Electrical stimulation of the auditory brain stem structure in deafened adults.

Electrical stimulation of the cochlear nuclear complex in the brain stem was first accomplished in a female adult deafened by bilateral acoustic tumors. The central electroauditory prosthesis (CEP) was surgically placed at the time of the second tumor removal. The patient has now been receiving electrical stimulation for 5 years. Six more adults have received the CEP at the time of tumor surgery. Clinical results indicate fluctuations in electrical measurements over time, particularly in the first weeks following surgery. Patients are able to sustain tone perception for one minute at all frequencies tested. Auditory discrimination test results reveal above-chance performance on suprasegmental measures, similar to scores achieved by cochlear implant users. No serious complications have occurred to date.