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EHDI CONFERENCE
Audiology 101 -- Introduction to Audiology for Non-audiologists Working in and
Supporting EHDI Activities
2:00 P.M. - 3:00 P.M. (ET)
FEBRUARY 27, 2017
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>>SPEAKER:
Well, good afternoon, everyone.
Welcome to Audiology
101, which is an introduction to audiology for non-audiologists working in and
around EHDI programs and supporting EHDI activities.
I'm Jeff Hoffman with
the National Center for Hearing Assessment and Management.
I want to
introduce my co-presenter.
>>DR. FOUST:
Good afternoon. Sorry about that.
I'm Terry Foust, and I'm a pediatric audiologist and speech language
pathologist, and I've been a consultant with NCHAM's Early Childhood
Outreach programming project and based in Salt Lake City, Utah, and I'm
happy you elected to join us after lunch, and we appreciate your attendance.
>>MR. HOFFMAN:
So at the end of the next 60 seconds we hope that
you'll be able to -- is this better to hear me?
Is that better volume?
Okay.
We hope that you'll be able to identify the parts of the auditory system,
describe how the ear works.
I can do this.
I can do this.
Describe the types and degrees of hearing loss.
Describe how hearing
loss is assessed and diagnosed as well as describing the types of treatment and
intervention that's available for hearing loss.
We're going to start by just a very brief overview of what audiologists
are.
Audiologists are specialists in hearing and balance, and you know, one
aspect of the work is in the prevention of hearing loss -- the identification, and
assessment of hearing loss and balance problems and then in the rehabilitation
or habilitation in persons with hearing and balance disorders.
With the EHDI programs with newborn hearing screening most of the
focus -- in fact all of the focus is on the hearing aspect rather than the balance
aspect.
This is a cross section of the ear.
And we're going to go through and
look at the different parts of the ear starting from the outside toward inward.
So there are four parts to the auditory system.
There's the outer ear, the
middle ear, the inner ear and the central auditory nervous system.
So we'll start with the outer ear.
Whoops.
The part that we see of our
ear is called the pinna, and it's a fleshy portion, and it really doesn't do much.
It's great to accessory eyes sometimes but not much to do with hearing.
The
external auditory canal, also called the ear canal is funnels sound towards the
auditory system, and it's about an inch long, and kind of S shaped, kind of
curved.
And at the end of the outer ear portion, the end of the ear canal is the
similar pan nick membrane or eardrum, and that serves as the boundary
between those two parts of the auditory system.
eardrum.
This is a picture of the
You'll notice that it's -- this is a healthy eardrum.
pearly gray color.
And it's somewhat translucent.
It's kind of a
You can barely start to
see one of the ears of the middle ear bone here.
Wow, that is supposed to be a pointer, but it's not working.
So in the center up to about the 1 o'clock position on that eardrum is
where the -- one -- the bone to the middle ear is attached to the tympanic
membrane.
The next part beyond the eardrum is the middle aerospace.
basically a cavity.
It's an air-filled cavity.
It's
And it contains three bones, the
smallest bones in the body, and we'll look at those in just a second, but those
bones serve to transmit sound to conduct sound from the ear canal that has
been con through the tympanic membrane, vibrated the tympanic membrane,
eardrum, and it keeps transmitting that sound forward, those vibrations and
the process the eardrum, and the three bones increase the strength of those
vibrations at that time are coming in and the sound that's coming in, the sound
energy that's coming in at this point gets trans -- transposed to a mechanical
energy, so we've got a transfer of energy there.
Another part of the middle aerospace, the middle ear system is the
eustachian tube, and that's a tube that connects that middle ear cavity to the
back of the throat, and it serves to equalize the pressure between our external
environment and that middle aerospace.
in the last couple of days?
So how many of you flu into Atlanta
A lot of you did.
Were your ears at some point a
little bit stuffy when you were ascending or descending?
Well, that's because
that eustachian tube hasn't yet opened up and equalized the pressure.
let's say you're landing, your ears are stuffy.
You know.
So
You chew gum.
You swallow, something like that, that opens that eustachian tube and
equalizes the pressure between the two.
Here's a picture of those three little bones in comparison to a dime.
They are the smallest bones in the body.
And from the left to right it's the
hammer, also called the malleus or the incus is the middle one, also called the
anvil.
And then the stapes or the stirrup is the smallest one there, and these
are connected by ligaments and they're also very, very small muscles that are
attached to them.
And those muscles can contract in response to loud sounds
and kind of stiffen that system up and prevent some of that sound from being
transferred on to the inner ear.
So it serves -- those muscles serve as a little
bit of a protective mechanism.
The third part is the inner ear, and this sat part that gets really
fascinating as far as all of the parts.
There are two parts to the inner ear.
One a part of it has to do with balance, and the other part has to do with
hearing.
So we're going to focus on the hearing part, and that's the cochlea
which is that little snail-shaped section that you see offer to the right of the
screen there, and it's fluid-filled.
fluid.
It's in the skull cavity, and it's filled with
There are three different chambers that are filled with fluid, and it
contains the end organ of hearing by is called the organ of corti, and it also had
many thousands of hair cells or sterocillia, and we'll take a look at those in just
a second.
So when that sound comes in through the ear canal, vibrates the
eardrum, transfers through the -- those bones and gets to the cochlea, it
pushes that fluid back and back and forth, and those little hair cells get bent
very slightly.
And as they bend, they generate electrical stimulus that then
goes on up to auditory nerve to the brain.
Here's a picture of the hair cells.
You'll see that there are three rows of
those little V shaped ones.
Those are the outer hair cells and then there's one
row of the inner hair cells.
Terry will talk a little bit later about one of the
hearing tests that has to do with those outer hair cells of the when they get
bent they produce an oat toe -- OAE, if they're functioning normally, and that's
one of the tests that are used in newborn hearing screening.
Another aspect of the hair cells is that their frequency specific.
Depending on where they are in the cochlea, they respond to different pitches,
to different frequencies.
And the fourth part is the auditory nerve and the central auditory
nervous system, and this -- the auditory nerve has more than 25,000 nerve
fibers, so it's once a again lots of little parts, lots of things going on when sound
comes in, and that auditory nerve transmits that electrical signal up through
the brainstem and to the level of the auditory cortex.
So now we've gone from a sound pressure to a mechanical to an
electrical signal, and then once it gets to the cortex, to the brain, that's where
we assign meaning to it.
are.
That's where we recognize what different sounds
So when I snap my fingers, (snap), we think that was a finger snap.
So
that's -- that's happening at the auditory cortex.
There's a really good You Tube video.
It's about 7 minutes long that's
called auditory transduction by Brendon Spletsch, and if you want to see a
really nice demonstration of how all of this works, take a few minutes
S-P-L-E-T-S-C-H, and I'll show it later, but it's kind of fascinating, at least for
me.
I hope you might find it fascinating to see how the ear works on that.
When we think about hearing loss, when we talk about hearing loss we
want to think about all of the different ways that we see can describe different
types of hearing loss.
The first way that we can describe hearing loss is by
how many ears are involved.
So if only one ear is involved it's called a
unilateral hearing loss.
If two ears are involved then we call a bilateral hearing.
We also can describe hearing loss by where in the auditory system
there's a problem.
If we have a problem in the it outer or middle ear, it's
called a conductive hearing loss because it doesn't conduct the sound.
So if
your ear canal is plugged with wax or, you know, Mardi Gras is coming up
sometimes Mardi Gras beads get put in kids ears or other things, that's a
conductive hearing loss because it's blocking the sound from being conducted
inward.
If a child has a middle ear infection that has fluid in that middle ear space
that also prevents that sound from being conducted on into the auditory
system.
So problems in the outer ear and the middle ear are called
conductive hearing losses.
There are two types of conductive hearing losses.
permanent ones and temporary or transient ones.
the fluid, those can be treated medically.
There can be
So the Mardi Gras beads,
The Mardi Gras bead which can be
removed, the wax, the fluid, and middle ear treated and that fluid resolves so
it's a temporary or transient hearing loss.
But if there are malformations in that -- let's say that there's atresia
where there's no ear canal, that's more of a permanent hearing loss until
there's a surgical treatment for it.
Another type of hearing loss is called sensorineural hearing loss, and
that's when there's a problem in the inner entire or in the auditory nerve,
and -- inner ear or in the auditory nerve and we have a mixed hearing loss
which can be a combination of both a conductive hearing loss and a
sensorineural hearing loss.
So that would be a problem in either the outer ear
or the middle ear and the inner ear.
So that's why it's called a mixed loss.
Both conductive and sensorineural.
And then we have hearing loss that's a result of problems in the auditory
nerve or in the auditory -- central auditory system, and that can be called
auditory neuropathy spectrum disorder.
It used to be called auditory
neuropathy dys-synchrony, and that has to do with disordered transmission of
that electrical signal along the auditory nerve.
And then the auditory system
processing disorder has to do more in the cortex area.
Every year the centers for disease control and prevention ask all the
early hearing detection programs in every state and territory to report certain
data that they've collected every year, and that data has to do with how
many -- has to do with the screening.
It has to do with the diagnosis, and it
has to do with the intervention that 1-3-6 that we've talked about that you've
heard about in the last day.
And these are -- these are only -- the only data that's getting reported is
called congenital hearing loss.
Hearing loss that occurs at birth.
We'll talk a
little bit more about later onset hearing loss but at this point in 2014, which is
the latest data that CDC has available, that about 40% of the babies who are
identified with a permanent hearing loss had a unilateral hearing loss, a
hearing loss in only one ear.
And then almost 60%.
There's some unknowns in there, too, so not
everything adds up to 100%, but about 60%, the most common type was a
bilateral hearing loss, a hearing loss in both ears.
Now looking at the type of hearing loss, only about 13% of the congenital
hearing losses are a result of problems in the utter ear or the middle ear, and
those are those conductive hearing losses so that's not as common.
The most
common one is the sensorineural hearing loss which is a result of problems in
the -- most often in the inner ear, in the cochlea, and that's almost 3/4 of the
hearing losses are sensorineural.
Mixed hearing loss is fairly rare.
Remember that's the one that has both
a sensorineural and a conductive component, and that runs at about 8% of the
babies who are identified with a congenital hearing loss.
And then auditory neuropathy spectrum disorder is also somewhat rare.
About 8% of the babies who are identified with hearing loss at birth had
auditory neuropathy.
The incidence is a -- is greater for babies who have
been in the NICU than for babies in the well-baby.
This is all combined,
though for about 5%.
As a result of all of the data that CDC collects, we can start to look at how
common is any type of hearing loss in the birth population, and -- this is -- all
of these stats hold fairly steady from year to year.
There's a little bit of
variation, but about 1.6 of every 1,000 births, there's a permanent congenital
hearing loss that is identified at birth.
It's the most common birth condition.
And then as you've probably become aware of, there's an issue of loss to
follow-up, loss to documentation in the EHDI system.
Babies that don't get
the follow-up diagnostics or they got it and it didn't get reported, and that's
about 25% of the babies who didn't pass the newborn hearing screening.
So
actually the incidence is probably greater than that 1.6 because we have that
missing group over there, that 25% that we don't know about of the babies
who didn't pass that initial newborn hearing screening.
Hearing loss just doesn't happen at birth.
span.
It happens across the life
And so by the time babies are growing up a little bit, by the time they're
getting to school age, it's about 3 to 6 per 1,000 that have a permanent
hearing loss, so it is increasing.
With the early childhood outreach initiative,
which looks at hearing loss -- hearing loss that's identified, you know, from
birth to 3 years of age, we see an increase of about a doubling of this newborn
hearing screening incidence.
We can also take a look at the causes of childhood hearing loss.
In
2006, Morton published a retrospective -- Morton published a retrospective of
the causes of hearing loss, and they were seeing the incidence at birth at 1.86,
once again pretty consistent with what CDC saw in 2017 and previous years of
1.6, but about 21% of those hearing loss were the result of the GJB-2
mutation.
So almost a little over 1/5 of the babies had that particular gene
mutation that caused the hearing loss.
There were also some genetic aspects or genetic causes of hearing loss,
both syndromic, and non-syndromic, and combined about 65% or
preponderance so of congenital hearing loss is a result of genetic factors.
Congenital cytomegalovirus, CMV is also -- cytomegalovirus CMV is
another major cause, and it can be divided into CMV that's clinically apparent
in that there were other symptoms that were identified as part of congenital
CMV or clinically inapparent infection in which hearing loss was the only known
or observed or diagnosed problem as a result of the congenital CMV.
Now when we go -- Morton also looked at hearing loss and the causes of
hearing loss at 4 years of age, and they were seeing an incidence at that point
of almost 3 percent 1,000.
And combine all of the genetic factors, had gone to
about 50% because there were other reasons that hearing loss later onset had
come in and increased.
And CMV was one of those.
About 25% of the
children at age 4 were a result of congenital CMV, some of which
about -- about 10% was a later onset hearing loss.
So congenital CMV, hearing loss can occur at a later point in time, so
that's about 10% of those hearing losses.
Part of figuring out what -- what audiology is all about is understanding
an audiogram.
Now, for young children, for babies, hearing does not get
graphed on an audiogram.
degree of hearing loss is.
But it does give us an idea of what the -- the
And as a baby grows into a young child, parents
who have a child with a hearing loss, they will soon need to know about an
audiogram.
So an audiogram graphs an individual's hearing sensitivity, and it
includes both the type and the degree of hearing loss.
So across the top of the audiogram is frequency or pitch.
And it goes
from a low pitch on the left side to a high pitch on the right side.
about a piano keyboard.
So think
Left is low, right is high.
The loudness of the sound is on the up and down, and it starts with a
very soft sound at the top to a very loud sound at the bottom.
And what an
audiogram does is it -- it graphs the threshold of a person's ability to hear
sounds at different pitches or different frequencies, so a threshold is the -- the
level at which you can just barely detect that a sound has been presented.
Lept me go back here.
You'll -- let me go back here.
You'll see there are various little graphics there that graphs some
common sounds where they would fall on an audiogram.
left-hand side there you see a lawn mower.
In the lower
It's a very loud sound, and it has
a lot of low frequency, low pitched energy.
A quiet bedroom at night, higher pitched but not very loud, and then we
have some other -- other ones graphed there also.
There's also something -- a way to superimpose on the audiogram the
sounds of speech, which are composed of different frequencies at different
intensities or loudnesses.
So you can look at this and you can, hmm, it's
called a speech banana.
Okay?
It looks like a banana, and on the left side
there you see a lot of the consonant sounds.
sounds.
There are a lot of low pitched
On the right side are -- excuse me vowel sounds and some
consonants.
On the right side you see some of the higher pitched consonants like SS,
FfF.
Okay.
Those are very high pitched sounds but they're also very soft
sounds.
The red line on this audiogram here is where normal conversational
speech is.
That's the -- the intensity level of normal conversational speech.
Around 55 decibels.
The -- the intensity is measured in decibels or dB.
The
frequency is hertz, which abbreviated hZ.
Normal hearing is the pink which ranges from 0 to 15 dB across the
frequency spread.
And so those -- that's the level that you can just barely
hear those sounds and that's -- that is considered to be normal hearing.
A minimal hearing loss for children is in the range of 15 to 25 dB, and as
you can see, on the audiogram only the sounds that are below that level is
what's being per received.
So we're starting to see that some of those high
frequency sounds, those softer sounds are not perceived by the child who has
a minimal hearing loss.
So they're not hearing the FFF.
So they don't know the difference between fin and thin.
They don't
perceive that difference.
A mild hearing loss ranges from about 25 to 40 decibels, and as you
think, more of those speech sounds are being cut out.
perceived.
softer level.
They're not being
And the ones that are still audible, are coming through at a much
They're coming through more as a whisper than they are as a
normal conversational speech.
Moderate hearing loss.
Wow.
normal conversational speech level.
That's starting to encroach in the -- the
Okay?
Look how much is being cut out
of audibility there with a moderate hearing loss, and we think moderate.
That's kinds of hmm, okay.
Well, it's pretty significant when you're -- when
you're not hearing those different speech sounds.
In fact, much of the speech
is being -- is not audible.
Moderate to severe.
Most of normal conversational severe is not -- is
not per received at all, so it ranges up to -- from about 55 to 70 dB across the
speech spectrum.
But most hearing losses are not flat.
the same.
They're not across the board all
There are different configurations.
So following that red line
there of the threshold here, the red dotted line, this is -- this is a hearing loss
that goes from a mild hearing loss at the low frequencies up to a moderately
severe loss at the higher frequencies and so this is a more common type of
hearing loss.
There are different configurations of these, but -- so this person
with this type of hearing loss, you can see that there's some of the speech
sounds that are being cut out.
They're not hearing those speech sounds that
are above that dotted line, but they are hearing those that are below the
dotted line, so they'll be able to perceive those.
Okay.
Back to the -- the regular just degree of hearing loss.
Severe
hearing loss is in the 70 to 90 decibel range, and profound hearing loss is a
hearing loss that sounds have to be made 90 to 110 dB, and they not even be
perceived at that point.
Examples of different configurations of hearing loss.
The blue line is
a -- is a pretty sharply sloping hearing loss.
Pretty good hearing in the very
low frequencies but a profound hearing loss in the high frequencies, and, you
know, with amplification, the amplification is designed so that it's amplifying
only those frequencies that aren't within the realm of availability because of
the hearing loss.
Several years ago, the institute in Los Angeles put together a hearing
simulation, and the -- they took a flint stone's cartoon, and they filtered it to
mimic different types of hearing loss.
It's also available on You Tube.
Let me see if we can get this.
So what we're going to see is, we're going to go from normal hearing to
a severe hearing loss.
There's going to be a little audiogram down in the
right-hand side that's going to show how they have filtered it to mimic a
hearing loss, and you'll also see the speech banana on that, and we'll show it
twice so you can see it.
There we go.
(VIDEO)
>>SPEAKER:
One down and two to go.
>>SPEAKER:
I don't have any more money.
>>SPEAKER:
(indiscernible).
>>SPEAKER:
I won't have you talking about that way.
You got it all.
I'm not a
dummy.
(indiscernible).
>>SPEAKER:
Well it was kind of hear what will may and Betty were
saying there at the end.
You could tell from their expression that they weren't
happy and they had something to say, but if you independents the
configuration of that severe hearing loss on the right side there.
about a mild hearing loss to a severe hearing loss.
It goes from
So we'll play this one again
so you can kind of watch -- listen and then watch for that audiogram in
relationship to the banana gram.
The speech gram.
(VIDEO)
>>SPEAKER:
One down and two to go.
>>SPEAKER:
You've got it all.
>>SPEAKER:
Well ---(indiscernible).
>>MR. HOFFMAN:
Once again that's available on You Tube, if you just
Google Flintstone's demonstration.
It's a cute demonstration to be able to
use.
This is auditory transduction by Brendan.
shows how the audio system works.
A You Tube video again that
There's also another website that has
some good simulation of hearing loss, some links for simulation, and that's
Success for CAT kids with hearing loss.com.
There are a variety of different
hearing loss simulations there.
Once again that's successforhearing -- excuse
me -- successforkidswithhearingloss.com.
The take-home message is that hearing loss is described by the parts of
the ear that are affected, and it can be either temporary or permanent,
depending on the cause of it.
The audiogram is how we graph the hearing
sensitivity, and it's important to understand -- to develop an understanding of
what it means so that you can figure outer, know the audibility part, and even
mild and moderate hearing loss can significantly affect the ability to hear
speech which affects, of course, speech and language development, if not -- if
there's not any intervention.
So with that I'm going to turn it over to Terry to
talk about intervention as well as identification.
>>DR. FOUST:
Thank you, Jeff.
Just as -- just so I don't forgot, this
information has been written into a chapter in the Earl hearing detection and
intervention eBook which you can access through NCHAMs website, so you can
go back and get this same content that you're getting today at that website.
Also before I start I'd like to know a little bit about you in the audience.
How many of you are EHDI coordinator?
providers?
Great.
Audiologists, early intervention?
Okay.
Okay.
And how about
And how about parents
and families in the audience?
Okay.
Thank you.
Okay.
Adjustment as a quick reminder, Jeff already alluded to this, but
these are the JCH2 007 newborn hearing screening guidelines, and we're
operating off of that 1-3-6 model, so we want to have hearing screen by 1
month, a complete hearing evaluation, and diagnostic work-up done by 3
months and by 6 months enrolled in early intervention.
really a minimum for us.
And, again, by is
But I just wanted to -- we're going to keep these in
minds as we go forward.
I also wanted to ground us in why this is important.
This gives us a
representation of brain maturation, growth and activity from 1 month to 1
year, but this is really crucial because, you know, as these babies are growing,
and their brains are developing many little tiny synapses are electrical
connections and these are really complete by the time a baby -- by the time a
child is three years of age, and so all of this maturation is happening in this
crucial time in the first years of development so we want to get as much as
stimulation, visual, language, auditory language in as we can in order to
maximize this development.
Now, as we talk about hearing testers I want to talk about four things.
We use them for four things.
hearing loss.
So keep in mind what Jeff talked about with
We want -- the first thing we want to do is we want to determine
how significant the hearing loss is, is it mild, moderate, severe, profound?
How significant it is.
And second we want to determine what the type or the kind of hearing
loss that the child has.
So it conductive?
sound through the system?
the pathways?
A problem in the conduction of
Is it sensory in that inner ear?
Is it a combination of any of those?
Is it neural with
So we want to determine
that type of hearing loss.
And then we want to describe the configuration.
talked about that it's not a flat hearing loss usually.
shapes.
This is where Jeff
It can have different
You can have normal hearing in lows and it drops off in the highs.
You could have what we might call is a cookie bite.
down, and comes back up.
pitches and worse in others?
Where it's great, drops
So is hearing better at some frequencies and
That's what we want to know.
And we use that to make decisions and recommendations on treatment
and intervention.
Before we talk about the specific hearing tests I just want to talk about
objective versus subjective tests.
So objective tests are going to be those
where we are not going to rely on a response from the child.
Okay?
So think
of -- think of a hearing test you might have had.
You may have had
earphones placed on your ears and you raised your hand in response to a
sound.
test.
Okay?
That's a standard hearing test.
That's more of a subjective
An objective test is we're really going to look at physiological response.
We don't require the child or the person being tested to do anything.
And we
interpret those and then we look at -- and they usually look at the functional
status of the different pastors of the auditory system.
Middle ear function,
inner ear function, and function of auditory pathways.
So let's talk about these tests.
We use a lot of different tests and
instruments in audiology to assess hearing, but they'll fall into these four main
categories.
And so this is a bit of a simplification but it really will capture the
main areas that we look at.
So the first is tympanometry.
tympanogram or acoustic emittance.
middle ear function.
in.
You may have heard of it referred to as a
And really what it is is just a measure of
We put a probe into the canal.
We put some pressure
We want to move that eardrum and see how that -- that moves that whole
middle ear system, and then we look at that to see if that response fits in
several parameters if it's normal or not, and we'll talk about this a little bit
more.
But we use this test, really, to confirm or to rule out conductive or
temporary hearing loss.
The second is otoacoustic emissions or what you're going to hear
commonly as OAEs, have you all heard of that?
of inner ear function.
just talked about.
Probably.
So it's a measure
It really is generated at those inner hair cells that Jeff
Okay?
And so we measure a by-products, a little sound
that's generated there that when sound comes in, they respond, and they
actually send a small sound back out, and we're able to measure that.
an oat acoustic emission.
That's
We do that to confirm or rule out there's a sensory
problem or sensory hearing loss or component to a hearing loss.
Then the third is auditory evoked response.
Or ABR.
You've probably
heard of ABR or AABR which is second A. just stands for automated auditory
brainstem.
AABR or ABR.
Again, here now we're looking at a response as that neuro pathway goes
up through the brainstem.
And we record actual wave forms or brain waves in
response to the sound, and we use this to confirm or rule out sensory neural
hearing loss -- sensorineural hearing loss.
We're going from the outside in, right?
So you can see what's happening.
So we look at the outer ear.
to make sure it's formed and looks normal.
We want
If there's abnormalities it raises a
red flag that we could have something going on further in.
We look in the ear canal.
We want to make sure it's open and isn't
obstructed so that that sound can come in.
Then we go to tympanometry, and we try to look at the function of that
middle ear system.
And then we go to the inner ear, and make sure those little hair cells are
working right, and then we look at it from that neuro pathway up to the brain.
Okay?
And then if I said to Jeff, raise your hand, okay?
He just gave me a
response so everything went through that system, and that final step that she
just did was his brain interpreted it, heard the sound, interpreted it and
processed and it provided a response that had -- a response that had a
meaning so that goes all the way through.
Okay.
Let's talk about these quickly and just a little bit more detail.
So
tympanometry, again, is a measure of middle ear function, and we actually
measure it at the level of the eardrum.
eardrum.
The tympanic membrane or the
So like I said we put a probe in and we put pressure in and we want
to move that eardrum.
If that eardrum doesn't move we have a problem.
could be abnormally stiff due to scarring or fluid that's behind it.
It
If we put
that probe in and we can't move it but we have what we might call a large
physical volume but we measure and that space is too big it lets us know that
we might have a perforation or hole in that eardrum.
Or we get nice great normal movement, and we know that that part of
the system is functioning normally.
Okay.
Then go top otoacoustic emissions and this is a test of inner ear
functions, it's sound again rated by the hair cells and we're measure that
response by a probe put into the external ear canal.
So let's show you just a real brief intro duct -- summary of otoacoustic
emissions.
So that sound is being generated and moves that middle ear system, and
then the cochlea responds and that sound comes back out, and we measure it.
So let me -- whoops.
Let me show that to you again.
(VIDEO).
Okay?
So just watch that.
can See-The-Sound.
We've got the blue probe in the ear.
You
It goes through the middle ear, stimulates the iron ear.
That little by-products sound comes back out, and we measure it, and that's an
otoacoustic emission.
Now an ABR.
It stands, again, for Auditory Brainstem Response, and it
measures how well that sound travels along the hearing nerve and goes up
from the ear to the level of the brainstem, and we measure the quietest or the
softest level that we can get a response in that neural pathway, and so it gives
us an idea of what a child's ears can detect at those various pitches.
So an ABR is painless, and safe, but it didn't you see need to be done
when your child is quiet, and not moving because that extra movement
interferes with our ability to record those responses.
great because they're often sleeping.
So with infants it's -- it's
They're swaddled up tight.
We can do
that.
If a child is older, then often this test is done with -- under sedation or
sedation is required in order to have tests conditions quiet enough or where we
don't have the movement in order to get that.
But what we do is we put three to four really small recording disks or
electrodes at strategic places on the child's head, and behind the ears and then
we have really tiny earphones that we put right in those ear canals, and then
we put in the sounds, and we will start at a higher level, usually about a normal
conversational level, and then we drop that down, and we look at wave forms
and I'll show you in a moment.
And we look at those, and we go down to the
lowest level before we lose the wave forms.
So let me show you here.
(VIDEO)
>>DR. FOUST:
This is ABR threshold search.
All it means is we're
doing a ABR test but we are dropping down to find the lowest level that we can
still get the recognizable wave forms that we rook for.
So if you look at the top one, remember I said we usually talk about
normal conversational level, so that's about 50 decibels, and we've got really
nice wave forms right there.
Then we drop to 30 on this slide.
We drop to
20, and we drop to 10 dB, and we have normal responses here all the way
down.
Now let's look at this one.
The one on your left is, again, a normal
recording, and we've marked the recognizable wave forms that we want to
see, all the way down to 20 dB or a normal level, but then the one on your right
you can see we have a mild hearing loss threshold showing.
here.
We've got 60 dB.
So we start up
We drop to 40, and then to 30, and we just barely
have a response there at 30, and we have no response at 20.
Okay?
We just
kind of have unmatching wave forms that -- that are not giving us a response.
Now we go to what Jeff did.
me a behavioral response.
When I told Jeff to raise his hand we gave
So it went all the way through and Jeff gave me
the appropriate response that I gave him in that instruction.
That's a
behavioral response.
In kids and young children we can't test that way.
when you hear the sound.
Raise your hand
It's going to be a tiny little sound.
always work, but we have other methods that we use.
That doesn't
So we'll use visual
reinforcement audiometry or VRA is what we call it but what it means is we
give something visually interesting as a reinforcement to a response to sound.
So I might have a child sitting on their mom's lap, and I might have
speakers that are located on each side.
and a dark box.
So in order -- and they lighted toy
And in order for the child to see that, they have to make a
complete head turn.
So I'll give a loud sound, and I will pair rot with that toy
lighting up or flashing, and they'll look.
And very quickly this child will learn
when that sound comes on there's that reinforcement, and we can test them
that way.
We can also with older kids, we use what we call conditioned play
audiometry.
a puzzle.
That's where we introduce a fun game or task.
They hold a puzzle to their ear, listen, listen, and the sound comes
in, and they get to put the puzzle piece in.
bucket.
We might have
Give me five or put a toy in a
We make it fun and interesting.
Kids with -- depending on their developmental level and hearing levels
and things, this works really well.
Okay.
So those are the tests, and just bear with me.
the outside in.
We worked from
We go to where the sound is interpreted with meaning.
We
have a behavioral response, and then we use that information now to make
recommendations on treatment and intervention.
So the first thing we want
to look at is is there anything medically that we can do?
ear disease for example, weed want to treat that.
that's deemed appropriate.
If it's chronic middle
It might be antibiotics if
Or it could be tubes -- pressure equalization
tubes, PE tubes that are inserted to aerate that space and get it to function
normally.
We also work to maximize residual hearing or to stimulate hearing, and
I'll talk about the difference there in just a moment.
So hearing aids, are they appropriate?
And can they benefit?
And
then there's a real skill set to fitting hearing aids for the pediatric population.
Cochlear implants and FM systems.
And then we move to early intervention for overall development which
includes communication modalities, emotional, social, cognitive, overall
development, and then as audiologists we want to be -- we want to be working
with all of those teams that provide that so that we can help maximize that
auditory environment, use our skills to ensure that that amplification or
the -- is the best that we can do for a cochlear implants are working.
And also
what we can do to help maximize different environments.
And so let me play this one for you.
This -- actually she introduces
herself, but I'll play it and then we'll talk about it.
Whoops.
I lost my mouse.
I apologize.
(VIDEO)(indiscernible)
>>SPEAKER:
That was crista 10 years old.
she's amplified with hearing aids.
Okay.
Severe hearing loss, and
Now this -- let's see -- is that playing?
Again, early intervention.
(VIDEO)
(indiscernible).
>>DR. FOUST:
So those little guys were identified early.
Early
intervention, and you can see what their language skills were for age, which
was great.
Now, so let's look at this -- at these two little guys who were cochlear
implant recipients.
(VIDEO)
(indiscernible).
[laughter]
>>DR. FOUST:
We're going to talk about cochlear implants quickly in a
minute but I think these two described it better than I can.
So hearing aids.
I think the main message here is that they can be
fitted as -- as young as a month of age.
We fit them very early.
I have
babies who go home from the hospitals with hearing aids.
This just gives you a view of some various hearing aids, but really in
pediatrics we do need to focus on several things.
We -- because those little
ears grow so fast we often tell our parents we may need to resize the part that
fits into the ear every time they change shoe sizes for example, and we look at
flexibility.
You know, as -- as a parent or family or whoever purchases
hearing aids, we don't want to have to -- if hearing were to change buy another
pair next wear.
So we look for flexibility in fitting changes that can occur, for
example.
Hearing aids really are amplifiers so we have the sound that comes in.
It's captured by the microphone.
It's amplified.
That amplifier is powered by
a battery, and then it sends it out through a speaker louder and delivered into
the ear canal.
So what it delivering to the ear canal, that sound has to go
through the system just like that.
So the system is being driven with louder sound but we're not making
any changes to the system, if that makes sense.
Now, when we go to cochlear implant, that's a little bit different.
cochlear implant is not amplifying sound.
ear that the inner ear isn't doing.
The
It's replacing a function in the inner
Does that make sense?
The device is surgically placed in the iron ear, and it stimulates it to
cause hearing.
We're not amplifying but we're stimulating that to cause
hearing.
So there are four parts.
There are -- there's an external microphone
which is the part that p hooks over the ear just like it looks like kind of like a
hearing aid, and has a microphone and captures that external sound.
Then
the part that you saw that young man put up on his head, that's the sound
processor, so the mic captures it, the processor processes the sound, and
sends it transdermally or through the skin to a magnet that's attached to the
bone of the skull.
So it goes right through the skin that way.
On the other side, then, which if you look at number 3 on here, that's on
the other side, there's an internal receiver stimulator, so it takes that sound
transdermally into the system, and then it fires that electrode which you can
see the straight line coming down, and it comes and is inserted into the snail
shaped portion of the inner ear.
If we unrolled that snail-shaped portion, it's -- it has a really specific
organization for frequency.
Okay?
So you -- you would have your high
frequencies and you unroll it you go to your lows.
Okay?
So that's why, you
know, for example, on do we want to determine if someone is a good candidate
for it, we want to make sure that we can get good insertion through the length
of that cochlea so that we can try and stimulate as many frequencies and
pitches as we can.
Does that make sense to everybody?
There are criteria for cochlear implant candidacy.
The two main criteria
right now are demonstrated lack of benefit from traditional amplification.
we need to know that hearing aids are really not that helpful.
The age is 12
months for the FDA clearance right now, and it's kind of specific.
children two years of age and older, severe to profound.
So
It's for
If you're a year of
age, then it is profound only.
But there are exceptions and some kids are implanted younger.
The last thing in this category is FM systems and that stands for
frequency modulated.
It's really like a radio signal where a teacher will wear
a mic, the sound is amplified -- or sent directly to the child's hearing aid, and
it helps eliminate the background noise so it helps improve the signal to noise
ratio but the background noise cuts that out, lets them get the primary signal,
and makes that more clear.
Okay.
With maximizing the auditory environment, we want to make
sure that a child's amplification is working or their cochlear implant.
train in the use of the device.
We can
We want to help with classroom placement so
we can maximize seating and visual benefits.
background noise, and strategies like that.
We want to help them reduce
Now, what does that mean?
Just real quickly let's talk about speech sounds.
If we took -- let's do -- just follow me.
So let's do M.
Okay.
Do M -- and then Ah, and EEE.
you can see what we're doing is going from lower to higher pitched sound.
Ah, EEE, SS, SH.
So
M,
We went from low pitch to high pitch, and also what
happened we lost the voicing when we got to the SS, and SH.
Right?
So let's take a pair of sounds like B, and P, Ba, Ba, and now Pa, Pa.
the only different -- visually it looks the same, B and P, right?
difference is the voicing.
Okay?
Now
But the
So a child with a high frequency hearing
loss is going to have more difficulty with high frequency sounds, even though
they look the same on the lips.
The difference is the voicing.
So the B might
be easier, right, if they have a high frequency loss or a better hearing in the
lows.
Does that make sense?
So there's a lot of things that we want to do to help.
So let me quickly give you an example before we wrap up.
time -- so distance.
Distance is really important factor.
So every
So let's say my child
is four feet away from me.
or a loud whisper level.
Four feet.
And I'm talking at about a 30 decibel
They're at four feet.
Now the way acoustics works is every time I half the distance or I
decrease the distance by half, the sound grows or gets louder by 6 decibels.
Okay?
So let's do that.
So at four feet, and it's 30 dB so I'm kind of talking
in a loud whisper.
And then I bring him into 2 feet, and then a child within a foot and I'm at
42 decibels so see how I've made it louder by bringing him close?
So we tell our parents with their infants that we want them close.
6 to
12 inches from the mic on their hearing aid for example.
Same thing is a classroom.
Seat them up close because we're working
with the physical way that sounds work, and they just get louder as you get
closer.
I could do the same thing with the mic.
bring it closer it finally kicks in.
I'm talking at loud, and as I
So we work with strategies like that.
The listening bubble is just a distance.
Again, it's the same thing.
What you want to do is actually test the kid with your voice.
Find out within 6
feet, is that best for their hearing or do I need to bring them closer?
We call
it the listening bubble.
Okay.
So this is actually the baby that I read, the last wave forms on,
on an ABR, and this baby is severe to profoundly hearing impaired, and she's
7 weeks old, and as I was coming here today I thought this is the first time that
I'll give this talk or talk to a group with this perspective because this baby's my
granddaughter, and so that young mom is my daughter.
And so
I'm -- it's -- it's just a different perspective as I talk to you today.
And I really
hope that if I could be of any hope to you as you work to help these children
meet their maximum potential, that you'll reach out, and I thank you for your
attendance today, and, again, all of this information is summarized in that
chapter in the EHDI book so you can use it as a resource, and we thank you for
your time.
(APPLAUSE).
(END OF MEETING)