted into the lateral recess of the fourth ventricle by a translabyrinthine approach and is intended to stimulate auditory neurons of the cochlear nucleus complex. A new eight-electro de multichannel auditory brain stem implant was developed and evaluate d in 20 patients who had at least 3 months' experience with the device , Mild nonauditory sensations (primarily tingling in the head or torso ) were encountered in some instances but could be managed by changing the stimulus characteristics or excluding electrodes. Testing of perce ptual performance indicated significant benefit from the device for co mmunication purposes, including sound-only sentence recognition scores in three patients ranging from 49% to 58% and ability to converse on the telephone. These results indicate that significant auditory benefi t can be derived from direct multichannel electrical stimulation of th e auditory portion of the human brain stem.