 Professor Jona Kronenberg. Photo: Bethsabée Süssmann |
The term “Cochlear” has come into current usage, often without us knowing what exactly it is. Can you briefly tell us what this technique consists of?
When the benefits of electricity were first discovered, that is in Volta’s time, he demonstrated that electricity could provide humans with the possibility of hearing. The program for implanting a Cochlear system (from the word cochlea, a part of the inner ear where the hearing receiver is located) is the first that facilitates recovery of one of the five senses that has been destroyed. We are hoping that this experience and the knowledge we obtain from an ever-increasing acquaintance with this technique will allow recovering other senses, particularly vision. Thanks to ongoing research over fifty years, the Cochlear implant is constantly being improved. Today it is available for children born deaf, and this discovery changes their entire life.
What exactly does the implanted device consist of?
It’s a small computer that can transform acoustic energy into electricity, which is then transmitted by an electrode to the acoustic nerves and to the brain. For the latter it is not important to know if this stimulation was transmitted to it by a nerve or by an electrical source. On receiving the impulse, the brain can understand the command and transform this information into hearing. For someone who has already heard in their life this operation is quite easy. In children born deaf, whose brains have never had information about hearing, the process is much more complex, since effectively it is receiving information that it does not know what to do with. Since the brain is intelligent, it has enormous means to understand, to adapt, to react and finally to do what is asked of it, even if it had never done this previously. That is why it is extremely important to implant a Cochlear as early as possible in a child born deaf, for the younger the child is the more the brain is malleable and the greater the chances of being able to change it. This docility on the part of the brain is gradually lost with the years, which is why adaptation is much more difficult in a child from age eight onwards, and consequently for an adolescent, than for a baby. This technique is today used in most countries around the world. In Israel we started using it in 1989, and you should be aware that it is a very expensive treatment, each implant costing US $21,000, not to talk of the costs of surgery and of rehabilitation. At the beginning we could only implant a Cochlear with the help of a foreign sponsor, but gradually the government agreed to participate in the financing, which today is totally covered up to the age of 18. Adults must pay 2/3 of the costs. The implant can be done at any age into anyone whose health permits a surgical intervention. Our oldest patient was 81 years old. Today there are about 800 people in Israel with this implant, a drop in the ocean compared with existing needs.
The technique is very well known worldwide. What are you doing that is revolutionary in this field that makes your intervention unique?
The operation itself involves hollowing out a passage in the mastoid (a small protuberance on the lower, rear part of the temporal bone, behind the ear). This is a long, meticulous drilling work to be able to install an electrode in the inner ear. This is why the operation can last two or three hours. In 1999 we developed in Israel a different implantation technique for the Cochlear. We did not invent the principle, but we changed the method of implanting. Instead of emptying the mastoid bone, we go directly through a small tunnel to the middle and inner ear and install the electrode there. This operation takes only an hour, which lets us do four a day. This implant uses a lot of energy and the batteries must be changed daily. Our operating technique is also much less dangerous than the classic method, where the facial and olfactory nerves risk being touched. Unfortunately there are a lot of deaf people among the Jewish population. Israel is the number one country in the world in number of implants per capita of the population.
We are currently doing 22 – 25 implants per million inhabitants, which is significantly higher than in other countries. We are followed by Holland, where 20 are done annually. This also means that we do about 130 operations a year, 60 of them in my department, the others spread over three other hospitals in Israel. Strangely, my technique has not been employed at other medical centers in Israel, but has been in seven hospitals in Europe.
Is this good news that has been well accepted by the deaf, who should be happy to know there is a fantastic way of curing them and removing their handicap?
Not at all. The world is divided into two groups: hearers and non-hearers. The deaf community is extremely closed in and possessive and looks very badly on the fact that some of its members leave it. You should be aware that the deaf do not consider themselves invalids; they have their own rules, and their social and communal life. They consider themselves slightly different, with a different way of communicating than the world of those who can hear. When we started, we encountered a lot of opposition from this society, which quite simply told us, “Why do you want to change us? Is it simply because you think we are inferior because we do not hear and we do not communicate like you?” There is a big difference between a group of the blind and of the deaf. The deaf are very happy among themselves and it is not rare to see them telling jokes, laughing and being full of vitality. This is because they adapt their handicap to their life style. Once I gave a lecture to a deaf group. After the lecture a man came up to me and said, “I am more intelligent than you, more pleasant than you and above all happier than you. Why do you want to change me? If you were to find a way of bleaching all the Negroes in the world, would you start up a large-scale surgical operation? Certainly not. So leave us alone”. At the entrance to the lecture hall, sheets had been distributed denouncing us as “the murderers of the deaf community”. At the Sorbonne I had an even more disagreeable experience. A dozen deaf people had taken places in the auditorium and when I started speaking, they took out umpires’ whistles and started whistling with all their might. This dreadful noise did not disturb them at all, but the rest of the audience ran fleeing from the hall! I was in Paris for an international conference on deafness. One evening, a concert had been organized for us at Notre Dame. On arriving I noticed that there were some twenty deaf people sitting on the stage, and I thought to myself that they were going to do a silent sit-in. An artist had come to sing a Bach oratorio. After five minutes, they took out their whistles and started “their concert”, terrifyingly amplified by the superb acoustics of the famous cathedral… which emptied in less than five minutes. The police did not intervene, because according to French law they cannot tackle invalids. Thus we are in a paradoxical situation where when it serves their purpose they invoke their being invalids, but at the same time they consider themselves to be normal but slightly different. Having said that, they are gradually starting to accept us, even though a large number of them are still totally opposed to our involvement. Incidentally, we had the greatest difficulty implanting a Cochlear into a child whose two parents were deaf. But we have had cases where we have implanted Cochlears in five members of the same family, for both parents and three children. Little by little they understand that we are not hostile to the deaf community, but that we are working to make their lives easier.
With our technique we can not only change the lives of children, but also of adults who have lost their hearing for one of many known reasons, including viral infections. Such a loss can happen gradually or suddenly following a violent trauma. In Israel the largest number of cases of deafness is not due to the wars or terrorism, as one might have thought, but to viral infections, followed by those born deaf on account of typically Jewish chromosome disorders, among both Ashkenazim and Sephardim. Another type of illness, more frequent in Chassidic circles, results from intermarriage. Strangely, and for the same reasons, this phenomenon is also to be found among Arabs.
The Cochlear implant is clearly not the end of hearing problems, and complete education must follow. How does this happen?
We install, according to the case, between 16 and 22 electrodes. Each one has a predefined function for the tessitura in the cochlea and the computer transforms the acoustic energy into electrical energy. We therefore have to program the computer for each person. Then the difficult learning period of recognizing sounds and noise management starts. It is not just a matter of listening and hearing, but also of knowing how to talk. The patient discovers a whole new world, and I remember one who once told me, “I never knew that when I write, the pen on the paper makes a slight scratching noise”. There are three categories of patients: children born deaf, adults who have lost their hearing and adults born deaf. The best results that we obtain the most easily are from the second group, because the brain already has the information about sound management and we just need to reactivate it. Children born deaf must learn everything from the beginning. With adults born deaf the difficulties are enormous, in fact they never learn to hear words or to speak, they can only hear noises, like a car or a child crying. Their brain is simply not in a position to put together the different elements of the sound to extract the words. The capacity to learn to speak begins to decline from the age of eight, which is why it is very important to do the implant when the child is as young as possible. Having said that, even if the chances that an adolescent or adult born deaf could hear properly are minimal, despite that we still do the implant: on the one hand this gives them the feeling of being connected in the most important way to those around them, and on the other hand just being able to hear certain sounds might save a life, for example hearing a car coming and getting out of the way.
Can you give us an example of one of your operations that touched you especially?
A few years ago a bus full of soldiers was attacked by a terrorist at Meron in northern Galilee. One of the victims, a young soldier, lost both his eyes and his hearing. When he came to and realized what had happened to him, he was deeply shocked. A friend had the idea of giving him letters made of plastic, and by touching them he would gradually be able to form words. Thanks to this slow and difficult process he was able to communicate. When he came to me I straight away implanted a Cochlear system in one ear. He re-learnt hearing and today he hears normally from that ear. He can even distinguish the various people talking to him if he knows them, and he can tell from their voice if for example someone is hoarse or has a cold. Recently I implanted a second system in his other ear, a difficult operation because after the attack almost the entire inner ear had been destroyed. Today just being able to speak to him is a fabulous source of hope, and he is full of life and optimism. Unfortunately for the time being there is no solution that will let him recover some of his sight.
How are the Cochlear and your technique going to develop?
Our first objective is to improve the quality of existing devices. Even if we have so far recorded a certain number of successes, there is still a big difference between natural hearing and hearing with the aid of an implant. It is particularly important in a noisy environment and we want to reduce this difference. Our second idea is to further reduce the size of the implant itself. Many patients are afraid that this device will significantly change their child’s physical appearance. This idea implies that the implant be fully miniaturized and that the battery need not be changed but just recharged. In a word, the person could just connect themselves to a charger, like for a cordless telephone. This idea is coming about and I think that within five years it will be in regular use. In the future this technique will certainly replace hearing aids and let those with only a slight handicap hear much better. This technology has enormous development potential, even though research in this field is not really being currently carried out in Israel.
We see the amazing work of Professor Jona Kronenberg and his team, which provides increasing relief to the community of the non-hearing. In him we can see the true measure of an old adage, “You have to listen to be able to be heard!”