Lecture 3 Flashcards

1
Q

What number on a tymp shows it is type Ad?

A

Compliance/static admittance

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2
Q

A ____ volume size is a pretty good indicator of normal volume

A

2.0

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3
Q

Why is a 3.0 volume and type A tymp normal?

A

Because the peak shows that the TM is working fine (a hole would show a type b tymp)

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4
Q

What classification of tymps is most commonly used?

A

Jerger classification system

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5
Q

The normal frequency for a tympanogram is ____Hz and we measure the ____ component

A

226Hz, Y

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6
Q

Y = ____

A

Total admittance

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7
Q

But, you can run tymps up to ____Hz on some commercial machines

A

2000

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8
Q

The higher the frequency, ther harder it is to maintain ____

A

Constant SPL

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9
Q

MFC measures Y, but can extract ____ and ____ components from that measure

A

B, G

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10
Q

When do you use MFC tymps?

A
  • unusual Y tymps (the conventional tympanogram)
  • neonates
  • severe mixed losses when its difficult to mask B/C results
  • to estimate ME resonance frequency
  • an indicator of cochlear involvement
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11
Q

What are some unusual Y tymps that may result in needing MFC tymps?

A
  • type Ad (hyper-compliant tymps)
  • normal tymps with A/B gaps
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12
Q

What do MFC tymps usually distinguish between?

A
  • ossicular discontinuity
  • monomeric/atrophic TMs (ME is still working okay, just a flaccid TM)
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13
Q

What are monomeric/atrophic TMs?

A
  • The TMs consist of 3 layers (outer epithelial, medial mucosal, and inner fibrous)
  • If you get a lot of ear tubes, the inner layer may not heal (the TM becomes more flaccid), but overall, the TM is not working good
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14
Q

What does this tympanogram indicate?

A
  • regular Y tymp (type b)
  • Large volume
  • Either a perforation or an open tube
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15
Q

What does this tympanogram indicate?

A
  • type As (flaccid component)
  • no perforation, but still abnormal (static admittance is 4.4ml)
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16
Q

What is better for picking up cracks in ossicules? CT or MFC tymps?

A

Sometimes CT scans wont pick up a crack in the ossicles (abormal HF tymps pick up ossicular discontinuity more than CT)

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17
Q

What does the C mean in MFC tymps?

A
  • multi-component
  • various mechano-acoustic elements can be separated out from each other and recorded (susceptance and conductance)
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18
Q

What admittance element is associated with stiffness/springiness?

A

Compliant susceptance (Bc)

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19
Q

What admittance element is associated with mass?

A

Mass susceptance (Bm)

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20
Q

What admittance element is associated with friction?

A

Conductance (G)

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21
Q

Stiffness/springiness, mass, and friction = ____

A

Total admittance (Ya)

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22
Q

Why are mass and stiffness/springiness both under susceptance (B)?

A
  • Mass and stiffness are both under B because the mass effects are depending on stiffness, and stiffness is dependent on how much mass there it
  • When you change the mass, the stiffness effects change
  • When you change the stiffness, the mass effects change
  • With B, you can see which effect is dominant over the other
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23
Q

Conductance (G), is a function of ____ friction

A

Inner ear fluid

24
Q

What is meniere’s disease?

A

Inner ear fluid and pressure problem (causes LF fluctuating HL, tinnitus, vertigo) – an inner ear fluid disorder

25
Q

What is the difference in MFC tymps of someone with and without meniere’s?

A

The Meniere’s group had significantly wider G tymps

26
Q

Conductance (B) is ____ and ____

A

springiness/stiffness, mass

27
Q

Susceptance (G) is ____

A

Friction

28
Q

What are you looking for in B/G tymps?

A

How many peaks there are

29
Q

Explain this MFC tymp

A

This is a 3 B 1 G tymp

30
Q

Why does the B tymp notch down?

A
  • Why is the B tymp notching? That is where the peak of the tymp would be on a regular Y tymp (this is a normal Y tymp = type A)
  • It is notching down because mass and stiffness are balancing out
31
Q

What is the instruments concern with regular tympanometry?

A
  • Total admittance determined by/proportional to the voltage necessary to maintain probe tone SPL
  • i.e. a function of magnitude
32
Q

What is the instruments concern with MFC tymps?

A

Concerned about the timing of the ME response that is then measured in the ear canal

33
Q

Phase differences are dependent on what is going on in the ____

A

Middle ear

34
Q

Explain the timing patterns of mass and stiffness

A
  • Stiffness is is ¼ cycle ahead of the dricing force
  • Mass is a ¼ cycle behind the driving force
  • Mass and stiffness are in total opposition of eachother
  • Friction is in sync with the driving force
35
Q

When are mass and stiffness not dominating one over the other?

A

at 0 value

36
Q

Explain the Argand Plane

A
  • It is at a 90 degree angle because stiffness it is a quarter cycle ahead of the driving force and mass is a quarter cycle behind the driving force
  • Mass and stiffness are in total opposition of eachother
37
Q

How does the MFC device determine B and G?

A
  • Collects a measure of admittance Y
  • And uses the phase difference between the speaker and microphone as an angle value to determine B and G
38
Q

Go over Argand Plane ppt slides (43-51)

A
39
Q

What is resonance?

A
  • When the elements of elastic/springiness and mass are balanced and one element is not more dominant than the other
40
Q

When does resonance happen?

A
  • When the phase (angle) of B = 0
  • When there is no timing/phase differences between the speaker and mic
  • When the peak of the B tymp deflects down just to the baseline of the B tympanogram
41
Q

Is Fo of this tymp above or below 678Hz?

A
  • Peak of the B tymp falls right on baseline = 0
  • Resonant frequency is 678Hz
42
Q

B tymp should never have more than ____ peaks

A

5

43
Q

G tymps should never have more than ____ peaks

A

3

44
Q

What is the normal range for normal resonance?

A

650-1200Hz

45
Q

What happens to the B value as you increase frequency?

A

As you increase frequency, the B value gets less and less and will become negative (as the mass effects start to take over)

46
Q

What are the 2 things to interpret MFC tymps?

A
  1. Reference the tympanograms to normal middle ear resonance
  2. B/G pattern approach
47
Q

What determines the Fo?

A

The mid peak of the B tymp

48
Q

What is the width of the B tymp?

A

Between the distal peak

49
Q

What is an abnormal MFC tymp?

A
  • More than 5 peaks in the B tymp
  • More than 3 peaks in the G tymp
  • Width
    • More than 75 daPa for 3B tymp
    • More than 100 daPa for 5B tymp
    • More than 60 daPa for a 3Y tymp
50
Q

What is this ME resonance?

A

Greater than 678Hz and less than 1000Hz

51
Q

What is this ME resonance?

A
  • Have gone beyond resonance (negative value)
  • Resonant frequency is below 226Hz
  • Not normal resonance frequency
52
Q

there is a normal pattern progression for MFC tympanograms that depends on the ____ used for the tymp

A

Frequency

53
Q

What is the Vanhuyse labelling system?

A

Vanhuyse system is classification based on the number of peaks
1B1G
3B1G
3B3G
5B3G

54
Q

The appropriate tympanogram pattern depends on the frequency of the ____ tone used.

A

probe

55
Q

Go through case studies on ppt (72-108)

A