All about cochlear implants

June 29, 2016
Cochlear implants may be the next step when hearing aids no longer help a person understand speech well. They also can be the first step for infants born with little or no hearing. But these implants are much different than hearing aids, and so is the process of determining whether someone is a good candidate for a cochlear implant.

When patients come in for a consultation, they usually don’t know what to expect and they have many questions. In this blog post, I’m going to answer some of the most common questions and provide important information for people who might be considering a cochlear implant.

How do hearing aids and cochlear implants differ?

Hearing aids are external devices that are worn in or behind the ear. They amplify sound, which is processed by a person’s remaining hearing.  A cochlear implant doesn’t amplify sound. Instead, it bypasses the outer ear, middle ear and most of the inner ear. It changes speech and other sounds into electrical energy that is used to stimulate surviving hearing nerve fibers in the inner ear, or cochlea.  

Cochlear implants have an internal device and an external speech processor. Placement of the internal device requires surgery.

Hearing aids are useful when a person’s hearing loss falls in these ranges:

• Mild
• Moderate
• Moderately severe
• Possibly severe

Patients are only candidates for a cochlear implant when their hearing loss is:

• Within the severe to profound range
• They struggle with communication even with hearing aids 

It’s important to remember that providers also weigh other potential medical issues and psychological considerations when they evaluate a person for a cochlear implant.

What is a cochlear implant?

As we’ve learned, a cochlear implant has internal and external parts. The internal part is implanted in the temporal bone behind the ear, and an electrode array is placed in the cochlea of the inner ear. The device’s speech and sound processor is worn behind the ear. The processor converts speech and sounds into electrical energy that’s used by the implant to directly stimulate the hearing nerve.

Infants from 8 months to people over 90 have received cochlear implants. What they all have in common is sensorineural hearing loss, which occurs when there’s damage to the cochlea or auditory nerve. 

In general, cochlear implants are appropriate for:

• Adults with moderate to profound sensorineural hearing loss in both ears
• Children ages 2 to 18 years with severe to profound sensorineural hearing loss in both ears
• Children younger than 2 with profound sensorineural hearing loss in both ears

There is growing evidence, however, that some patients who are deaf in one ear or have significant tinnitus can benefit from a cochlear implant, so non-traditional candidates also are being considered.

How do I know if I am a candidate?

Whether a person is a candidate for a cochlear implant is determined over a series of audiology and medical appointments. Any or all of these steps may be required:

Complete hearing evaluation – For children, several appointments may be necessary for accurate results. 
Hearing aid evaluation – Your hearing aids will be checked to see how well they work and how well you function with them. This evaluation includes tests to determine how well the hearing aids help you with speech perception.
Counseling sessions – Your audiologist and a surgeon will meet with you and your family to discuss the benefits, limitations and expectations of a cochlear implant. They also will go over the three cochlear devices available to help you decide what would be best for you or your child.
Medical assessment – This typically includes a CT scan and/or MRI, and an exam by an otologist, a doctor who specializes in hearing loss. Children with cochlear implants are at greater risk for bacterial meningitis, so they also will receive recommendations for a pneumococcal vaccine. Last, some candidates also may need balance testing and/or a psychological evaluation.  

What are the outcomes and benefits of cochlear implantation?

It’s important to realize that cochlear implants do not restore normal hearing. And how well they work is based on many factors, including:

• How long a person has had hearing loss
• How old a person was when hearing loss began 
• Whether the person has used hearing aids
• The degree of hearing the person had during the critical language-learning years, typically before age 5
• How old the person is at the time of implantation 
• The condition of the inner ear and hearing nerve
• Whether a person has had meningitis
• Related medical conditions 

What can I expect to hear with an implant?

We can’t predict how well a cochlear implant will help someone hear, but there are a range of possibilities. Here are some of them:

• Detection of everyday sounds, such as a door bell, birds singing and voices
• Environmental awareness and a better connection to the sounds around you
• Improvements in communication through hearing and speech reading
• Limited speech understanding without speech reading in quiet listening situations
• Speech understanding in quiet listening situations 
• Limited speech understanding in listening situations with mild background noise
• The ability to hear on the telephone
• The ability to listen to and appreciate music

How can you best prepare yourself for a cochlear implant evaluation? 

• Bring prior hearing tests so your cochlear implant audiologist can understand your type of hearing loss and its progression.  
• If you are currently using hearing aids, have your hearing aid audiologist ensure that they are functioning properly and programed to your most recent hearing test.   
• Bring questions!  Remember, you are an active participant in this process and we want you to be able to make the best decision for you! 

Now that you know what to expect during the cochlear implant evaluation process, I will explain what to expect after you or your child receives an implant. Stay tuned!

Learn more about hearing services at Swedish here, or call 1-800-793-3474 for an appointment.


Topics: Audiology