CC >> We'd like to move onto a few
research presentations. And what I'm going to do is
begin by telling you a little bit about what we think of as
some of the recent advances in cochlear implants, but also
there are future possibilities. I always like to think of the
work that we're doing in the community, and when I say
community, I mean the field of cochlear implants which spans
worldwide. I'd like to think of the work
we're doing as representing the glass being both half full and
half empty in the sense that we've made tremendous progress.
We've learned so much about how to provide hearing to people who
are either born deaf or acquire deafness later in life, and yet
there are remaining challenges. You'll hear me talk both about,
look, this is what we're finding, and this is really
fantastic progress, and you'll hear me talk about, this is
where these children or these adults aren't functioning as
well as normal hearing people. And it's important to think
about that bar. As Dr. Heatley described through
the history of cochlear implants, initially the goal was
to provide access to sound. I know there's sound there.
Or access to some speech and language.
The field, we always compared people to people who have
hearing aids but who have severe to profound hearing loss.
So the question was whether cochlear implants are doing a
better job than hearing aids for that same population of people.
Today we've changed the bar, we've raised the bar, we've
changed the goals, and we talk about the desired outcomes as
being equalizing, people who have cochlear implants with
people who have normal acoustic hearing.
We hope down the road this is what the devices will be
able to do. We talk about possibilities for
future development, this is what we're aiming for.
So you've heard from Dr. Heatley about some of the history of
cochlear implants, which is that we wanted to create devices that
could provide access to sound. So that the user could
communicate with verbal/oral communication, and not have to
be necessarily, although some users are bilingual, in the
sense that they use sign language as well.
You've seen that the age of implantations that decreased.
When I was first working in the field most of the children I met
were receiving their implants no younger than age 3 or 4, and
today we see many children receive them during infancy.
And the criteria for implantation has changed in the
sense that people used to be severe to profound, whereas
today we see people who have quite a bit of residual hearing.
Sometimes in the ear that gets implanted, but there's new
devices out there that are hybrid in the sense that we
provide a short array, so a partial cochlear implant in an
ear that is also receiving acoustic hearing.
Some people have very good residual hearing in the low
frequency area, and to preserve hearing in that area, there's a
new short array that is being tried on quite a few patients to
preserve hearing in the lower frequencies, and to combine
acoustic with electric hearing in that ear.
That is a hybrid device, and we also have people who are
bimodal. If you have serious, severe to
profound hearing loss in one ear, but good residual hearing
with useable acoustic hearing through a hearing aid in the
opposite ear, you're a candidate for bimodal listening.
You can be bilateral, but bimodal.
There's a very small number of patients worldwide, and this is
under serious debate, who have excellent hearing in one ear,
but deafness the opposite ear.
These are single-sided deafness people.
Especially in Europe, they've implanted quite a few dozen
people, and it's off the FDA label, but there's a handful of
patients in the United States with single-sided deafness who
would like to have hearing in the deaf ear.
Often it's to relieve tinnitus. But there are a few people who
don't have tinnitus who are interested in getting that
device as well. I'm giving these examples to
highlight this very important point which is that the criteria
for implantation is changing, and it's continuing to change.
I'm always surprised at what I see at the next conference I go
to. A new candidate, a new
population of people who seem to be benefiting from these
devices. One thing that Dr. Heatley
didn't really get into, but I think is important to mention,
is that when people are not candidates for cochlear implants
because we cannot stimulate the auditory nerve, there are
devices that can be implanted more centrally in the brainstem.
There are auditory brainstem devices, and there are now
slightly higher devices that are going into the mid-brain.
All of these are experimental, but there's a growing number of
patients, always more in Europe than in the United States,
little bit looser criteria surgeons who are a little bit
more aggressive at trying out some of these procedures, but
they end up coming back to the states at some stage, and we'll
see a growing number of those as well.
The other thing that is very interesting that we've seen, and
I show a picture of this family here.
This is a wonderful family who have traveled to Madison from
far away from the west coast that participate in our research
program a number of times. And the reason they're very
interesting is that both of the parents who are congenitally
deaf grew up speech reading and using sign language, and both of
their children were born deaf. They decided that their children
should have cochlear implants right away as soon as they were
able to do that, and in fact both children were implanted
bilaterally, and in fact each parent ended up getting a single
cochlear implant as well. So six implants in that
household, which is very interesting and wonderful
management. They do beautifully.
The children both speak and sign.
What's interesting is that they're growing up in a
household where the parents' speech isn't that
well-articulated. They grew up deaf, and they do
very well being mainstreamed, but their speech production is
not what I would say, very clear.
Yet the children's speech is outstanding.
I think it's a testament to the speech therapy that these
children are receiving and have received since the day that they
could benefit from it. They're a wonderful family.
Very supportive of the cochlear implant as a means of providing
oral, verbal communication. I think this transition in the
field of seeing more and more adults who is decided later in
life to choose to get a cochlear implant is something that we
didn't see 10, 15, 20 years ago either.
So I'd like to tell you a little bit about what the field has
shown, and then move into some of the research that we're doing
here at the Waisman Center at the University of Wisconsin.
In general in adults who receive cochlear implants, we see
differences between people who have onset of deafness, either
congenitally or early in life. This came up a little bit in the
questions a few minutes ago. People who have onset of
deafness during childhood, and people with onset of deafness
during adulthood. It seems, moving up from the
bottom of the slide, that the best outcomes in the sense that
immediate recognition of voices at the turn-on of the devices
are people whose onset of deafness is during adulthood.
Sometimes people report that at turn-on they can understand
their spouse's voice, or at turn on, they can understand speech
and recognize music. Sometimes it takes a few months,
but not that long. As we move up into the domain of
people with onset of deafness congenitally or early in life,
this is where it takes longer to see the benefits, and sometimes
the benefits don't get as high as for people with onset of
deafness during adulthood. This has almost everything to do
with what happens to the auditory system when it's
deprived of stimulation. This is why when we talk about
children, we talk about early stimulation being very
important. Adults who have spent many
years, as we think of them being out of sound, have experienced
degeneration in the neural circuits.
What that means is that neurons lose the ability to send
information to the brain. That is not something we can
recover. We can recover the ability to
use whatever information we have, but when the neurons can't
stimulate anymore, or there are fewer of them, this is when
getting information through the cochlear implant becomes more
challenging. So through the fields,
through hundreds of labs and research papers that have come
out, this has been a consistent story between the age of onset
of deafness and the amount of time being out of sound is
important factor in outcomes. In children we see a similar
story, but there's more opportunity for plasticity in
children. We see with children born
congenitally or early in life, early implantation leads to
greater success, which is why the age of implantation has come
down. Children with onset of deafness
during early childhood also see excellent success.
Sometimes they need more speech therapy.
Sometimes it takes a little bit longer, but there are other
factors that add to the variability that we don't
understand yet. So today's standards, we implant
early and/or soon after we see that they don't get much benefit
from the hearing aid. I want to get into the nitty
gritty of the research that we know from the field.
One of the first questions is how do we test these kids.
How do we know what they're hearing or what they're
understanding. I wanted to show you a little
video in which I can give you an example from our research
domain, but it's not that different from what we do in
the clinic in how we test language abilities in very young
children. You're seeing a video of a young
toddler. Actually, he was wearing
body-worn devices. The little wires are hanging
from behind his ears. He then got the ear level
devices about a year later. This in particular experiment,
which was done by Tina Grieco-Calub, who was a
post-doctoral fellow here, we were interested in whether a
child can look at pictures of words that the parents tell us
they know. So the child knows the word
baby, which is pictured here, or dog, doggy, which is pictured
here. But the question is when they
see these pictures in the real world can they hear the auditory
information and match that auditory label to the visual
object. So how good are they at in the
real world or in the lab real world scenario can they do that
task. How accurate are they, and how
fast are they. So let me play this little movie
for you. What I want you to do is watch
the baby's eyes. In the data analysis we score
30 frames per second where the baby's eyes are moving.
He's darting around the room. I'll play it twice.
Before the sound comes on he's just looking around.
After the sound comes on his eyes settle somewhere in the
room. So watch his eyes.
Look at the doggy. Where is it?
Oh-oh, the sound didn't come on.
Should we turn it up a little bit?
Look at the doggy. Where is it?
I'm going to turn it up again.
Here we go. >> Look at the doggy.
Where is it? >> Hopefully, what you saw, she
said, look at the, but after she said the word doggy, his
eyes settled on this part of the room which is where the
picture of the dog is. Each kid does that many, many,
many times. We alternate sides and pictures,
and then we score the data for all the children.
We also do this in the presence of noise.
So they're listening to the woman, but there's a male voice
in the background. Let me turn this down in case
the too loud. [indistinguishable male voice]
Female voice: Look at the doggy.
Where is it? >> So the male's voice is
actually ten decibels below that of the target female voice.
For normal hearing people that is a no brainer.
Plus ten decibel signal to noise ratio is very easy.
But let's see what happens with these children.
So what I'm showing you, the data, are the proportion of time
that they're looking toward the correct target location as a
function of time. Now over here at the top what
you see are data from children who are normal hearing when
they're listening and quiet. What happens is as soon as the
word doggy comes on or baby, depending on the target, their
eyes dart to the correct location.
And they're almost one hundred percent correct.
So they're fast and accurate. When we play the stimulus of
noise, these normal hearing children drop.
When we test children with cochlear implants, that's the
filled triangles, they look like the normal hearing children who
are listening with noise or maybe even a little bit worse.
Remember, these are two and a half year old children.
Children with cochlear implants have had less exposure to sound
because they didn't get their cochlear implant until 12 or 18
months of age. They might be a year behind or
have had a year less of auditory experience than the children who
have normal hearing. So in a way they're doing pretty
well. On the other hand, when they're
listening and quiet, they look like the normal hearing kids
listening in noise. To answer that question that
someone asked about, what's it like to hear with an implant
when you're first turned on. People report that it's a noisy
system, and it takes time to get the clarity of the information
from the cochlear implant. Maybe six months or a year isn't
enough, and they need more time, which is why it sounds noisy to
them early on. But they can do the task.
I think the glass is half full part of the story is, my
goodness, they can do the task. They sit there, they do it,
they're learning the words. Yes.
Just a clarification question, bilateral or
unilateral? >> Good question, the question
was are these children bilateral or unilateral.
The answer is that in this study we tested many bilateral
implanted and unilateral implanted children, and there
was no difference on this particular task.
But one thing, since you asked, is that the target speech and
the noise both came from in front of the child.
One thing we know about from having two cochlear implants, is
that they specifically might be able to help us if we separate
the target from the noise. That was not done in this
experiment, but we're currently doing in our lab in that sound
booth that you've seen down the hall.
So hopefully we'll know the answer to that shortly.
I had that on here. Children with one implant
perform as well as children with two.
Now as they get older, many children with cochlear implants
catch up with their normal hearing peers in terms of their
language abilities, but not all. Again this is the glass is half
full, and half empty part of the story.
These are data from a paper published a couple of years ago
from a very, very large project that was managed by Dr. Niparko
and his colleagues from Johns Hopkins.
It's a very extensive paper. If you're interested, I highly
suggest reading it. The basic part of the story is
that the children who have normal hearing have a hearing
have a mean trajectory of language outcomes that's
up here. The mean trajectory of children
with cochlear implants is down here.
And this is what they were like before they got their device.
You can see that they're closing the gap toward the kids with
normal hearing, and that quite a few are following the trajectory
of the kids with normal hears hearing.
Yet there are a number of kids who are staying down here.
This continues at other ages and other intervals of testing them.
You can see that these are the children with normal hearing
when they're older. Children with cochlear implants.
Some are closing the gap, and some are staying down here.
And so most of the children in that study were implanted
unilaterally. I'd like to now move into
bilateral cochlear implants, and start to get at some of the
research that we're doing here in the lab, and ways that we
think that bilateral implants may be able to help close some
of that gap. As Dr. Heatley also mentioned,
providing implants in two ears has now become a standard of
care in many clinics around the world.
Now the goal initially was to provide hearing and maybe
replace the other ear. But into the '90s, and into the
last decade or so, the goal was to try to bring them up to where
normal hearing people are who have normal binaural acoustic
hearing. What do we get from having
access to sound in both ears when we have normal hearing?
Well, the goal for the children with cochlear implants was to be
able to mainstream them, to make hearing easier, but
specifically binaural helps us hear noise, and to know where
sounds are coming from. Many of the people who have
bilateral implants report a significant change in the
quality of life. It's easier to listen.
I see my child is less tired. I have an easier time
functioning in the real world, and you'll hear about this at
the patient panel as well. We recently looked at 45
children who have bilateral cochlear implants, and we looked
at language outcome measures, some of them very similar to the
ones in the Niparko study. They were slightly older.
What we looked at, and I'm just showing you a little bit of the
data, was a non-language measure, a brief non-verbal IQ,
and some core language measures. The first thing I want you to
notice is that this bar is the mean, the average, of the normed
population in the country of the children at that age.
What you can see is that the kids who are coming to
participate in our research are coming with parents who have
very interested in supporting the research, and have the time
and the ability to come here. These are very smart kids.
Their brief non-verbal IQ is hovering not just around
average, but very high, one or two standard deviations above
the mean for the majority of them.
In terms of language scores, when we first test them we see
that many are within one standard deviation of the mean,
and some are below the mean. Then as we follow them up, I'm
regraphing the data, but what I want to show you is that
the brief IQ as we follow them, the blue bar is the first time
we tested them, which I just showed you in the last slide.
A year later is the red bar, and another year later is the green
bar. The brief IQ stays the same,
hovers above average. Another measure that's not
language related, a memory screen is also above average.
What you see with the language is that they're getting better
on average. As they're getting more
experienced with their implants, their core language, their
ability to listen or speak, is coming up at or above the mean.
This is where the glass is more than half full because these
kids are getting more experience, and catching up or
surpassing their normal hearing peers, which achieves one of our
goals which is to be able to mainstream these children with
oral/verbal communication. Oh, my goodness, what happened
to my slide? Oh, I see.
Okay. Something happened to it.
But I can still talk it through. So the other thing we're
interested in is specifically binaural hearing which we know
is important for the what question, can you understand
what I'm telling you, and the where question, can you tell me
where sounds are coming from. We do this because when we have
sound arriving at both ears. Say we have sound coming from
there, the sound reaches the ears at different times, and
with differences in intensity or level.
And the brain is doing a beautiful job of calculating
those differences and being able to help us understand what in
noise other where sounds are coming from.
This is an example of something that's been studied over the
years even with normal people, with something called the
cocktail party effect. I'll sitting in the room full of
people, they are all talking at the same time, I'm trying to
focus on what one person is saying, and ignore what others
are saying. How can I do this?
Binaural hearing helps us do this, and the hallmark of
binaural hearing is what we call is source segregation.
What we're trying to do with people who have bilateral
cochlear implants is improve their ability to do source
segregation. So the way we do this in a
research environment is that we position somebody in a room with
loud speakers, and we're simulating a realistic listening
environment. What we ask them to do is either
tell us what they hear, so we might present sounds from
different locations or where they hear these sounds.
We do this with noise in the background or we do this in
quiet. I want to show you a tiny bit of
data from the work that we were doing.
Here I'm showing you sound localization.
So can you tell me where the sound is coming from.
But they're listening either in quiet which is over here or in
noise. Now this number here represents
how bad they are. How many mistakes-- on average
what's the error in degrees. If the sound is coming from over
there, but you tell me it's over there, you made an error of
30-degrees. How good are you at solving this
problem. What we're finding is that in
quiet adults with bilateral implants rock.
They are doing an incredible job of knowing where sounds are
coming from in quiet. This is what they do with a
single cochlear implant. This is the benefit then of
having two cochlear implants. So these are the unilateral
errors and bilateral errors. Now normal hearing people, as we
add noise, and make the signal to noise ratio worse and worse,
normal hearing people are holding out fairly well.
Steady rise in error, but not too bad.
What we see with people with bilateral implants is that their
error rates rise dramatically in noise.
Why is this important? All the studies on sound
localization with bilateral implants, that sing the praises
of bilateral implants, are done in quiet.
And it's beautiful in quiet, right?
One implant versus two is a significant improvement in sound
localization. When we put people in noisy
environments, this is where having bilateral implants isn't
as good as we want it to be. Why not?
What I'd like to do is take a minute to tell you what we're
looking for in terms of future progress.
What happens with two cochlear implants is that we put them on
clinically, but we fit them as if we're fitting two ears
independently. Is there anybody to blame?
Not exactly. The manufacturers are working
hard to miniaturize them, make the device better, faster.
But what they haven't spent time doing is figuring out a way for
the audiologists to map the devices bilaterally or force the
devices to talk to each other. In a normal acoustic system, the
ears are talking to each other right away, two synapses away
from the cochlea, there's integration of inputs in
the brainstem. Right ear, left ear, a couple of
milliseconds, and the information is in the brain.
With the bilateral implants that is not happening because we
haven't done the engineering properly to do that.
So are they doing better than with one implant?
No question. We also have data for speech
and noise showing that they're hearing in noise is
significantly better with two than one.
Have we closed the gap? I think there's still work to be
done there. I have a couple of minutes
for questions. I'll be here all day and I can
take more questions throughout the day.
Thank you very much for your attention.
[applause]