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Flashcards in Immittance Deck (20)
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0
Q

Admittance

A

Ease with which energy flows through a system

1
Q

Immittance

A

How readily a system can be set into vibration.

-incorp recipie ok concepts of admittance and impedance

2
Q

Impedance

A

Extent to which the system resists the flow of energy

3
Q

3 measurements collected in immittance

A
  1. Static acoustic compliance (tympanonmetey)
  2. Tympanometry
  3. Acoustic reflex
4
Q

Tympanometry

A

ME admittance measure

-goal is to define the point and magnitude if greatest compliance of TM

5
Q

Tympanogram

A

Admittance - y axis

Air pressure in ear canal - x axis

6
Q

Admittance measures

A
  1. static acoustic admittance
  2. Equivalent ear-canal volume
  3. Tympanic peak pressure
  4. Shape
7
Q

Static acoustic admittance

A

Peak y
Measures mobility of TM
Peak max compliance - where pressure on both sides is equal
Total A = y(outer ear) + y(middle ear)
Redu SAA - fluid filled mE or ossicles not vib
Inc SAA- dis artic of ossicles or abnormal elasticity of TM

8
Q

ECV

A

Vol of air in front of probe (medial) and lateral to tM

Abnormal ECV - proliferation in TM; tube in TM (little to no compliance); small (wax impact ion)

9
Q

Tympanometric Peak Pressure (TPP)

A

Measure (indirect air pressure in ME

10
Q

Shape of tympanogram

A
Type A - normal
Type As - shallow peak 
Type Ad- deep peak 
Type B - flat 
Type c - negative peak
11
Q

Acoustic reflex testing

A

Results from contraction of ME muscles (stapedius) in response to intense sounds
-stiffens ME - decreases SAA

12
Q

Two pathways for acoustic reflex

A
  1. Ipsilateral : signal and decrease in compliance - same ear
  2. Contra lateral : dec in TM compliance in ear opposite to ear that receives signal
13
Q

Acoustic reflex threshold (ART)

A

Lowest intensity level at which there is a measure able admittance change in ME system as a function of intense sound stimulation

14
Q

Four outcomes of ART

A
  1. Present at norm SL (~85dBSL)
  2. Absent at limit of system (~110 dBHL)
  3. Present but at low SL (100 dBSL)
15
Q

Otoacoustic emissions (OAE)

A

Generated from normal cochlea in the outer hair cells.

Function: sharpen or amplify the cochlea traveling wave.

16
Q

Two classes of OAEs

A
  1. Spontaneous: occur w/o acoustic stimulation. Occurs in 50%
  2. Evoked: occur with stimulation
17
Q

Evoked OAEs - two types

A
  1. Transient evoked too acoustic emissions (TOEAEs). Obtained by presenting a brief stimulus - broadband
  2. Distortion product emissions (DPOAEs). Result from interaction of two simultaneous pure tones
18
Q

Evoked oAEs - when present and absent?

A

Present - when hearing t/holds are normal

-absent in frequency regions where there is cochlear hearing loss of 40-50dB HL or more

19
Q

Auditory Evoked Potentials (AEP) also ABR (auditory brain stem response)

A

Measurement if time that elapses from acoustic stimulus presented and time it takes for brain to generate electrical activity in response to stimulus
Short middle and long latencies