Tympanometry Flashcards

(48 cards)

1
Q

What is tympanometry

A

a test of integrity of the TM and middle ear function

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2
Q

what are the three main measures of tympanometry?

A
  • tympanogram
  • acoustic reflexes
  • other: reflex delay, ET function
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3
Q

What is immitance?

A

a measure of how readily a system can be set into motion by a driving force

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4
Q

What is admittance/ compliance?

A

the ease with which energy will flow through a vibrating system

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5
Q

What is impedance?

A

the extent to which a system resists the flow of energy though it

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6
Q

What three factors determine the impedance of system? which one is the most important?

A
  • stiffness **most important
  • resistance
  • mass
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7
Q

If the ear has high compliance this means that there is _______ sound bouncing back to the ear

A

minimal

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8
Q

T or F the ear drum vibrates most efficiently when pressure is equal on both sides

A

true

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9
Q

As pressure displaces the TM from rest what three things happen?

A
  • decrease in vibratory efficiency
  • decrease in energy flow
  • increase in sound bouncing back
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10
Q

What does a tympanogram measure

A

it measures changes in compliance as a function of air pressure changes in the ear canal

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11
Q

On a tympanogram, as compliance increases, sound ______

A

decreases

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12
Q

Describe a Type A tympanogram

A

point of greatest compliance is at 0 daPa (-100 to 100 daPa) and compliance is normal

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13
Q

Describe a Type As tympanogram

A

pressure is normal, but compliance is low so the peak is not as big

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14
Q

Describe a Type AD tympanogram

A

pressure is normal, but compliance is high so the peak is larger

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15
Q

Who has a Type A tympanogram

A
  • people with normal hearing

- people with sensorineural hearing loss

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16
Q

Describe a Type B tympanogram

A

there is no point of greatest compliance, it is a flat tympanogram

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17
Q

Who has a Type B tympanogram

A
  • People with conductive hearing loss
  • People with advanced otosclerosis
  • People with fluid in their middle ear
  • People with perforated ear drum or PE tubes
  • Could also be caused from a blocked probe
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18
Q

Describe a Type C tympanogram

A

the point of maximum compliance occurs when negative pressure is in the ear canal, so pressure in the middle ear must be negative (less than -100 daPa)

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19
Q

We don’t normally see hearing loss until the negative middle ear pressure reaches _____ daPa

A

-150

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20
Q

Who would have a Type C tympanogram?

A
  • People with ET dysfunction
  • If you have a cold
  • If you just got off of an airplane
  • Pressure from large adenoids or tonsils
21
Q

Kids with negative middle ear pressure will often return with ______ in middle ear space due to effusion

22
Q

What are the two important things to look at when reading a tympanogram?

A
  • pressure at the peak

- height of the peak (compliance)

23
Q

What is the range of normal compliance values?

A

.30 - 1.70 cm3

24
Q

If you have a compliance value smaller than the normal range, it means that the ear has ________ than normal mobility

25
If you have a compliance value larger than the normal range, it means that the ear has ________ than normal mobility
greater
26
The first step in a tympanogram is figuring out the compliance of the outer ear. How do we do this?
- Immobilize the eardrum with positive pressure (+200 daPa) - There is a large amount of sound returned to the probe, this helps us determine the volume of the outer ear in cm3 which represents the compliance of the outer ear
27
The second step in a tympanogram is figuring out the compliance of the outer ear and middle ear together. How do we do this?
- Decrease the pressure in the EAM until the TM reaches maximum compliance - Increased mobility allows more energy to be admitted by middle ear, there is decreased sound coming back to the probe
28
What is involved in the third step of a tympanogram?
-We take the measurement of the outer ear + the middle ear and we subtract out the outer ear to find the compliance of the middle ear only
29
What is typical ear canal volume?
between 0.6 - 2.0cm3 with ear difference less than or equal to 2cm
30
With a Type B temp and a normal ECV the lesion is likely where?
middle ear space
31
With a Type B temp and a high ECV the lesion is likely where?
tympanic membrane (perforation)
32
With a Type B temp and a low ECV the lesion is likely where?
- outer ear canal - clogged probe - probe against wall
33
Predict the tymp type for someone with microtia
Type A
34
Predict the tymp type for someone with a middle ear tumour
Type B
35
Predict the tymp type for someone with an incompletely formed cochlea
Type A - there is no impairment in the outer or middle ear
36
Predict the tymp type for someone with a marble stuck in the EAM
Type B
37
Predict the tymp type for someone with inflamed tonsils and adenoids
Type C
38
Predict the tymp type for someone with a large TM perforation
Type B
39
Predict the tymp type for someone with noise-induced hearing loss
Type A (noise-induced HL is typically sensorineural)
40
What is the acoustic reflex?
a stiffening of the middle ear in response to intense sounds
41
The acoustic reflex is frequency specific, to what frequencies?
500-4000Hz
42
The acoustic reflect may be absent if there is damage in the auditory pathway below the _______
superior olive
43
What is an ipsilateral acoustic reflex?
present a signal to one ear and detect a decrease in TM compliance (increase in stiffness and sound bouncing of TM) in that ear
44
What is a contralateral acoustic reflex?
present a signal to one ear and detect a decrease in TM | compliance in the opposite ear
45
T or F the acoustic reflex typically occurs unilaterally
F - it occurs bilaterally
46
What level of dB HL elicits the acoustic reflex?
less than or equal to 100 dB HL
47
People with what type of temps demonstrate a acoustic reflex?
- measured with Type A - never with type B - seldom with type c
48
What are the 3 small tubes within the metal probe on the tympanometer?
1) air pump 2) tone generator 3) mic