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What is a Cochlear Implant? (Definition, Reasons, and Indication)

August 25th, 2017 | 4 min. read

By Chuck Leider

cochlear implants.jpg

You may have heard of the term ‘cochlear implant’ but are unsure exactly what it means. If you have lost your hearing or are extremely hard of hearing, a cochlear implant may help you to hear again. Below, we look at the cochlear implant definition, reasons for getting one, and candidacy indications that you may benefit from one of these devices.


What is a Cochlear Implant?


In essence, a Cochlear implant does the job that the damaged part of the inner ear can’t. But contrary to what you might think, a cochlear implant isn’t a hearing aid. A hearing aid amplifies sounds.

A cochlear implant, on the other hand, sends impulses to your auditory nerve that carries sound signals to your brain. It bypasses the damaged hair cells entirely. Although the implant won't make you hear normally again, you will be able to pick up on sounds.

Incoming sounds convert to electrical currents and transmit to various contacts on the internal wire. The process creates an electrical field that directly stimulates your auditory nerve. The implant is today widely recognized as a useful treatment for profound hearing loss.

The first commercial Cochear implant devices were approved in the mid ‘80s by the FDA. Around 58,000 devices had been implanted in U.S. adults and 38,000 in U.S. children, according to the National Institute on Deafness and Other Communication Disorders (NIDCD) figures from December 201.

Most people with a large degree of hearing loss will be able to understand speech either in person or over the phone better with a Cochlear implant than they could with a hearing aid. It can help you recognize sounds around you, like alarms, telephones, and doorbells. You may also find that you can pick up better on what people are saying in noisy places than you would with hearing aids. You could even begin to enjoy music again.

The Cochlear implant device consists of two parts. You need surgery to place the receiver-stimulator under your skin. You wear the other part, the speech processor, behind your ear just like a regular hearing aid. The external part is a little bigger than a normal hearing aid. It’s connected to the internal part through your skin using an external magnetic disk.


Reasons for a Cochlear Implant

There are various reasons that you could be a good candidate for a cochlear implant. It might be suitable for you if any of the following apply:

  • You have moderate to profound hearing loss in each ear.

  • You have residual low-frequency hearing.

  • You have normal hearing in one ear but have profound hearing loss in the other.

  • You have no other medical issues that could make surgery risky.

  • You’ve lost your hearing after you’ve developed language and speech.

  • You have a strong desire to communicate through speech reading, listening and speaking.

  • You find you receive little or no benefit from hearing aids

  • You score 65 percent or under on sentence recognition test in the affected ear.


Many individuals have bilateral cochlear implants (in both their ears). Bilateral implants are useful for identifying the directions of sounds and separating the sounds you wish to hear from ones you don’t.


The benefits of a cochlear implant include that you can:

  • Hear missed sounds. When your hearing loss is profound, you miss out on a lot of sounds, conversations and so on that others take for granted.

  • Have improved hearing with an implant than with a hearing aid. A 1999 study showed that that individuals with the implant could understand around 80 percent of sentences compared with only 10 percent of understanding for those with hearing aids.

  • Enjoy music. Music is a big part of many people’s lives. Being able to hear it again can bring great happiness.

  • Focus better in noisy environments. You’ll be able to hear better in restaurants, at meetings, in public places and so on.

  • Hear and talk on the phone. Communication is crucial to everyone. It’s particularly important when you have hearing loss.

  • Feel safer. You will feel safer when you can hear the everyday sounds people tend to take for granted, like alarms, people calling out and vehicles approaching.


Indication for a Cochlear Implant


Many aspects determine whether your implantation is to be a success. Generally speaking, you may be a good candidate for cochlear implant depending on the following:

  • How old you were when you became deaf.

  • How long you’ve been deaf.

  • How rapidly you learn.

  • How dedicated and good your learning support structure is.

  • How communicative you are.

  • The general health and structure of your cochlea.

A cochlear implant is a hearing solution if you have severe-to-profound sensorineural hearing loss or have single-sided deafness.


Severe-to-Profound Sensorineural Hearing Loss

Cochlear implants are suitable for adults and children with sensorineural hearing loss. This condition usually involves damage to tiny hair cells within an area of your inner ear known as the cochlea. These minute cells pick up sound vibrations and pass these via your auditory nerve to your brain. Sounds can’t reach the nerve if there is damage.

The eligibility criteria for cochlear implants for severe-to-profound sensorineural hearing loss include:

  • Previous use of an optimally fitted hearing aid, if appropriate

  • Functioning auditory nerve

  • Severe-to-profound hearing loss

  • Adequate expectations and motivation

  • Little or no benefit from acoustic amplification


Single-Sided Deafness

Single-sided deafness (SSD) or unilateral hearing loss is most often caused by surgical intervention to remove brain tumors, viral infections, ear or head injuries or Meniere’s disease. The symptoms of the condition vary.

You may find that in addition to your hearing impairment on one side, you can't tell what direction sounds are coming from. There's then a danger for you every time you cross a street or try to navigate traffic. Alternatively, you may be unable to hear sounds coming from a specific direction. A common problem is to be unable to separate background sounds from those you’re trying to hear.

SSD may not sound difficult to deal with. However, you face handicaps and need to change your lifestyle to fit in around your condition. You may find it hard to cope with everyday environments like family gatherings and business meetings You may feel yourself shrinking back from the world.

The eligibility criteria for cochlear implants for SSD includes:

  • Indication of mild-to-moderate hearing loss or normal hearing in the contralateral ear within a certain threshold.

  • Indication of severe-to-profound sensorineural hearing loss in an affected ear within a certain threshold.

  • Adequate expectations and motivation.

  • Functioning auditory nerve.

  • Little or no benefit from acoustic amplification.

  • Prior use, if appropriate of an optimally fitted hearing aid.


Children And Cochlear Implants

Cochlear implants are suitable for use in children from the age of one year upwards. The following indications must be present to show that a youngster is a good candidate:


Children From 12 To 24 Months

  • Limited benefit from binaural amplification

  • Profound sensorineural hearing loss


Children From Two to 17 Years

  • Limited benefit from binaural amplification

  • Severe to profound sensorineural hearing loss

  • Lexical Neighborhood Test (LNT) or Multisyllabic Lexical Neighborhood Test (MLNT) scores of less than 30 percent

Whether you’re a parent of a child who needs implants or you’re having one yourself, extensive rehab services help you learn how to handle communications, use speechreading, learn to listen and improve speech. You’re taught how exactly to use the implant and how to respond to these new sounds you’re receiving. Although these sounds could at first seem unnatural to you if you’ve heard before, you can get used to them.

Today, with advancements in technology and medicine, a Cochlear implant can even be placed in individuals with a malformed cochlea or a missing auditory nerve.

If you feel you may be a good candidate for a cochlear implant, the first step to take is to get in touch with us at Houston ENT & Allergy Services.



Request An Appointment with Houston ENT & Allergy Today!