Cochlear Implants

Cochlear implants are not appropriate for everybody with hearing loss. But for those who meet the criteria for the procedure, these small electronic devices can be very beneficial.

Among children and adults with severe, irreversible hearing loss, even the most powerful hearing aids offer little on no improvement. For many, cochlear implants may be able to deliver what hearing aids cannot: an opportunity to hear, and all the benefits that come with it.

What are Cochlear Implants?

Cochlear implants are small, sophisticated electronic devices that are surgically implanted behind the ear. They’re designed to produce useful hearing sensations by stimulating auditory nerves and compensating for parts of the inner ear that either are damaged or don’t work at all.

How Cochlear Implants Work

A cochlear implant consists of an external microphone and speech processor that receive and convert sound waves into electrical signals. The signals are transmitted over a small cable to one or more electrodes that are implanted in the cochlea. These impulses are then sent to the brain, where it is recognized as sound.

Benefits of Cochlear Implants

While cochlear implants won’t give you perfect hearing, some people who have the procedure may regain near-normal hearing. A small percentage of people who get implants notice minimal benefit. Most can expect to acquire useful hearing ability that falls somewhere between the two extremes.

  • Post-lingually deafened adults often benefit immediately and continue to dramatically improve for about 6 months after the initial tuning sessions. Hearing performance continues to improve for several years, at a slower rate.
  • Children may benefit at a slower pace. Considerable training is needed after implantation to help a child use the new 'hearing' he or she now experiences.

Many people who receive cochlear implants gain the ability to:

  • Distinguish environmental sounds. Patients report that they can identify many different types of sounds, such as footsteps, doors slamming, engines idling, telephones ringing, dogs barking, leaves rustling, birds chirping, and many other sounds.
  • Understand speech without lip-reading. Even if this level of hearing isn’t possible, the implant usually makes lip-reading easier.
  • Enjoy music. Some people enjoy the sound of certain instruments (piano or guitar, for example) and certain familiar songs. Other people who receive cochlear implants may not be able to enjoy music.

A few individuals with cochlear implants are even able to:

  • Use the telephone and understand familiar voices over the phone.

Criteria for Getting Cochlear Implants

Cochlear implants are FDA approved for use in adults and children as young as 12 months of age. The procedure has been performed in thousands of people, most with a good degree of success. Keep in mind, however, that you have to meet certain criteria in order to qualify for the procedure.

Health professionals weigh a number of different factors when determining whether or not cochlear implants are right for a particular patient. An evaluation to determine your eligibility may include:

  • Medical Evaluation—A physical exam of the ear to check for infection or any abnormality that would prevent surgery
  • Hearing Test—Determines your ability to hear with and without a hearing aid or aids
  • CT Scan—Examines the anatomy of the inner ear
  • Psychological Tests—Done to evaluate the motivation and expectations for the cochlear implant

Specific Criteria for Adults

The procedure is generally recommended for adults who:

  • Have severe or profound bilateral hearing loss
  • Receive limited or no benefit from hearing aids
  • Have sufficient motivation to re-learn how to hear
  • Have realistic expectations
  • Are healthy enough to undergo surgery

Specific Criteria for Children

The procedure is generally recommended for children who:

  • Have severe to profound bilateral hearing loss
  • Receive limited or no benefit from hearing aids
  • Have a family that is committed to helping the child learn how to hear
  • Have realistic expectations
  • Are healthy enough to have surgery

How The Procedure Is Done

Cochlear implant surgery is performed while the patient is under general anesthesia and takes approximately 3 to 4 hours. It involves:

  • Making an incision behind the ear
  • Forming a slight depression in the mastoid bone, where the internal part of the device is placed
  • Creating a small hole in the cochlea
  • Threading the electrodes from the internal device through the hole
  • Closing the incision, leaving the internal device beneath the skin

Follow-Up After Surgery

About a month after surgery, the patient has a follow-up appointment with the audiologist and receives the external speech processor and microphone. These external components are connected to the surgically implanted electrodes via a magnet. Then, the audiologist fine-tunes (tunes-up) the implant, making sound audible.

Resources

For more information about cochlear implants, visit the following Web sites: