Perceptive deafness may result from a deficiency in the inner ear or may be neural in origin. In both cases, the transmission of information via the eardrum and the ossicles to the inner ear is perfect. Cochlear perceptive deafness occurs when part of the sensory cells of the inner ear is deficient. The cochlea can no longer transform the sound information that it receives from the middle ear into nerve impulses, which are then transported along the auditory nerve to the brain.   Retrocochlear perceptive deafness is when the auditory nerve is damaged. The inner ear processes the information correctly in the inner ear, but the auditory nerve is incapable of transmitting the nerve impulses to the brain. The origin of perceptive deafness may have a number of causes such as presbyacusis (normal ageing of the inner ear), ear or head injuries, certain illnesses (meningitis)... Perceptive deafness is usually for life. It is not possible to turn to medical or surgical treatment. However, the use of a hearing aid is indicated for many people suffering from mild to severe perceptive deafness. If profound perceptive deafness cannot be treated with a hearing aid to obtain sufficient intelligibility, a cochlear implant is recommended. If the auditory nerve is no longer functioning, the benefits brought by a cochlear implant are not sufficient. In certain cases a brainstem implant may be considered.