cochlear implant
an electronic device designed to enable individuals with complete deafness to hear and interpret some sounds, particularly those associated with speech. It consists of a microphone to detect sound, a headpiece to transmit sound, a processor to digitize sound, and a receiver to signal electrodes that are surgically implanted in the cochlea to stimulate the auditory nerve. In contrast to a hearing aid, which amplifies sound, it directly stimulates the auditory nerve.