Cochlear implantation is an established habilitative and rehabilitative option for profoundly deafened individuals over 1 year of age who derive limited benefit from conventional hearing aids. Auditory performance varies among individuals and is determined primarily by age at implantation, pre-existence of speech and language skills, and the time interval between onset of deafness and implantation. Successful implant users generally demonstrate improved auditory abilities and speech production skills beyond those achieved with hearing aids. Multichannel ABIs can provide useful auditory information to patients with NF-2 who have lost integrity of auditory nerves following removal of vestibular schwannomas. The implant allows for awareness of environmental sounds and, potentially, speech recognition. Most patients undergoing implantation demonstrate improved lip-reading skills, and exceptional performers achieve understanding of open-set speech.