Hearing with Two Ears: A Balancing Act

There are a lot of reasons, research, and rationale to support the need for bilateral amplification for people with hearing loss.  It’s pretty much a “given” at this point in our field, though, sadly, there are still some insurance companies and even hearing healthcare professionals who lag behind the curve.  What should you consider if you or your child have just one cochlear implant and are thinking about going bilateral?  How do you get a second ear “up to speed” if there’s a significant gap between implant dates?  Is it worthwhile to continue using a hearing aid in the other ear after you receive a CI?  How can users or bilateral hearing devices get the most out of their two ears?

 

Choosing to Go Bilateral

There are many, many reasons why bilateral hearing is preferable.  Humans are naturally born with two ears for a purpose!  Read HERE for a detailed explanation of the benefits of bilateral hearing and how to make the case for bilateral implants to your insurance.  If bilateral cochlear implantation is an option for you or your child, and both ears are CI candidates, it is highly advisable to go for simultaneous bilateral implants as soon as possible.

If you/your child currently have one cochlear implant and are thinking taking the leap for that second ear, here are some things to consider:

  • There are many benefits to having two ears.  Bilateral implantation provides improved localization (ability to detect the source of sound), better hearing in noise, and makes soft sounds more audible (the summation effect = two ears make sounds seem louder than each ear hearing it separately).

  • Another benefit that I feel is deserving of special note is the fact that bilateral amplification has been shown to reduce listening fatigue.  Think about it: what would it be like to run a marathon with one leg or paddle a rowboat with one arm all day, every day?  That’s essentially what you’re doing when trying to listen at school, home, or work with just one ear.  For a comparison, we can look at the statistics on children with unilateral hearing loss: one ear functioning within normal limits and the other with some degree of hearing loss.  Those children are up to ten times more likely to fail a grade, and about 20% are reported for behavior or social problems.  It’s a big deal!  (And we should consider that one ear hearing WNL without amplification is an even better scenario than a unilateral implant user, who is still hearing through a CI, which, however great, is not a perfect replica of natural hearing.)  Whether you’re a baby trying to learn language, a child trying to keep up in school, or an adult trying to be successful on the job, listening fatigue is a real reason to consider going bilateral.

  • Compared to the benefits of bilateral CI hearing, what are you truly gaining from your other ear as it is?  If the other ear’s hearing, even with a hearing aid, is only enough to appreciate environmental sounds and not enough for understanding speech and language, is it worth it?  For children, my answer is almost always no.  If we know it’s possible, then I want two ears that are mapped to the gold standard and nothing less.  Developing speech, language, listening, and cognitive skills during this critical period is far more important than keeping that hearing aid ear around on the off chance that it might be able to hear a dog barking or some other environmental sound.  Adults may make a different choice, though I still think having two ears to help you hear in conversation (see the discussion about benefits and fatigue above) is well worth going bilateral, but for children, we do not have the luxury of waiting or keeping around an ear that is not pulling its weight.

  • Do not wait!  Waiting for new hearing technology is not a good reason to put off a second implant.  The research on cochlear implants, residual hearing, and hybrid CIs shows us that thinking you are “saving an ear” for future breakthroughs is a false assumption.  The smaller the gap between ears, the better your brain is able to adapt.

  • If you’re having trouble getting your insurance to cover a bilateral operation, see THIS list of suggestions for how to make your case.

 

Gaps Between Ears

In general, the smaller the amount of time that has elapsed between getting each ear “on the air,” the better.  Our goal is for synchronous brain development, so we want both ears to have the auditory signal at the same time, or with as little delay as possible.  That’s not to say, however, that people have not been successful with bilateral cochlear implants even if ear #1 and ear #2 were implanted years apart.  Contributing factors include whether or not the contralateral (opposite side) ear was amplified (e.g. was the person a good, consistent hearing aid user in the other ear, keeping that auditory nerve stimulated?), the person’s overall communication (people who rely on listening and spoken language have brains more ready for sound than those who are manual communicators), the state of the cochlea and auditory nerve (was their ossification/bony growth in the cochlea over time?  has the auditory nerve atrophied?), and the therapy that person receives (more on that later).

A common question I hear is, “It’s been X years since my first ear was implanted.  Is it worth it to go for the second or am I too late?”  My answer is this: it’s been X years now, and tomorrow it’ll be X years + 1 day.  You’re never as close again as you will be right now.  There are many benefits awaiting you if you act, and they’re only diminishing every day you wait.  Act now!”

 

Contralateral Amplification (Aiding the Un-Implanted Ear)

If you or your child have a cochlear implant in one ear, is it worthwhile to continue to wear a hearing aid in the other (contralateral ear)?  In almost all cases, the answer is YES!  Stimulating that other ear is important, too.  It keeps the auditory nerve and pathways to the brain working, exercised, and strong (as long as you are using an approach that encourages listening and spoken language), provides help for localization and hearing in noise, and, with the HA + CI combination, may contribute to better hearing of base tones and contours of sound (some have noted that this is especially true for music appreciation).    If the contralateral ear is a CI candidate (see more information above, as well as considerations for borderline candidates HERE), it’s important to try to get that second implant ASAP (see above), but in the meantime, it is very valuable to keep that ear stimulated.

 

When is contralateral amplification not recommended?

  • The other ear has no cochlea or hearing nerve.  Obviously, if there’s some anatomical anomaly and there’s nothing there to stimulate, it’s not worth putting a “three thousand dollar earring” on that ear.

  • Some people with Auditory Neuropathy Spectrum Disorder report that, while the cochlear implant provides clarity (as it takes the place of the faulty auditory system), the hearing aid, which simply amplifies sounds, provides a poor, confusing, or garbled signal to the other ear.  If wearing a hearing aid in the other ear is confusing or frustrating a person with ANSD who is successful with the CI on its own, then it may be time to discontinue the use of the hearing aid.  In fact, some people with ANSD will actually wear an earplug in that contralateral ear to make sure that they’re only hearing from the CI, as it provides a clear and more synchronous sound than their ears to on their own or with a hearing aid.  ANSD is tricky, and these decisions about implantation and the use or disuse of a hearing aid should be made in consultation with a Listening and Spoken Language Specialist, audiologist, and surgeon who have experience with these cases.

 

Getting a New Ear Up to Speed

Rehabilitation is crucial to success for any hearing device user, whether you receive both devices at once (simultaneously) or one after the other (sequentially).  Even if a child or adult has a fully established language system and “graduated” from therapy years ago, introducing a second ear (or moving from HA to CI in that second ear) is worth a trip back for a short run of rehabilitation to make sure both ears are working together and that the second ear is working up to speed.  It’s important to spend time focusing specifically on the new ear alone until it is working on par with the first ear.  Without rehabilitation, many of the benefits of binaural hearing can be lost.  A Listening and Spoken Language Specialist has specialized training in auditory verbal therapy and auditory brain development and can help you get the most out of your technology.  Remember that success is 10% hardware (the device) and 90% software (the rehabilitation).  Don’t cheat yourself out of the full potential of hearing with both ears.

If you need help getting that second ear up to speed, contact me!  I can help.

 

Finding Balance and Getting the Most out of Your Two Hearing Devices

It’s important to remember that your two ears don’t work in separate vacuums.  They are constantly working together to help you hear your best.  As such, we have to keep this in mind when programming devices, whether it’s two CIs or a CI and a hearing aid.  Each device’s setting should be programmed separately, but then it’s essential that your audiologist tests you in the booth with both devices together before sending you off on your way.  Sometimes each ear can sound great on its own, but the combination of the two together makes sounds too loud, distorted, or uncomfortable.  It’s usually a simple fix, but this is something you want to find out during your appointment, not on the walk through the parking lot back to your car.

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One thought on “Hearing with Two Ears: A Balancing Act

  1. Hi Elizabeth

    Great article.

    I’m really glad you put in that bit about ANSD and bi-modal. In NZ we are seeing really good results for ANSD kids where they block the ears so only the CI input gets through. Adding a HA to the other side on a unilaterally implanted kid seems to undo the good work of the CI.

    I was wondering about the section on habilitation for a sequentially implanted ear. This seems to be an area where no one has landed on an optimal way of doing this. Currently in NZ they are saying you should do a bit of time each day with the newer ear only. But what seems to be missing is work on developing directionality and discernment in noise. These are two things I worked on a lot with my daughter (simultaneously implanted) and she is very strong in both those areas.

    Anyway… it would be really cool if you would consider writing an article on that habilitation of the second ear issue.

    Kind regards

    Sym

    >

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