What is a cochlear implant? 

A cochlear implant is a small, complex electronic 

device that can help to provide a sense of sound to 

a person who is profoundly deaf or severely hard-ofhearing. The implant consists of an external portion 

that sits behind the ear and a second portion that is 

surgically placed under the skin (see figure).

An implant has the following parts:

• A microphone, which picks up sound from the 

environment.

• A speech processor, which selects and arranges 

sounds picked up by the microphone.

• A transmitter and receiver/stimulator, which receive 

signals from the speech processor and convert them 

into electric impulses.

• An electrode array, which is a group of electrodes 

that collects the impulses from the stimulator and 

sends them to different regions of the

auditory nerve.

An implant does not restore normal hearing. Instead, 

it can give a deaf person a useful representation of 

sounds in the environment and help him or her to 

understand speech.

How does a cochlear implant work? 

A cochlear implant is very different from a hearing 

aid. Hearing aids amplify sounds so they may be 

detected by damaged ears. Cochlear implants bypass 

damaged portions of the ear and directly stimulate the 

auditory nerve. Signals generated by the implant are 

sent by way of the auditory nerve to the brain, which 

recognizes the signals as sound. Hearing through a 

cochlear implant is different from normal hearing and 

takes time to learn or relearn. However, it allows many 

people to recognize warning signals, understand other 

sounds in the environment, and enjoy a conversation 

in person or by telephone.

Transmitter

Receiver/stimulator

Microphone

Electrode

array

Ear with cochlear implant

NIH Medical Arts

Speech

processor

NIDCD Fact Sheet

Cochlear Implants 

u.s. department of health & human services ∙ national institutes of health ∙ National Institute on Deafness and Other Communication Disorders hearing balance
Who gets cochlear implants? 

Children and adults who are deaf or severely hard-ofhearing can be fitted for cochlear implants. According 

to the Food and Drug Administration (FDA), as of April 

2009, approximately 188,000 people worldwide have 

received implants. In the United States, roughly 41,500 

adults and 25,500 children have received them.

Adults who have lost all or most of their hearing later 

in life often can benefit from cochlear implants. They 

learn to associate the signal provided by an implant 

with sounds they remember. This often provides 

recipients with the ability to understand speech solely 

by listening through the implant, without requiring

any visual cues such as those provided by lipreading or 

sign language.

Cochlear implants, coupled with intensive 

postimplantation therapy, can help young children 

to acquire speech, language, and social skills. Most 

children who receive implants are between two and 

six years old. Early implantation provides exposure to 

sounds that can be helpful during the critical period 

when children learn speech and language skills. In 

2000, the FDA lowered the age of eligibility to 12 

months for one type of cochlear implant.

How does someone receive a 

cochlear implant?

Use of a cochlear implant requires both a surgical 

procedure and significant therapy to learn or relearn 

the sense of hearing. Not everyone performs at the 

same level with this device. The decision to receive 

an implant should involve discussions with medical 

specialists, including an experienced cochlear-implant 

surgeon. The process can be expensive. For example, 

a person’s health insurance may cover the expense, 

but not always. Some individuals may choose not 

to have a cochlear implant for a variety of personal 

reasons. Surgical implantations are almost always safe, 

although complications are a risk factor, just as with 

any kind of surgery. An additional consideration is 

learning to interpret the sounds created by an implant. 

This process takes time and practice. Speech-language 

pathologists and audiologists are frequently involved in 

this learning process. Prior to implantation, all of these 

factors need to be considered.

What does the future hold for 

cochlear implants?

With advancements in technology and continued 

follow-up studies with people who already have 

received implants, researchers are evaluating how 

cochlear implants might be used for other types of 

hearing loss.

NIDCD is supporting research to improve upon the 

benefits provided by cochlear implants. It may be 

possible to use a shortened electrode array, inserted 

into a portion of the cochlea, for individuals whose 

hearing loss is limited to the higher frequencies. Other 

studies are exploring ways to make a cochlear implant 

convey the sounds of speech more clearly. Researchers 

also are looking at the potential benefits of pairing 

a cochlear implant in one ear with either another 

cochlear implant or a hearing aid in the other ear.

NIDCD Fact Sheet

Cochlear Implants 

hearingbalance
Where can I find more information?

The NIDCD maintains a directory of organizations 

that provide information on the normal and 

disordered processes of hearing, balance, smell, taste, 

voice, speech, and language. Please see the list of 

organizations at http://ww.nidcd.nih.gov/directory.

Use the following keywords to help you search for 

organizations that can answer questions and provide 

printed or electronic information on cochlear implants:

• Cochlear implants

• Assistive technology

• Assistive listening device 

For more information, additional addresses and phone 

numbers, or a printed list of organizations, contact:

NIDCD Information Clearinghouse

1 Communication Avenue

Bethesda, MD 20892-3456

Toll-free Voice: (800) 241-1044

Toll-free TTY: (800) 241-1055

Fax: (301) 770-8977

E-mail: nidcdinfo@nidcd.nih.gov

Centers for Disease Control and Prevention (CDC)
NIDCD supports and conducts research and research training on the 

normal and disordered processes of hearing, balance, smell, taste, 

voice, speech, and language and provides health information, based 

upon scientific discovery, to the public.

hearing, balancesmell, tastevoice, speech, language

NIDCD Fact Sheet: Cochlear Implants

Publication No. 09-4798

Updated August 2009

For more information, contact:

NIDCD Information Clearinghouse

1 Communication Avenue

Bethesda, MD 20892-3456

Toll-free Voice: (800) 241–1044

Toll-free TTY: (800) 241–1055

Fax: (301) 770–8977

E-mail: nidcdinfo@nidcd.nih.gov

Internet: http://www.nidcd.nih.gov

The NIDCD Information Clearinghouse is a service of the 

National Institute on Deafness and Other Communication 

Disorders, National Institutes of Health, U.S. Department 

of Health and Human Services.