Cochlear Implants

1 What are Cochlear Implants?

A cochlear implant is an electronic device that is implanted to partially restore hearing in people who have severe hearing complications due to damage to the inner ear and who receive limited benefits from hearing aids.

The system is made up of two central pieces: a processor that fits behind the ear and an internal piece implanted under the skin.

The processor captures and processes signals, which are transmitted to the receiver implanted behind the ear. The receiver sends the signals to electrodes sitting in the snail-shaped inner ear (cochlea).

These signals are then received by the auditory nerve and directed to the nerve. The brain interprets those signals as sounds, though these sounds will not be just like normal hearing.

It takes time and training to learn how to interpret the signals received from a cochlear implant, though most patients make considerable gains in speech understanding after a year of use.

2 Reasons for Procedure

Here are the most common reasons to receive cochlear implants.

A cochlear implant is an option for individuals who are after improved hearing after having their hearing ability significantly impaired due to damage to their ear.

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3 Potential Risks

A cochlear implant may have the following risks:

  • Injury to the facial nerve: This nerve goes through the middle ear to give movement of the facial muscles. It lies close to the position where the surgeon has to place the implant, and thus harm can be caused to it during surgery. A potential injury to this nerve can cause a temporary or permanent weakening or full paralysis on the same side of the face as the implant.
  • Meningitis: This is an infection of the lining of the face of the brain. Individuals who have abnormally formed inner ear structures appear to be at a greater risk of this rare but very serious complication.
  • Infection of the skin wound
  • Attack of dizziness or vertigo
  • Perilymph fluid leakage: The inner ear or cochlea contains fluid. This fluid can leak through the hole that was created for making the implant.
  • Cerebrospinal fluid leakage: The brain is surrounded by fluid that may leak from a hole that is created in the inner ear or elsewhere from a hole in the covering of the brain caused by the surgical procedure.
  • Tinnitus: This is a ringing or buzzing sound in the ear.
  • Taste disruptions: The nerve that innervates the tongue also goes through the middle ear. It might be injured during the procedure.
  • Numbness around the ear
  • Reparative granuloma: This is as a result of localized inflammation that can occur if the body rejects the implant.

4 What to Expect

Read on to learn more about what to expect before, during, and after your cochlear implants.

Before surgery

Your primary care doctor will refer you to a nose and throat doctors (ENT doctors or otolaryngologists) to test you in order to see you are a candidate for a cochlear implant.

The following tests are usually done:

  • An examination of the external, middle and inner ear for any signs of abnormality or infection.
  • Various tests of hearing, such as an audiogram.
  • A trial of hearing aid used to assess its potential benefit.

Exams to make an evaluation of the middle and inner ear structures:

  • CT (computerized tomography) Scan: This type of X-ray will help your doctor see if the cochlea has a normal shape. This scan is especially important if you have a history of meningitis because it helps see if there is new bone outgrowth in the cochlea that could be an impediment to the insertion of the implant. This scan may also indicate which ear should be implanted.
  • Psychological examination to see if the patient has the capability of coping with the implant.
  • A physical exam to prepare for general anesthesia.

During surgery

Your health care team may do the following

  • Insert some intravenous (IV) lines.
  • Shave or clean the scalp around the area of the implant.
  • Attach cables, monitors, and patches on your face to provide oxygen and anesthetic mask.
  • Administer drugs through the IV and the face mask to cause sleep and general anesthesia.
  • Wake you up in the operating room and take you to a recovery room until all the anesthesia wears off.

After the surgery

Immediately after waking up, you might feel the following:

  • Pressure or discomfort over youR implanted ear
  • Dizziness
  • Nausea
  • A sore throat for a while from the breathing tube used during general anesthesia.

You will be expected to do the following:

  • Keep the bandages on for a while even if the bandages are stained with some blood or fluid.
  • Stay in the hospital for a day before going home.
  • Having your stitches for a while. Get the instructions about caring for the stitches, washing the head, showering, general care, and diet.
  • Have an appointment in about a week to have the stitches removed and have the implant site examined.
  • Has the implant turned on (activated) about 3 to 6 weeks later?

5 Procedure Results

Cochlear implant results may vary from one individual to the next.

Most individuals find that cochlear implants help them communicate better and improve their overall quality of life. They report improved:

  • Ability to hear speech without the help of visual cues
  • Recognition of normal, everyday environmental sounds
  • Speech reading
  • Ability to hear soft sounds
  • Ability to determine where sounds are coming from
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