Cochlear implants are electronic devices that provide a sound information to the brain, transforming acoustic signals into electrical signals that stimulate the auditory nerve. This prosthesis replaces the function of the damaged portions of the middle ear (cochlea). It consists of two parts: an internal that is placed in the skull by surgery and external that sits behind the ear. Implants are indicated for people who have damaged hair cells in the cochlea and, while not re-establish normal hearing can help deaf or severely hard of hearing people to understand speech. Both children and adults can benefit from cochlear implants. In any case, the patient should follow a rehabilitation speech therapy after placement of the device.