Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Diagnostic Audiology > Lecture 2 > Flashcards

Lecture 2 Flashcards

1
Q

What is admittance measuring?

A

the total absorbency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What two components make up admittance?

A

Conductance (G)
Susceptance (B)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Conductance = ____

A

Friction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Susceptance = ____

A

Stiffness and mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

daPa = ____

A

Pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

mmho = ____

A

Admittance (Y)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How did the oldest tympanometer work?

A
  • There was no built-in pump (instead they would manipulate the pressure in the room)
  • A thermometer would measure the pressure in the room
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

mmho converted to to ml is called ____

A

Equivalent volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What do you see with a TM perf on a tymp?

A

A large volume because you are measuring the volume of the OE and ME

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do you check tubes?

A

Do tymps. A normal tymp means the tube is blocked and a flat tymp means the tube is open and working correctly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Explain sound in a small, hard walled cavity

A
  • A small cavity has low admittance (this means sound will be louder in a small space)
  • The sound will want to be louder, but has to be turned down to maintain constant SPL
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Explain sound in a large, hard walled cavity

A
  • A large cavity has high admittance (this means more sound is being absorbed, it is quieter)
  • The sound will want to be quieter, so it has to be turned up to maintain constant SPL
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why did Otto Metz choose a LF probe tone?

A

Because HF tones were often distorted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Only a ____ tone can be used to estimate the ear canal volume.

A

low frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why can a HF tone not estimate the ear canal volume?

A
  • High frequency sound is processed by mass characteristics of the ME (letting the sound through)
  • At low frequencies, the ME is dominated by stiffness (impeding low frequencies)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

So why is a 226Hz probe tone used?

A

Because at 226Hz, the mmho value and the equivalent volume value align.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the difference between using a 226Hz probe tone vs. a 1000Hz probe tone?

A
  • At 226Hz, any mmho value can be converted into Vea
  • At 100Hz, the numbers do not align
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Acoustic admittance of a 1 cubic cm/1 ml cavity is equal to 1 mmho at ____

A

226 Hz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What pressure and Hz is the estimate of the EAC taken at?

A

226Hz at +200daPa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why does the probe tone have to be LF?

A

because HF tones have high admittance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How do we know this tymp is measured at 226Hz?

A

Because Vea is measured (which is equal to mmho at 226Hz)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does it mean if Vea is not present on the tymp?

A

We dont know (all we know is that it isnt 226Hz because if it was, Vea would be present)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is equal at 226Hz?

A

mmho and Vea (ml is a measure of volume which is equal to mmho at 226Hz)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the immittance test battery?

A
  1. Tympanometry
  2. MFC tympanometry (multi frequency multi component)
  3. Acoustic reflex testing
    • Acoustic reflex decay testing
  4. Admittance over time (AOT)
    • AOT for patulous eustachian tube (PET)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the acoustic immittance instrument for tympanometry?

A

Tympanometer

26
Q

What does a tympanometer measure?

A

Measured change in admittance (Y) in response to pressure changes applied to the ear canal space

27
Q

How is the tympanometer working?

A
  • The speaker puts out a probe tone
  • The microphone monitors it to maintain a constant SPL
  • The pump pumps air in and out of the OE
  • If we pump a bunch of air into the ME, the TM will balloon inward and the stiffness increases
  • Slowly the air is removed from the OE, and the TM becomes less stiff (sound is quieter; going through ME)
28
Q

Whatever is being absorbed by the ME is being ____

A

replaced

29
Q

What does the peak of the tymp mean?

A

This is where the TM can vibrate most freely

30
Q

What is happening when there is an increase of pressure into the OE?

A

Increase in pressure causes increasing stiffness and the ME can’t absorb sound. This causes the sound to maintain in the OE (the sound is louder and to maintain SPL, voltage goes down)

31
Q

What are the 6 steps to measure tympanometry?

A
  1. place test probe in EAC and achieve airtight seal
  2. activate pump so pressure reaches +200daPa
  3. collect estimate of canal volume
  4. start recording
  5. adjust pump so that pressure steadily decreases into the negative pressure range
  6. continue until at least -200 or until peak is achieved (-300 to -400daPa limit)
32
Q

What is an MFC tymp used for?

A

Helpful for determining ossicular disorders
B tymps = dark
G tymps = faded

33
Q

What are the 7 steps to measure MFC tympanometry?

A
  1. determine probe tone frequency
  2. usual protocol is B/G tympanometry
  3. place test probe in ear canal and achieve airtight seal
  4. activate pump so that pressure reached +200daPa
  5. start recording
  6. adjust pump so that pressure steadily decreases into the negative pressure range
  7. continue until at least -300 or until peak(s) is/are achieved
34
Q

What is acoustic reflex testing measuring?

A

Change in acoustic admittance (Y) in response to an activating acoustic stimulus (stim tone)

35
Q

What are we NOT doing in AR testing?

A

There is no pressure change

36
Q

When testing AR, we are measuring a very ____ admittance change of about ____.

A

small, 0.02mmho

37
Q

Explain this AR test

A
  • probe tone: 226Hz (ml value)
  • stim tone: 1000Hz
  • the probe and stim tone are both being presented in the right ear (I = ipsi)
38
Q

What are the 6 steps of testing AR?

A
  1. complete tympanogram
  2. set pressure to the point of the highest admittance value (peak) of the tymp
  3. AR option will measure very small admittance changes
  4. 0.02ml/mmho will be a positive response
  5. activate stim tone, either ipsi or contra
  6. measure admittance changes in response to stim tone
39
Q

Where does the TM move the easiest?

A

At the peak of the tymp (most compliant)

40
Q

AR shows a ____ in admittance

A

decrease (the stapedius muscle stiffens the ME which causes admittance to go down)

41
Q

Explain this AR test

A
  • probe tone: 226Hz (ml)
  • stim tone: 1000Hz
  • probe is in the left and stim is in the right (contra)
42
Q

What is another name for the admittance over time (AOT) test?

A

Ambient pressure tympanometry

43
Q

What is AOT measuring?

A

A measure of the ME compliance/admittance over an extended period of time

44
Q

What is NOT happening in AOT measuring?

A

There is no change of pressure or stim tones, only the probe tone is presented.

45
Q

What is the frequency of the probe tone for AOT?

A

687Hz (more sensitive to events that are happening in the ME)

46
Q

What are the 4 steps of an AOT test?

A
  1. set AR instrument for reflex decay or other long time window setting
  2. turn stim down or off; set to contra but do not put contra stim-phone in ear if possible
  3. run test presentation
  4. a stable ear should show a flat tracing across the whole time
47
Q

What is this AOT showing?

A

Pulsatile tinnitus (if it was normal, the line would be flat, but it is synchronis to the individuals pulse)

48
Q

What is this AOT showing?

A

PET (can see this when the person stops breathing)

49
Q

Why can cerumen cause a flat tymp?

A

Wax is blocking the ME; just another solid wall (no matter the pressure changes, the admittance won’t change)

50
Q

Why is daPa used for tymps?

A

It is the unit of pressure (pumping air in and out)

51
Q

Why is there a peak on the tymp?

A
  • The ME admittance is changing to maintain constant SPL
  • The peak refers to where the pressure in the OE and ME are equivalent
52
Q

If the peak is negative, what does this suggest?

A

It would mean there is negative pressure in the ME (because the peak is where the OE and ME are equal)

53
Q

What is missing on this tymp?

A

The air in between the ME and the probe (in the space of the EAC)

54
Q

Does this show total ME function?

A

No. We are mostly measuring the TM and the air trapped in there, not the ossicles/past the TM. This is a test of ME immittance not total ME function.

55
Q

Explain compensated vs. uncompensated tymps

A

Uncompensated
- shows the volume of the OE and ME

Compensated
- subtracts the OE and just shows the volume of the ME (static admittance)

56
Q

Where is the volume estimate of an EAC taken from on this tymp?

A

Take the volume estimate at 226Hz at +200daPa = 2.5ml

57
Q

What are the main components of a tympanogram?

A
  1. static admittance/compliance (peak TM)
    • the height of the tymp (ME admittance only; compensated tymp)
  2. ear canal volume (equivalent estimat)
  3. peak pressure
  4. morphology (shape, width, gradient)
  5. compensated vs. uncompensated
58
Q

Explain static admittance

A

Right tymp
- the lower the height of the tymp, the stiffer the TM is
Left tymp
- the taller the height of the tymp, the more compliant (hypercompliant in this example)

59
Q

What is the range of compliance?

A

0.2-2.0

60
Q

What does it mean if you get a 3.0ml volume and a normal tymp?

A

If its a big guy, you wouldn’t expect there to be a hole even though it’s outside of the normal range, because the shape is type A and you wouldn’t see a pressure change with a perforation.

Diagnostic Audiology (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions