TWO EARS ARE BETTER THAN ONE! EXCEPT WHEN ONE IS REALLY BAD......

According to Sergei Kochkin, Ph.D. of the Better Hearing Institute, there is an advantage to wearing two hearing aids. If you have hearing loss in both ears, then you are most likely a candidate for two hearing aids. While a hearing healthcare professional can best determine if you are a candidate for two hearing aids (a binaural fitting), the ultimate decision-maker concerning binaural instruments is the person who will wear them.

But what do you do if there is a significant difference between your ears. A good ear and a bad ear; a good ear and a "dead" ear; a "not perfect ear" and a bad ear. There is a solution for these situations. Instead of putting a hearing aid in that "bad" ear, wear a CROS system. A CROS system is a combination of a regular hearing aid for the better ear and a "transmitter" on the bad ear. The transmitter looks just like a regular hearing aid, but its job is to send the sound waves that it receives on the bad ear, around the head and into the hearing aid on the better ear. Typically the devices look the same on each ear, but they can be different if need be.



The benefit of the CROS system, is that your bad ear will "hear" as well as your better ear. For example, a person sitting on your "bad side" will sound just as good as the person sitting on your "good side". We are not really using the bad ear to process the sound, we are using it to gather sound from that side and send it to the other ear.

Now if you've tried CROS aids in the past, and had a negative experience, you should try them again. Talk about "new and improved!" In the past, they were huge behind-the-ear devices and originally were connected with a wire. But today's CROS systems are much smaller and communicate wirelessly.

Another good use for a CROS system is if you have one ear that is "clear" sounding, and the other ear is extremely "unclear", a CROS system can also help. Sometimes patients who have hearing loss due to Meniere's Disease will find themselves in this situation. It's not so much that there's a big difference in hearing, but there is a huge difference in the "clarity" of the ears. Louder, does not make the bad ear "clearer".

Another benefit of CROS systems is that they don't cost as much as two hearing devices because the transmitter is not an actual hearing aid. That makes the "CROS" device significantly less expensive. The hearing aid for the better ear can be any technology level; whatever that ear needs. So is there a disadvantage to CROS systems? There are a couple. CROS systems, because they are now wireless, tend to run the battery down faster. You can expect almost half the life that you would get with a regular hearing device. And the smaller the device, the smaller the battery.......the smaller the battery, the shorter the battery life. I prefer to only fit CROS devices with a size 13 battery, but if the patient wants discretion, there are CROS systems out there using the smaller 312 battery.

The other disadvantage of CROS systems is that by using a CROS device in the bad ear, you do not stimulate the hearing hair cells, as you were doing by wearing a regular hearing aid before. Sometimes, this needs to be considered, especially if the hearing loss has progressed quickly, and a cochlear implant may be in a patient's future. However, if the ear has been "unaided" for quite a while, or is a "dead" ear, then stimulating those hearing hair cells is no longer an issue, and the CROS system could make a difference.

COCHLEAR IMPLANTS: WILL I HEAR BETTER THAN WITH MY HEARING AIDS?

 

Patients often ask me if they will ever end up in a cochlear implant.  Generally, most people with hearing loss do not reach that point.  Your hearing has to reach the bottom of the audiogram (hearing test graph) before a cochlear implant will help you hear better than with your hearing aids.  Sometimes a patient may qualify for an implant even though their "graph" portion of the audiogram is not in the profound range.  That may occur if your ability to "understand" speech becomes very poor, even when wearing your hearing aids.  The portion of the cochlear implant that is visible to others is the "speech processor", which looks like a large behind-the-ear hearing aid.  The speech processor has a wire coming out of the bottom of it which leads to a round disk which attaches magnetically to the patient's skin, above their ear.  The rest of the device is the "implanted" part and is not visible to others.  Speech processors have all decreased in size, and have greatly improved over the years.  A more in-depth discussion of cochlear implants follows:

 

What is a Cochlear Implant?

 

A cochlear implant (CI) is a surgically implanted electronic device that can help provide a sense of sound to a severely hard of hearing or deaf person.  Cochlear implants may help provide hearing in patients who are deaf due to damage to the sensory hair cells in the cochlea.  An implant does not restore normal hearing. Instead, it can give a deaf person a useful representation of environmental sounds and assist them in understanding speech.  The surgery is performed by a Neurotologist (ear specialist), and the pre-operative testing, and post-operative programming of the device are performed by an audiologist.  There is typically a four to six week delay between surgery and device hook-up to allow the surgical incision to heal.

A cochlear implant consists of two main parts:

• An external portion that sits behind the patient's ear and consists of:
• A microphone which picks up sounds from the environment.
• A speech processor which selects, filters, and arranges sounds from the environment to be sent to electrodes in the cochlea.
• A transmitter which transmits power and the processed signal across the skin to the internal portion of the device.

• An internal portion that is surgically implanted under the skin and in the cochlea:
• A receiver/stimulator which receives the signal from the transmitter and converts it into electrical impulses.
• An electrode array which collects the electrical impulses and sends them to different regions of the auditory nerve. 

 

How does a Cochlear Implant work?

 

Cochlear implants are very different from hearing aids.  Hearing aids amplify sound and sends the signal from the outer ear through the middle ear into the cochlea.  The cochlea contains hair cells which have frequency (or "pitch") representation from high pitch to low pitch (think about a piano keyboard).  A cochlear implant bypasses the damaged hearing hair cells and directly simulates the auditory nerve in a frequency appropriate manner.  These electrical impulses on the auditory nerve are then sent directly to the brain for processing.  It takes time for patients to learn or re-learn how to process sound.  Some individuals may only learn to use the sounds for environmental awareness and safety, while others are able to use these sounds to have full conversations in person or on the phone.

What is the candidacy criteria for a Cochlear Implant?

The candidacy criteria for children and adults differ:  Current cochlear implant candidacy criteria for adults:  (Boys Town Research Hospital Website)

• Bilateral (both ears) moderate to profound sensorineural hearing loss (thresholds of 40 dB HL or greater)
• Limited benefit with appropriately fit hearing aids, defined as pre-operative test scores of:  ≤50% understanding of sentences in the ear that is to be implanted or ≤60% understanding of sentences when tested bilaterally (best aided condition)
• No physical contraindications for placement of the implant (i.e., CT scan results)
• Medically cleared to undergo surgery
• Realistic expectations
• Commitment to follow-up appointments

What are some Contraindications to receiving a Cochlear Implant?

• Deafness due to lesions of the acoustic nerve or central auditory pathway
• Active middle ear infection
• Absence of cochlear development
• Tympanic membrane (ear drum) perforations in the presence of active middle ear disease
• Medically unstable to undergo surgery
• Unrealistic expectations
• Not committed to follow-up appointments

Information from the NIH: National Institute of Deafness and Other Communication Disorders (NIDCD)