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Or you have a loud hearing aid on, things are fuzzy. There is no way this can be made
any clearer. That is one of the limitations of hearing aids and one of the reasons why
we keep looking for better ways to deal with this. The cochlear implant has become the
standard device for people who are nearly deaf or do not benefit from hearing aids.
It requires a surgical procedure. Medicare pays for it. It’s become state of the art.
In the upper left you see the inner ear with the wire curling around that is surgically
implanted. And the young lady shows the attachments that fit over the ear, where the sound comes
in through the microphone, through the skin, and directly to the hearing nerve. These work
beautifully except for with music. It is very difficult to understand pitch and words in
a musical song. This is being dealt with in some of the newer aids. These devices cost
about $25,000. It costs another $10,000 for the surgery and the programming so they are
not cheap but they have become Medicare funded devices. [pause]
Before we get down to what’s coming down the pipe, I want to emphasize communication
courtesy. Many people could improve their communication if they just followed these
suggestions. So if I am trying to talk to you, I want to look you in the face. I don’t
want to do this because you can’t see the way my mouth is moving, my expressions. So
if I had one word to say to spouses: “if you want your husband to hear, look him in
the face.” Now I have high frequency hearing loss and I do just fine in quiet but when
my wife is doing the dishes and looking at the sink and I am in the next room looking
at the television, we don’t communicate. So I tell her that if I can’t see her face,
it doesn’t count. She can say whatever she wants but if we are not looking at each other
it doesn’t count. Turn off the TV. That is why I wish I could make this room suddenly
quiet, you could hear me a lot better. For you as a listener with a hearing loss, pay
attention. You can’t do this casually. If you work at it you will hear better. Don’t
be afraid to say “well dear, I thought you said you wanted me to take out the trash tomorrow
or did you mean right now?” You get feedback in everything that you do in life. Why not
do it in communication. Repeat the message and for god’s sake don’t pretend and don’t
assume that what you heard was what was said. Don’t be frustrated because your loved ones
are probably going to be more patient with you than you deserve because they have a vested
interested in getting their message across. Otherwise, the trash won’t get taken out.
[pause] So, let’s talk about the hot new topic,
hair cell regeneration. I would like to spend the rest of my time on this. But before we
move ahead, if anyone has a question on something we said you can come to the microphone and
we’d be happy to visit with you. As I say, I’ve heard this talk before so I don’t
mind being interrupted. [pause]
In this type of research we use mice, chickens, and the latest players are little zebra fish
down in the bottom. The green spots are the hearing mechanism of the zebra fish. They
hear with their ears and also the lateral line structures. They are wonderful for doing
auditory research. Now, hair cell regeneration is not yet here but if I have anything to
say about it, it will be here in the next 5 to 10 years. But it is going to take a concerted
effort by the citizens of the country to influence congress to say that we need this to come
to pass. These are the steps that we have envisioned. Right now, we are in step 2. The
proof of concept came when two different investigators discovered that birds would re-grow their
inner ears all by themselves without any help. As a result of that, the hearing and balance
function came back. Why do birds have such great ears? Maybe they depend more on hearing
than we do for flight and bird song. Here is the inner ear of the bird. It is not coiled
around like ours are but the hair cells are just the same. This is a normal inner ear
of a bird.
Here in a cross section you see the hairs sticking up and the supporting cells underneath.
Here is a closer view of the hair cells. They are all alike and they are all neatly packed
in place. Here we are 6 hours after exposure to a loud sound and you see that the pattern
has been disrupted in this area in the center. The membranes have been lifted up. The cells
have gotten made into little balloons and they are dying as fast as they can do it.
And in a week or so you will start seeing little baby hair cells pop up where the arrows
are and in 30 days the ear is completely regenerated, completely back to normal. It works because
the supporting cells (in the redish color) are stimulated to divide. Normally in life,
your inner ear cells don’t divide. What you get at birth is what you end up with at
death. Nothing happens through our lifetime. And they [chickens] divide and begin to form
new hair cells and new supporting cells.
So, what’s wrong with us? That’s the question. Over the past 20 years, there has been a lot
of research aimed at identifying the factors that we lack to get us going. Or the factors
that are blocking it when this starts to happen. So we can take out cells, say from the mouse
and put them in culture dishes and add various compounds and see which ones make the cells
grow. In doing that, we have a list of agents that take part in hair cell division.
This shows some of the marker dies that can be used. In the bottom pictures you see after
a drug has been used to damage the tissue, the little red spots have gone down by 50%.
I mentioned earlier that cells don’t dye all at once. If they are stimulated by the
aminoglycoside antibiotic at the top they might. There is a cascade of biologic signals
that take place before the cell actually dies so we can block this process. We can prevent
cell death and if we can reverse it, we can bring some of them back to life.
Here is our little zebra fish. We put a little compound called DASPEI in the tank and it
stains the hair cells and then we can test various compounds to see if they make the
hair cells grow or prevent them from dying. The beautiful thing about these is that they
are barely half an inch long and you get…