Cochlear Implants | How Do They Work? | MedStar Health
Dr. Selena Briggs poses for a photo while holding a cochlear implant device in her office at MedStar Health.

Cochlear implants are small, implantable devices that restore hearing perception to those who do not benefit from wearing conventional hearing aids. While conventional hearing aids amplify sounds, the cochlear implant bypasses impaired inner ear structures and stimulates the hearing/auditory nerve. As of December 2019, approximately 736,900 people worldwide have received cochlear implants. MedStar Health offers some of the most advanced options in auditory rehabilitation including bilateral cochlear implants, hybrid, and other hearing preservation devices and approaches.

Cochlear Implants

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A device called a cochlear implant can restore hearing by replacing damaged structures in the inner ear with a wire that is implanted in the cochlea.

How natural hearing works

Understanding how natural hearing works is important before explaining how a cochlear implant works.

Medical illstration of how the ear receives sound waves.
  1. Sound waves enter the ear canal and contact the eardrum (tympanic membrane).
  2. After the eardrum picks up the sound, it transmits sound through the three ear bones, known as the hammer (malleus), anvil (incus), and stirrup (stapes). The stirrup passes the vibrations to the inner ear fluids within the cochlea.
  3. Fluid waves travel through two and a half (2 ½) turns of the cochlea and stimulate the cochlear sensory organ, hair cells.
  4. The hair cells are tuned to respond to the wide range of frequencies or pitches of the original sound waves, initiating signals within their corresponding hearing/auditory nerve endings prior to sending them to the brain.

How cochlear implants work

The use of cochlear implants for the treatment of moderate to profound hearing loss is a revolutionary treatment and has been called one of the single most effective health interventions of our time. A cochlear implant is an electronic device that is partially implanted surgically into the cochlea, the hearing organ of the inner ear. It uses electrical current to bypass damaged or missing portions of the inner ear and stimulates remaining hearing nerve fibers. A microphone, processor, and transmitter are worn externally to control the implanted internal device.

Medical illustration and description of a cochlear implant and ear anatomy

Implants vs. hearing aids

A young woman puts in her cochlear implant device while standing outdoors.

Hearing is a complex process that originates in the cochlea: the organ of hearing that is located inside the temporal bone of the skull. The cochlea contains thousands of microscopic sensory cells that work much like the keys on a piano. Each sensory cell, called a hair cell, is organized and tuned to match a specific pitch. In a normal hearing person, these sensory cells respond to acoustic/sound information in the environment and translate it into a neurological code that is transmitted through the hearing nerve to the brain where understanding of the sound happens. If any of these sensory cells do not work properly, the information that arrives in the brain will be distorted and incomplete. The listener may have difficulty understanding what is said.

In the presence of hearing loss, when the sensory hair cells are permanently damaged and/or missing, incomplete, and distorted sound arrives at the brain. Hearing aids only make sounds louder and can compensate for partially damaged hair cells, but they cannot overcome significant and permanent hair cell damage.

A cochlear implant is not a hearing aid. Instead, it is a neural prosthesis that helps to provide hearing to people with moderate to profound hearing loss by bypassing the damaged sensory cells of the cochlea for individuals that obtain little or no benefit form sound amplification by hearing aids. The patient’s traditional means of hearing “acoustic hearing” is then replaced with “electric hearing” through the cochlear implant.

Criteria (who is a candidate)

With technical advances in cochlear implant technology, the minimal criteria have been evolving, with a broader patient population meeting criteria for candidacy for children and adults.

What are the risks?

Risks specific to cochlear implant surgery

  • Loss of natural (or residual) hearing in implanted ear
  • Greater chance for infection around the brain and spinal cord (known as meningitis)
  • Facial nerve stimulation resulting in involuntary facial twitching
  • Swelling (inflammation) / Pushing or thrusting out (extrusion) of device
  • Soreness, redness, breakdown of skin in area around device
  • Failure of implanted device, sometimes requiring reimplantation

Risks with any ear surgery

  • Numbness / tenderness around the ear
  • Injury to the facial nerve / facial paralysis (facial drooping)
  • Taste change (dry mouth or metallic taste in mouth)
  • Leak of inner ear fluid (perilymph) or fluid that surrounds the brain (cerebrospinal fluid)
  • Dizziness or vertigo
  • Ringing in the ears (tinnitus)
  • Local complications such as blood/fluid collection or infection at or near surgery site
  • Rashes (skin reactions)

General risks

  • Post-surgery pain, scarring, bleeding, and infection
  • Risks associated with being put to sleep or general anesthesia (problems with the heart, lungs, kidneys, liver, and brain due to general anesthesia)

Implant costs

Cochlear implantation and its benefit to individuals with moderate to profound hearing loss is a well-documented medical procedure. Medicare or Medicaid along with most major, private insurance companies recognize its significant benefit and medical necessity and typically offer 80-100% coverage of the costs of the surgery and the implant system.

Once candidacy for the process has been determined and a surgery date established, we will work with your insurance on your behalf to obtain an authorization for the cochlear implant surgery. Every patient's medical coverage is unique, which can affect the overall cost of the surgery. Your care team will work with you with regards to financing. We will discuss your individual insurance plan and your potential out-of-pocket expenses associated with the surgery.

Our locations

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MedStar Health: Otolaryngology at MedStar Georgetown University Hospital

3800 Reservoir Rd.
1st Fl. Gorman Building
Washington, D.C., 20007

MedStar Health: Otolaryngology at MedStar Washington Hospital Center

106 Irving St., NW
Physicians Office Building
Ste. 2700 North
Washington, DC 20010