Cochlear implants are auditory prostheses designed to stimulate electrically the remaining population of eighth-nerve neurons in the cochlea of profoundly deaf persons.1 Surgical implantation of cochlear prostheses into the inner ear region of deaf patients has moved forward rapidly during the past two years, and, at present, about 500 patients have undergone this procedure. In the simplest terms, the external and implanted components function as a miniaturized transducer that converts sound into an electrical output that stimulates the auditory nerve. The signal is perceived centrally in the brain as a sound that varies with each environmental noise or spoken word. The device helps most adult patients, in that distinguishing environmental sounds and lip-reading ability are improved greatly. The role of cochlear prosthesis implantation in children is less well known and is controversial because of ethical considerations. The implantation procedure is not especially difficult, and the complication rate is low.
Bailey BJ. Cochlear Prosthesis Implantation: Review of the Issues. JAMA. 1984;251(24):3282. doi:10.1001/jama.1984.03340480064031