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This was a patient who was identified as a child

0:04

with down syndrome who had hearing loss.

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So in looking at a down syndrome patient,

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of course we're going to look for both the conductive

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as well as sensory neural causes of hearing loss. And

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in the conductive standpoint, as I mentioned,

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the most common finding is chronic otitis media.

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As we look in the external auditory canal in this

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child with down syndrome, we see this unusual structure

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that appears to be attached to the middle ear tympanic

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membrane. This is a Myringotomy tube.

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A Myringotomy tube is what is sometimes inserted

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through the tympanic membrane in children who have

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chronic otitis media to help them drain the fluid from

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the middle ear cavity into the

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external auditory canal.

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So this is a child who has, at baseline, problems,

0:57

obviously with chronic otitis media.

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And as we look at the caliber of the external

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auditory canal, we see that it's normal.

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So there is no atresia or stenosis,

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which is one of the findings in down syndrome.

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We look at the ossicles next.

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So the ossicles look normal with the cochlea...

1:15

I'm sorry,

1:15

with the malleus and the incus and the parallel lines

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of the neck of the malleus and

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long process of the incus.

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And we come to the incudostapedial joint with

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a normal appearance to the stapes.

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So we've cleared the extraordinary canal,

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except for the myringotomy tube.

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The middle ear cavity, at least on this side,

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is clear. And now we go to the inner ear structures.

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We'll start with the most common and look

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for that dilated endolymphatic sac,

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which is normal in this individual.

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You can see the endolymphatic sac or vestibular

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aqueduct is actually smaller in size than the

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semicircular canal, just adjacent to it.

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So that's not the issue.

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We look into the vestibule and the cochlea.

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We see immediately that there is a problem here.

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So normally what you would see is a piece of bone

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right here, which would separate the vestibule from

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the lateral semicircular canal. Instead,

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we have lost this bone island centrally and that is

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one of the most characteristic features

2:19

of down syndrome inner ear anomalies.

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The second of the common features is

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cochlear aperture stenosis. Now,

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there's two different things that we can see

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with cochlear aperture stenosis,

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we can see narrowing of the aperture,

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but the other thing that we can see is the bony

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obstruction of the cochlear aperture.

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In this case, this is too much bone right here.

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This is the normal modiolus.

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But at the cochlear aperture, there's too much bone

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right there and this is cochlear aperture stenosis

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on the basis of bony stenosis. As we look

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at the semicircular canals,

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we see that the posterior and the superior

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semicircular canals are normal.

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And notice that the caliber of the limbs are

3:09

symmetrical. Here we have the arcuate artery here.

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And as we look at the cochlea,

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we have the normal basal turn,

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we have the middle turn and we have the apical turn.

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We just have this bony stenosis of the...

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at the aperture. Let's look at the contralateral side.

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So here we are with the left ear and we see, all right,

3:34

well, this looks pretty good from the standpoint

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of the external auditory canal.

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There is some soft tissue in the middle ear cavity and

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probably the remnant of a myringotomy tube going

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through the tympanic membrane, also on the left side.

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The middle ear ossicles look okay.

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Here's their stapes.

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Here's our incudostapedial joint.

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There's a little bit of soft tissue between the neck

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of the malleus and the long process of the incus,

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which is likely residual from chronic otitis media.

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Let me magnify that.

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So normally, you'll see the bone here and then the bone

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here without this intermediate

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intervening soft tissue.

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This is likely remnants from chronic otitis media.

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But let's focus again on the inner ear structures.

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So in this example,

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we again have a large vestibule and

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a hypoplastic bone island here.

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So I would normally expect the width of the vestibule

4:36

to maybe be here and then the lateral

4:39

semicircular canals to be like this.

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And instead,

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we have this somewhat dilated vestibule on the left

4:45

side and a small bone island right here, separating

4:49

the limbs of the lateral semicircular canal.

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But more importantly,

4:54

what we see is this very narrow cochlear aperture.

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And we have to look on multiple slices,

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but this is a very narrow cochlear aperture in a

5:05

patient who has cochlear aperture stenosis

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due to narrowing on the left,

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but due to bony overgrowth on the right hand side.

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This never really widens out right through here,

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and it's always quite narrow to get into the cochlea.

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And here we have this sort of blunted and

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foreshortened, and a little bit dilated lateral

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semicircular canal with a small central bone island.

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And these are the findings that we can see in the

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inner ear of patients with down syndrome.