How many people have received a cochlear implant?

Cochlear implants were first approved by the Food and Drug Administration in the United States in 1985 for adults and in 1990 for children. Today, over 20,000 individuals have received cochlear implants, including over 8,000 children.

General Criteria
(for Pedriatric population) Profound sensorineural hearing loss (nerve deafness) in both ears 12 months through 17 years of age

Little or no useful benefit from hearing or vibrotactile aids

No medical contraindications

High motivation and appropriate expectations by child and parents/guardians

An educational/rehabilitation program that emphasizes development of auditory skills

What is a Cochlear Implant?
A cochlear implant is a small electronic device that provides a sense of sound to children and adults who have severe to profound hearing loss and who cannot hear and/or understand speech with hearing aids. Hearing aids make sound louder. Cochlear implants do not amplify sound, but rather bypass the outer, middle, and inner ear and directly stimulate auditory nerve fibers.

The cochlear implant is an important option for a child with profound deafness who does not receive significant benefit from hearing aids or other devices. A cochlear implant is an electronic device to provide auditory information by directly stimulating the surviving auditory nerve fibers in the inner ear.

The cochlear implant system consists of two parts:

• an internal device which is surgically implanted into the inner ear and,
• an external component consisting of a head set and speech
  processor which is programmed individually to supply sound to a child.
  
  
  

• Some children can identify everyday sounds, such as car horns, doorbells and birds singing, from a set of alternatives.
  
• Many children can distinguish among different speech patterns.
  
• Many children can identify words from a set of alternatives without lipreading
  
• Some children exhibit improved lipreading
  
• A few children can recognize speech without lipreading
  
• After training and experience with the device, many children demonstrate improvements in speech production and perception
  
  
  

What is normal hearing?
For people with normal hearing, sound travels from the outer ear into the ear canal and causes the eardrum to vibrate. The eardrum is attached to three small bones in the middle ear that begin to move and carry the vibration from the eardrum to a fluid-filled part of the inner ear called the cochlea. Movement in the fluid within the cochlea causes hair fibers (or hair cells) in the cochlea to move. The movement of these hair cells triggers a chemical reaction, which stimulates the hearing nerve. Then, the nerve sends the information to the brain, where it is recognized as sound.

For people with normal hearing, sound travels from the outer ear into the ear canal and causes the eardrum to vibrate. The eardrum is attached to three small bones in the middle ear that begin to move and carry the vibration from the eardrum to a fluid-filled part of the inner ear called the cochlea. Movement in the fluid within the cochlea causes hair fibers (or hair cells) in the cochlea to move. The movement of these hair cells triggers a chemical reaction, which stimulates the hearing nerve. Then, the nerve sends the information to the brain, where it is recognized as sound.

What does the cochlear implant look like and where is it placed?

A cochlear implant consists of three parts: receiver/stimulator, headpiece, and speech processor.

1.   Receiver/Stimulator. The receiver/stimulator is the part that is implanted. It looks like a magnetic disk about the size of a poker chip. It is placed under the skin behind one ear. A wire leads from the receiver/stimulator to an array of electrodes, which is fed into the cochlea in the inner ear. Surgery to implant the receiver may be done as an outpatient or may require a short hospital stay. It is performed by otolaryngologists (ear, nose, and throat physician) who specialize in implantation. The surgery usually takes between 2 and 3 hours but may last as long as 5 hours and may require an overnight stay in the hospital.

2.   Headpiece. A small headpiece is worn just behind the ear and contains the microphone and transmitter. The microphone picks up sound in the environment and the transmitter sends the processed sound to the internal system. The transmitter is held in place over the implanted receiver/stimulator by small magnets in both the transmitter and the implanted device.

3.   Speech processor. The speech processor changes the acoustic sound into electrical information. The processor may be worn completely behind the ear or on the body in a harness or on a belt. It is attached to the transmitter and microphone by special cords.

What happens after the implant is in place?
Once in place, the implant system works as follows. Sound waves enter the microphone located in the headpiece. Sound is sent through a cord to the speech processor. The speech processor converts the sound into a special electrical signal that is sent up a cord to the transmitter. The transmitter then sends the information across the skin flap to the receiver/stimulator, which in turn sends the signal to the electrode array in the cochlea. The auditory or hearing nerve is stimulated and the information is sent to the brain and interpreted as sound.

The speech processor of the cochlear implant system should be adjusted periodically. These programming sessions or "MAPpings" occur more frequently during the first months of implant use. Fewer, less frequent visits are needed as the implant user becomes more accustomed to their device and proficient at participating in programming. The time involved to complete the MAPping of the speech processor varies among users and cochlear implant systems, but will generally take 1 to 2 hours. Cochlear implant users should return to the clinic at least once a year for adjustments of the speech processor.

Will training be needed on how to use the implant?
Both children and adults who utilize cochlear implants can benefit from training or aural habilitation. This specialized training teaches them how to use their cochlear implant system. Working with audiologists, speech-language pathologists, and teachers of the hearing impaired will help with alerting to and identifying environmental and speech sounds, discriminating and understanding speech, and producing speech sounds appropriate for their listening age. Instruction for practicing at home is also key. For children, habilitation and education are gravely important since most children who receive cochlear implants are already language delayed. The goal for many children is to develop vocabulary and language to match that of their normal hearing peers.

What can I expect from a cochlear implant?
Cochlear implants do not provide normal hearing - they provide an improvement in the use of sound. With a cochlear implant, profoundly hearing impaired people are able to detect even very soft sounds. Their range of hearing includes speech at comfortable listening levels. Most can learn to recognize familiar sounds. For some, cochlear implants aid in communication by improving the person's ability to understand what is being said. Much of the success depends upon the individual person's ability to adapt to the new sound produced by the implant system and their motivation to hear and communicate.

In addition, results will vary depending on age at the time of deafness, age at the time of surgery, how long the person has been deaf, previously acquired speech/language skills, residual hearing or the condition of the nerve fibers. Prior to surgery, the cochlear implant team will explain what is reasonable to expect for each person.

Learning to Use the New Sound
Hearing speech with the implant may sound unnatural at first. However, over a period of time, the sounds will become familiar. People who have never heard may require a longer time period to adjust to the new sounds.

Both children and adults benefit from supportive services that teach them how to use their cochlear implant. Working with an audiologist, speech-language pathologist, or teacher of the hearing-impaired will help the person identify environmental sounds and discriminate among speech sounds. Therapy and training also will focus on helping the person develop language and speak more clearly. Instruction will be given for practicing at home.

After the implant, therapy for children is essential; without it, a child will obtain only partial benefit from the device because it merely makes new sounds available. The child must be taught how to understand the new sounds and translate them into improved speech and language. Children must learn to associate meaning with unfamiliar sounds. Auditory, speech production, and language services can be provided by staff at the child's school. These services will be required for an extended period of time, often throughout childhood. A child's performance will usually continue to improve over time with training.

In addition to school intervention, it is strongly recommended that children receive aural habilitation privately through a speech/language pathologist who specializes in cochlear implants.

After the Surgery: Learning to Hear With a Cochlear Implant

Fitting and Mapping

A recovery time of 3 to 5 weeks is necessary between the time of surgery and the initial fitting of the external equipment. This allows the incision to heal and any swelling to subside. The headpiece is fitted during a return visit to the implant center. During this visit, instruction is given in the care and maintenance of the system and on how to obtain training in listening to sound through the implant.

The initial stimulation with a cochlear implant occurs through programming computers. The speech processor is connected to the computer. Threshold levels and louder, yet comfortable levels will be set for each electrode channel of the device. The various channels have different frequencies allocated to them and will sound different in pitch.

First, the patient is asked to listen and respond to the sensation of very soft beeps. Later, when setting the louder levels, the patient is asked to indicate when the sound becomes comfortably loud. This will create a range of hearing from soft to medium to loud sounds for the implant user. Then, a MAP (program) is created and downloaded into the patient’s speech processor. The user’s microphone may be turned on and the user will be able to hear speech and environmental sounds through their cochlear implant system.

Rechargeable or disposable batteries are inserted into the speech processor, and the implant system can be taken home. The time involved to complete the programming of the speech processor varies among users and cochlear implant systems, but typically requires between 1 and 2 hours. During the first months of implant use, as the patient acclimates to this different way of hearing, reprogramming is performed often; thereafter, fewer visits are required. Visits to the clinic should be scheduled at least once a year for program adjustments of the speech processor.

Is the implant done in both ears?
YES.
More and more "bilateral" surgeries are beening performed. The success rate on these individuals is still being researched.

Expectations
Before children with normal hearing learn to speak, they spend over a year listening to sounds around them. Even after listening for one year, children do not speak perfectly when they begin. The same is true for newly implanted children. These children may not recognize their name or say their first intelligible word for 6 to 12 months. Be patient and go from the simple to the complex when working with the new cochlear implant user. Talk to the child normally and read, sing, and enjoy picture books together. Children's stories on tape, accompanied by follow-along books, are good for older children and adults to assist them in learning the sounds and rhythms of speech. Television and radio and exposure to speech in all settings, starting with one person in a quiet setting and working up to groups and settings with background noise, are helpful and can provide opportunities to practice hearing. Expect the cochlear implant to provide useful sound and improved hearing with practice and patience.

Who is a candidate for a cochlear implant?

Adults and children can benefit from a cochlear implant if they meet the following criteria:

Adults (18 years of age and older)

Severe to profound hearing loss in both ears
Limited benefit from hearing aids
No medical contraindications
A strong desire to be part of the hearing world

Children (12 months of age to 17 years of age)

Profound hearing loss in both ears
Little or no useful benefit from hearing aids
No medical contraindications
High motivation and appropriate expectations (both child and family)
Placement in an educational program that emphasizes development of auditory skills
after implantation

An evaluation will be performed at the implant center to determine if a person is an appropriate candidate for a cochlear implant. Some of the tests that may be performed include an otologic evaluation, a hearing evaluation with a hearing aid trial period, a psychological evaluation, a speech/language evaluation, a CT or MRI to check the structure of the inner ear, and a physical examination.