Histopathological analysis of a 15-year user of an auditory brainstem implant.

Auditory brainstem implants (ABIs) can provide highly beneficial hearing sensations to individuals deafened by bilateral vestibular schwannomas (neurofibromatosis type 2). Relatively little is known about the status of stimulated neurons after long-term ABI use. Direct examination of the cochlear nuclear complex (CN) of one 5-year ABI user indicated no deleterious effect. Recently, we examined the brainstem of a patient who used his ABI daily for 15 years with excellent performance. There was good preservation of CN cell size, morphology, and packing density, a very favorable sign considering that a number of infants are now receiving ABIs.