Cochlear implant

A cochlear implant is a device designed to provide useful sound sensations to some people with severe or profound hearing loss. It is distinct from a hearing aid: hearing aids amplify sound, whereas a cochlear implant converts sound into electrical signals that stimulate the auditory nerve, bypassing damaged portions of the ear. The brain learns to interpret those signals as sound, but the result is not the same as normal hearing.

A typical system includes an external microphone, sound processor and transmitter, along with an implanted receiver-stimulator and an electrode array placed in the inner ear. The microphone picks up environmental sound; the processor selects and organizes it; and the external transmitter sends coded signals to the implanted component. The electrode array delivers electrical impulses that stimulate auditory nerve pathways. The brain then interprets the resulting signals.

Candidacy and expected benefit depend on an individual's hearing, medical circumstances and other factors. Assessment involves hearing professionals and medical specialists; a cochlear-implant team can discuss whether implantation is appropriate. Implantation requires surgery, followed by device fitting and ongoing auditory rehabilitation or training. Learning to interpret the implant's signals takes time, and outcomes differ between individuals. The decision involves the person or, for a child, their family and clinical team.

For some recipients, an implant can improve access to environmental sounds and speech understanding, including in situations where hearing aids provide limited benefit. The amount and type of benefit are not predictable for every individual, and an implant does not guarantee speech understanding or restore natural hearing. Some people may retain or develop useful abilities in combination with other communication approaches; device use does not replace an individual's preferred language or communication choices.

As with other operations, implantation has surgical and anesthesia risks. The U.S. Food and Drug Administration lists possible complications including infection, dizziness, tinnitus, injury to nearby nerves, and loss of residual hearing in the implanted ear. Device failure or other complications may require further care. Implant users also need to consider device-specific guidance for medical procedures, water, impacts and maintenance. Risks and precautions vary by person and device, so they should be discussed with qualified clinicians and the implant manufacturer.