Presentation by Dr. Niparko
HISTORY OF COCHLEAR IMPLANTS
The first cochlear was performed in 1956 in France on a patient with a severe ear infection. After the infection was taken out, a wire was placed on the hearing nerve, which was visible due to all the destruction from the infection. The patient reported over the next three days that he heard a variety of sounds when current from a battery pack was applied to the wire. Doctors were surprised because they expected the patient would feel a sensation or perhaps some pain in the ear, but they did not expect the patient to report he could actually hear something.
The wire was left in for only a few weeks because culturally Deaf people in Paris heard about the experiment and claimed that it was a completely unethical. Nothing more happened until 1962 when a group of doctors in Los Angeles tried the same thing. They had some success, but technology was not yet available for coating a wire so that it would keep functioning over time. These early experiments showed that even in a destroyed ear, the nerve could retain its sensitivity and respond to stimulation.
Ten years later, technology from the NASA exploration helped develop the electronics into a small package that was sealed to function over a long period of time.
WHO CAN BE IMPLANTED
In the U.S. there are 22 to 28 million people who cannot understand speech at 30 feet without amplification. That is 10% of the population. Not all of them are candidates for a cochlear implant.
Perhaps one of the most dynamic aspects of cochlear implants today is deciding who is a candidate for an implant, and to rephrase the question, when is an implant going to provide more speech understanding than hearing aids? Dr. Niparko said.
More people are now candidates for implants than two years ago because technology is so much more advanced. Most people with a cochlear implant have hearing down to about the 90 to 100 decibel area on their audiograms.
Some people with hearing aids actually understand most of the speech sounds even though their charts make them appear to be deaf. The theory is that they have some high frequency hearing that allows them to get the full range of speech sounds.
One way to see if you are a candidate for an implant is to look at whether you can hear 2,000 hertz tones at 45 decibels. If you can hear that with your hearing aids, you are probably not a candidate for an implant. Whats most important with candidacy is not so much your threshold, Dr. Niparko reports. It is how you understand speech.
The test being used by Johns Hopkins for deciding cochlear implant candidates has changed during the past year. It used to be a test to understand sentences, but many people were tested so often that they knew the sentences used already. Other people are so skilled at piecing things together that they may get only one or two words and figure out the entire sentence even when they have not really heard all the words. As a result, Johns Hopkins now tests with single words to see how many you understand.
More changes are in the works, according to Dr. Niparko. More recently its been discussed that what we really should do is test your hearing of single words in a noisy background. Thats an area for active research right now, because many people in a soundproof booth can do quite well with hearing aids in repeating words and sentences.
Normally there are all kinds of other noises such as fans running that make it more difficult to extract the information needed to understand speech. Dr. Niparko expects that within the next year or two this will be taken into account in testing for cochlear implant candidacy.
Candidates for implants also will need to get a CAT scan which will tell the condition of the inner ear and whether the array of contacts can be placed easily within it.
COCHLEAR IMPLANT SURGERY
Surgery today is much different from surgery in the past, and it continues to change rapidly.
Today we do 95 percent of this surgery on an outpatient basis, and that allows us, in many cases, or actually requires us, to do the surgery quickly and in a way where you wouldnt have as much pain as you would with surgery five years ago, Dr. Niparko said. To accomplish that we have gone to a smaller incision.
The surgery now takes about 1 1/2 hours and you wear a thick dressing for two or three days after the surgery. The typical patient is back to normal activity in three to four days, but its a very individual recovery.
ACTIVATING THE IMPLANT
The implant is activated in 3 to 4 weeks. There are many questions that come up at that time. Dr. Niparko recommends that people undergoing implants talk with other implant users to know what an implant sounds like and get support.
The newest devices use a pattern of stimulation that is much more natural than what we were using two years ago, Dr. Niparko said.
He used the example of playing a chord of three notes together on a piano. In the old days, the notes were played separately on the implant. Now the circuits in the implant allow for a faster transfer of information so that the chord can be played all together in your ear.
Speech sounds are much like a chord on the piano. They contain different pitches at the same time. The new, faster transmission thus makes for more natural speech sounds. Your brain takes this information to put together a gestalt to tell you exactly what information is coming to you from the outside world.
If you have recently lost your hearing, the chance that you can understand what you are hearing with an implant is much better because you are more familiar with the information you receive. That is why the amount of time since you lost your hearing is one of the most important ways to predict how well you will do with an implant.
If you had a good foundation of hearing through your early life and you developed good spoken English skills and are a good lipreader, chances are that you have the mental images in place to be able to put together the information that an implant can gather, Dr. Niparko said.
WHAT IS THE BENEFIT?
Dr. Niparko addressed the benefits of a cochlear implant:
What are we really accomplishing? If you look at everybody who has an implant, how many of them like it?
You know what? We dont know. Ill be honest with you. Of the 20,000 people in America who have received an implant, only about 25 percent of them have been followed in research protocols.
We do know, based on clinical estimates, that 95 percent of people with an implant are using them. That is one indicator of success. I believe that if you are willing to change the batteries every day, and youre willing to go ahead and place the hardware on your scalp, you must be getting something from it.
A number of smaller studies have been done. At Johns Hopkins, 240 implantees were studied. The average threshold is about 32 or 34 decibels across the speech frequencies. Some people are at 10 decibel hearing with their implants, very close to normal hearing. But Dr. Niparko cautions that doesnt mean they understand something. You can hear something in many cases that you cant quite understand.
The Hopkins study also found that people who had implants understood an average of 50% of words and 80% of sentences after one year. Some people are able to hear with implants immediately, even talk on the telephone the first day, but that is very rare.
What has to happen is that your brain has to make use of the information, interpret it, and thats why there can be a significant period of growth before you can understand speech using the implant.
Dr. Niparko believes that the most important measure of an implants success is how it affecting the quality of your life. Johns Hopkins and 11 other centers in the U.S. and Canada are participating in a study where 41 patients who received implants in a four-month period were studied to find out the quality of their lives six months and 12 months later. This was also compared to the responses from 14 people who could be implanted but were not because their insurance companies would not cover the cost. The results of the study showed that within a year the implanted group was reporting a 40% increase in quality of life. The study measured not just communication ability but also things like time spent outside the house, effectiveness of your work, and emotional health.
This figure is considered remarkable. Dr. Niparko commented, I think what this says to the nation and to our government and our insurance companies is that hearing is a very important faculty for keeping you connected to the world, and were learning more and more about how important that is, not just to everyday communication, but perhaps also to your physical and emotional health.
*Copyright 1997 by Northern Virginia Resource Center for Deaf and Hard of Hearing Persons, 10363 Democracy Lane, Fairfax, VA 22030. We strongly encourage you to share this information, but please be sure to credit NVRC.*
Q: At last years Miniconference, a lot of people mentioned having tinnitus after their implants. Is it that common a problem?
A: Tinnitus is thought to be the brains response to a loss of signals that normally come from the ear. It tends to occur more in patients who have had trauma to their ears, usually noise trauma. About half of people who have tinnitus before implant surgery say its better after the surgery. For people who have never had tinnitus before an implant, about 10 to 20 percent have it during the first year. It might mean that there was trauma to the ear in placing the implant, but it goes away or at least becomes less noticeable over time.
Q: What happens with the people whose tinnitus remains?
A: The best study done on implants in adults was by the Veterans Administration. It was published in the New England Journal of Medicine in 1993. The study followed 120 veterans over four years. It indicated that tinnitus occurred in something like five percent after one year. Patients whose tinnitus continued after the first year often say that the tinnitus happens whether or not their implant is turned on. But they find that when the implant is on, it helps to mask the tinnitus.
We know that in the United States, for example, ten or fifteen percent of our population experiences tinnitus, and yet the number of people who go to a doctor for treatment of tinnitus is only one percent.
The one percent who do see a doctor tend to be people who have a more severe hearing loss and also tend not to have strong coping mechanisms. The ability to deal with the problem is eroded, and a higher percentage of them will receive medication for depression. They report their tinnitus is not as loud when they take that medication, but its not clear if their coping mechanism is stronger or the medication reduces tinnitus, or both. Prozac has been found to be effective in treating tinnitus.
Q: I have an implant and Im going back for a third mapping. I want to socialize more. I just cant do very well. I know there is a new beam available. I have a directional microphone but its just not doing enough.
A: Most people rely on hearing in social gatherings that tend to be noisy places -- at work, running errands, out shopping, family holiday gatherings. Thats when you want your hearing to function best, but its the most difficult situation to hear in.
Normally our ears are pretty good at focusing on the speaker, at detecting the information, estimating the loudness and the pitches, putting all of this together, along with context...but when it comes to talking to someone that you dont know and youre not sure what theyre going to say, and there is a noisy background, it is very difficult to pull out that speech information, especially with a damaged ear.
Cochlear implants are good at detection. They also can outperform hearing aids. But detecting the right things without the background noise is a challenge. The I-beam technology uses two microphones and takes the information coming from the area in front of you to your processor, sound that is at a steady state, such as the hum of a ceiling fan, is eliminated. This will give you only the dynamic information coming from speech. Two patients now use this beam with their Nucleus implants with great satisfaction. It requires extra hardware. You have something that goes on top of your processor and two wires that go to your ears. Ear-level processing is expected in the next year or two which may give some real advances to get rid of background noise.
Q: With all the great advances in the past couple of years in implant technology, what is your advice for someone considering an implant but nervous that implants could become radically better soon after being implanted?
A: Professionals used to say that most of the upgrades were going to be to the external device, the processor, where computer technology has moved quickly, or software programs improved.
There were no indications that there would be a substantial upgrade to the implant itself. That has changed.
I honestly believe that an implant will be available in four or five years that will probably offer a greater level of hearing than anything we have even today. Moreover, that implant will probably not need an external processor at all. The entire implant will be internal.
But those who are thinking about the implant may think they should wait until 2002. However, when the first fully implantable cochlear implant comes out, the FDA will permit tests on 20 people. The FDA will then say there must be a wait of three years before any more can be implanted. Almost invariably, there will be a problem with the first new implants, so they will be redesigned. By 2005, the FDA will allow 20 more people to be implanted with the redesigned implant. Two years later, if all goes well, the implant will be available on the open market.
My advice to you is if you are struggling, there are very few good reasons to hold off on this technology. I know that a desk top computer will be much better five years ago that it is today, but the reality is that I need it today.
Q: I have an implant already. Should I upgrade?
A: Were not going to tell you to change unless we have exhausted every possibility with your processor for giving you the same level of benefit.
If there is no benefit and you want the surgery, it is much easier to do. At Johns Hopkins, it takes about 15 minutes. It could probably be done under local anesthesia. The work to expose the inner nerve has already been accomplished, so taking an old implant out and putting a new one in the same position is simpler.
There are so many people now who have received newer implants and have improved their performance that we are confident you can have an old device taken out and a new one put in without compromising the function of the second.
Q: How do you decide which ear to use? Are there ears so deaf that you cant get good results?
A: In choosing an ear, the one with poorer hearing is preferred. But it can only be used if tests show the ear is still sensitive to signals. A probe is placed in the inner ear and the patient is asked to tell if there is a sensation of sound. That is a good way to predict that the ear will respond to the implant.
Q: If you dont get that response, would you still implant the better ear?
A: It depends on how much hearing you have. If you can hear sounds but cant understand speech, that would probably be a good ear for implantation.
I can guarantee that any ear that is implanted will respond to sound. What we cant guarantee is that youll understand speech. That is more of an internal process that requires training, requires patience, and requires a lot of effort.
Word understanding in patients at Johns Hopkins is now approaching 50% for single words. No one would be considered for an implant in an ear that has close to 50% understanding.
Q: If a person is doing well with one kind of implant, could they get another in the future?
A: That depends on how the new implants stack up and whether we could expect any gain that would make it worthwhile.
I think for many individuals who are using older technology, your brain has sort of shaped the connection around that information. We have probably got very good at using it, and the chance that there would be a dramatic improvement with a newer device is probably small.
Q: Is there an age limit for implants?
A: I dont believe that there should be an age limit, and a lot of my thinking on that was shaped by an experience that I had early on where an 85-year-old gentleman in the VA trial insisted that he receive an implant. I said I didnt think it was worth all the time and effort and rehabilitation and all. His family, his insurance company, and his mayor -- the mayor of his city -- wrote me a letter telling me that I was wrong, that he deserved an implant.
I changed my mind and said okay. And when he told me that he had heard his grandson and granddaughter for the first time, and he had heard their children for the first time, I knew we had made the right decision.
Q: I became deaf at age three. I have an implant and was hooked up two months ago. Since then, Im not hearing anything, but Im feeling some stimulation through my head. Should I be concerned?
A: Johns Hopkins now has eight adults who had profound loss of hearing before age 5 but were implanted. It takes time for the brain to reconnect in order to give you the sense of understanding speech and more of a sensation of sound.
One of the first adults that we implanted that was deafened early in life said that he felt what was coming -- in his ears -- in his chest. Over six months or so it finally got up to the level of his ears. What that indicates is there is a lot of restructuring, a lot of reconnections going on in the brain. That can take a year.
Q: I was hard of hearing and then received a serious blow to the head which fractured my skull. One of my ears went dead overnight and the other was damaged badly. Could I implant the ear with the severed nerve?
A: The probe test would tell if that ear would be able to use the information from an implant. In most trauma cases like this, the nerve is still there but the inner ear is not functioning, so thats probably where the nerve got cut. The nerve itself should still be there and sensitive to signals.
Q: With two major but different implants, how do you decide which to use?
A: There are practical points to consider. Insurance coverage is one. The Clarion device was recently approved by the FDA for children as well as adults, so insurance companies will now reimburse for costs related to it. The new Nucleus 24 is still investigational so many insurance companies will not cover the cost.
If and when the Nucleus 24 is approved, then we have to compare the data from the FDA trials of the 24 versus the Clarion. We are very happy with the Clarion performance in our own patients and in our patients that were part of the FDA trial. Those results were much better than what the first Nucleus device produced. So we know that probably represents the best that is FDA-approved right now -- the Clarion.
Q: What are the recent improvements in implants?
A: The Nucleus 24 offers an ear-level processor that will be available in the middle of 1998. The Clarion should have an ear-level processor about six to twelve months later. There should also be ear-level processors available for those with the older Nucleus-22 implants in about a year.
Q: What about the Med-El implant?
A: This Austrian device has been placed in 20 to 30 Americans. It is very good, but the company is small and some people have said they are concerned about that. They want their company to be there 20 years from now when there is a problem and they need some help.
All three devices -- Nucleus-24, Clarion, and Med-El, use the very fast processing strategies that give the chord effect.
Q: How does the ear-level processor compare with the belt-worn ones?
A: The Nucleus-24 ear-level processor is available on investigational basis because its part of a study and can only be used for two months. Six months later you can get it back. The information from 40 people in the study shows little difference between the ear-level and belt-worn processor for the Nucleus-24. The belt-worn processor might be a little better.
The Clarion poses some difficulties for ear-level processors because its very flexible. There are three or four programs, compared to just one for the Nucleus-24.
Q: Are the processors today using Intel chips?
A: No, most implant processors today dont use the same level of technology as the desk top computer. That should change quickly.
They are not Pentium chips as yet, although the need may eventually come up for that. You have to realize that we cant put a desk top computer on your belt or at your ear. One very big problem is simply power. You would have to push around a car battery to run a computer of that magnitude.
Q: My hearing loss is service-connected. The Veterans Administration has offered to do the implant operation for free. Could I have the operation done at Johns Hopkins?
A: That depends on where you live and whether there is an implant program in place at your local VA. Johns Hopkins has done several implants for veterans.
Q: If I get the implant, would I be jeopardizing VA benefits?
A: People benefit greatly from the implant, but they are still functionally deaf. If the device breaks down, when you take it off at night to sleep, or when you shower or swim, you are deaf.
We have not cured the condition, only provided you with a very valuable assistive device.
Q: A lot of money goes to implants. What about the money that needs to go to research of how to fix the ear?
A: Johns Hopkins has a budget of $25 million per year for hearing research through the National Institutes on Health.
We are making good progress learning how to prevent ear cell loss. The real key, as many of you know, is when can we regrow hair cells?
These cells are so specialized, they are so dedicated to hearing, that to take any cell and try to transform it into a hair cell is next to impossible in a mammal like you and me. We can do it in birds, but birds have a relatively high range of hearing in higher frequencies, and their hearing is not specialized for speech, as our hearing is.
Q: Do you think cochleas will be transplanted from one human donor to another?
A: A lot of this goes to the very specialized function that our ears carry out, and when you ask a human organ to carry out that kind of task, to take tremendously complex information contained in speech to break it down and put it back together at the brain level to understand speech -- to get an organ like that to transplant successfully, we just dont know how to do it.
We can do okay with pancreas and kidney and hearts and things like that where there is sort of mechanical filtration or mechanical movement, but to take information and translate it and then put it into a code that the brain can understand is very complex.
Q: Is any work being done in cochlear transplantation?
A: No. A lot of research focuses on hair cell regeneration.
If we could regrow the hair cells, we know that the nerves would highly likely connect up to the hair cells and then the hair cells, as they jiggle, would send the information to the brain.
Q: I belong to an HMO. Are they willing to pay for implants?
A: Thats been an issue for some of our patients. For example, I showed you the study that we conducted that 14 patients couldnt get insurance coverage. Well, that was with their first request.
Now, of those 14 patients, all but one have received coverage, although they had to fight for it. Our policy has been to provide the insurance company with the results of the studies. They have found in many cases that this is valuable information and the surgery is worth their health care dollars.
Q: How should a patient shop for an implant physician?
A: That question depends on the individual case. Most of the 200 implant centers in the U.S. can help the adult with slowly progressive hearing loss who gets an implant. But for those with long term deafness or children, a bigger commitment is needed from an implant center to provide good rehabilitation.
What we are burdened with at Hopkins, quite honestly, are children coming in with little or no benefit, and we realize after talking to the family and to their audiologist and educators, that there is very, very limited understanding of what the implant requires, particularly for congenitally deaf children.
We take all those kids in and believe on the average that two years of rehabilitation is needed for children.
We have taken those kids in, but we have been reimbursed very poorly for that. And I dont mind that personally, but my hospital says to me, we cant continue to do business this way. I mean this is an expensive program that we have, and in our program we have eleven people dedicated to cochlear implantation, all of those people work hard, they deserve salaries. We take up a lot of space at the medical center, which costs money.
Q: What would be the commitment required to get a cochlear implant in time required for tests, etc.?
A: Johns Hopkins does two implants a week now. There has been an attempt to make the system efficient so there is no long delay between contact, placing the device, and activating it. You can probably expect three visits before surgery, and over the six months after surgery, probably four visits. Then once per year after that.
*Copyright 1997 by Northern Virginia Resource Center for Deaf and Hard of Hearing Persons, 10363 Democracy Lane, Fairfax, VA 22030. We strongly encourage you to share this information, but please be sure to credit NVRC.*