Exam 2 Flashcards by Libby Sarra

What type of testing does immittance testing encompass?

tymps, Tympanometry, Ear canal volume measurement
Acoustic reflex testing (Acoustic reflex threshold
Acoustic reflex decay) Tests of Eustachian tube function

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What structures are assessed using immittance measures?

tymp middle ear
reflexes - effect on middle ear, auditory nerve, cochlea, b.s., facial nerve

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What are the components of an immittance meter?

probe signal (tone)
air pressure
microphone

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How is immittance testing conducted?

based on changing the pressure in the ear canal and measuring sound levels in the ear canal

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Define the term acoustic immittance

Flow of sound energy

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acoustic immitance evaluates

Tympanic membrane
Middle ear space, including ossicles
Middle ear reflex
Involves middle ear
Cochlea
Auditory nerve
Auditory brainstem pathways
Facial nerve

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Describe the instrumentation for immittance measures. What are the three components of the probe for tympanometry?

probe itself has 3 components
tone that is played when tymp is ran
microphone picks up sound in me space while running it
air pressure - changes air pressure

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how does immitance testing work

sound goes into the ear, changes the pressure and measure the sound in the ear as the pressure changes by the microphone= tymp

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what is on the y axis for immitance

admittancew

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what is on the x axis for immitance

time? or Pressure?

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How is a tympanogram derived? What is the premise underlying tympanometry? (Hint: it has to do with the admittance of the middle ear and pressure.)

Changing the air pressure in the ear canal in either direction cause TM and ossicular chain to stiffen
Increase impedance
Decrease admittance
Measure sound transmission at each pressure point and compare to norms

Peak admittance occurs when pressure in the ear canal is roughly equivalent to pressure in the middle ear

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adult norms for static admittance, tympanometric peak pressure, ear canal volume, and tympanogram width

Peak Compensated Static Admittance (Ytm) 0.3 – 1.7 mL
Tympanogram Width (TW) 50 – 115 daPa
Equivalent Ear Canal Volume 0.9 – 2.0 ml
Tympanometric Peak pressure: -100 to +50 daPa

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what does ear canal volume measure

Ear canal volume provides useful information about the status of the TM
Intact TM
Patent PE tubes

Ear canal volume provides information about the ear canal
Estimate blockage
Surgical ear

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what is static admittance on a tymp

tymp peak height

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what does static admittance measure

Static admittance - Ytm
Frequently referred to as compliance or peak compliance

Measures stiffness or “floppiness” of the ossicular chain/middle ear system

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what is tymp peak pressure

point where middle ear system is operating most efficiently

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what does tymp peak pressure measure

Peak approximates but does not measure middle ear pressure

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what is a type a

normal
peak in the box

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what is As

shallow peak
associated with otosclerosis and can with otitis media
peak below the box

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what is Ad

high peak
above the box
found in ossicular interruptions or scarred/flaccid eardrums

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what is type b

flat across all pressure ranges
middle ear fluid and cholesteatoma or eardrum perfs and impacted cerumen

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what is type c

Negative pressure peaks beyond -100 daPa
Indicating negative ear pressure
Peak is to the left of the box
Associated with eustachian tube disorders
Also found in cases of middle ear fluid

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Which muscle is involved in the middle ear muscle reflex in humans?

stapedius

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What are the two clinical uses of the MEMR/ASR?

cross check
determine site of lesion

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What measurement (from the tympanogram) changes in the ASR?

admittance, performed at the peak pressure

What is the minimum amount of change in this measurement that would be considered a reflex?

.02

What are the five criteria for a reflex?

Lowest level that elicits “criterion change” 2. Time locked to stimulus onset 3. Replicable 4. Growth- stronger response present 5dB above/ Reflex is stronger the further you go above threshold. 5. A decrease of admittance.

what measure from the tympanogram changes when an acoustic reflex is present

admittance

What is the minimum amount of change required to consider a reflex is present?

.02

What is considered a normal ASR?

70-90 dB SL?

An acoustic reflex would be expected with hearing loss up to what level (cochlear)?

60 dB HL?

what is acoustic immittance

flow of sound energy

what is acoustic impedance

opposition to energy flow

what is acoustic admittance

ease of energy flow

Describe the instrumentation for immittance measures. What are the three components of the probe for tympanometry?

probe itself has 3 components tone that is played when tymp is ran microphone picks up sound in me space while running it air pressure - changes air pressure

what is on the axis of tymps

x is pressure and y is admittance

How is a tympanogram derived? What is the premise underlying tympanometry?

How is it measured? What is the machine doing? Changing the pressure and plotting admittance as the pressure changes The admittance is greatest when the ear canal pressure roughly matches the middle ear pressure

what are the norms for static admittance

.3-1.7 mL

what are the norms for peak pressure

-100 to +50 daPawh

what are the norms for ear canal volume

.9-2.0 mL

what are the norms for tymp width

50-115 daPa

An abnormal static admittance volume reading suggests a disorder where?

™ and/or ossicular chain

An abnormal peak pressure reading suggests a disorder where?

ET (not functioning)

An abnormally low ear canal volume reading suggests a disorder where?

Ear canal (blockage)

An abnormally high ear canal volume reading suggests a disorder where?

Which measure is outside of normal limits for one or both ears?

approximates but does not measure middle ear pressure

peak pressure

point where middle ear system is operating most efficiently

peak pressure

requently referred to as compliance or peak compliance

static admittance

Measures stiffness or “floppiness” of the ossicular chain/middle ear system

static admittance

provides useful information about the status of the TM intact tm patent pe tubes

ecv

provides information about the ear canal Estimate blockage Surgical ear

ecv

why reporting numbers is preferred to describing the shape

We use the numbers to compare to the norms and it is more precise and gives a clearer picture than just giving A or B etc.

normal range tymp

shallow peak

very high peaks

essentially flat

negative pressure peaks beyond -100

Know what measure from the tympanogram changes when an acoustic reflex is present. What is the minimum amount of change required to consider a reflex is present?

Does it matter how you measure the reflex? Do tymp so we measure at the PT’s peak pressure because admittance is greatest here We are monitoring admittance and if it decreases during a reflex (causes chain to stiffen) we want .02 change 105 is the highest we go (it is ok to mark reflex here without showing no growth as long as it meets other criteria and is replicable)

What are the five criteria for a reflex to be considered valid?

What is considered a normal ASR?

70-90 dB SL

An acoustic reflex would be expected with hearing loss up to what level (cochlear)?

60 dB HL

How would you calculate specificity?

Number of true negatives / total number who do not have it

How would you calculate sensitivity?

Number of true positives / total number who have it

Is standard low frequency tympanometry good at differentiating between otosclerosis and a normal middle ear?

Low frequency audiometry is what we do, standard tymp No it is not good at it, you can have normal tymp with otosclerosis Good for middle ear fluid

What is a primary factor that influences sensitivity and specificity for a specific test?

You can make it more sensitive which lessens specificity and vice versa How you set the screening criteria We want high sensitivity that causes those who have good hearing to still pass but making sure we catch all that do have HL Depends what we are testing for which we want

Briefly describe the AAA protocol for OME screening.

Calibrate equipment daily o Screen with OAE or tones before doing tymps o Refer if TW and/or static admittance suggest flat tymp (you could look up the specifics as needed) o NPP greater than -200 (do not refer on this criterion alone)

Is high frequency audiometry more sensitive measure for detecting damage to the auditory system.

maybe, still researching

high frequency test frequencies

10, 11.2, 12.5, 14, 16, and 20 kHz but will vary by audiometer

What is a common use of high frequency audiometry?

monitoring for ototoxicity - medication they take that damages the auditory system

What transducer type must be used for high frequency audiometry?

Circumaural headphones - AC transducer only IA is similar to that of supra-aurals

associated with otosclerosis can occur with otitis media

Found in otherwise normal ears that had scarred or flaccid eardrums Also found in cases of ossicular interruptions

Characteristic of patients with middle ear fluid and cholesteatoma Could also be caused by eardrum perforations or impacted cerumen

Associated with eustachian tube disorders Also found in cases of middle ear fluid

If the reflex < 70 dB SL it is considered

reduced”

If the reflex is > 90 dB SL it is considered

“elevated”

If the reflex is NR it is considered

“absent”

ASR is a ______ response

bilateral

SNHL affects stim or probe?

stim

ascending pathway

stim ear

descending

probe ear

How are reflexes used clinically?

Differentiate cochlear from retrocochlear Confirm/identify middle ear involvement Identify facial nerve pathology Identify SSCD Identify functional/nonorganic hearing loss

unimpaired AS ASR

Hearing thresholds are WNL AU All reflexes present at 70-90 dB SL

cochlear pathway

ascending

retrocochlear pathway

ascending

is descending pathway affected with SNHL

Cochlear :

Cochlear : < 70 dB SL in stim ear

Retrocochlear:

> 90 dB SL or ABS/NR stim ear

Generally, you should expect a reflex for hearing losses up to ____ with cochlear hearing loss If AC thresholds are > 60 dB, absent reflexes are not diagnostic

~ 60 dB

If AC thresholds are > 60 dB, absent reflexes are

not diagnostic

Conductive pathology affects

descending pathway

Reflex (typically) can not be measured in ear with middle ear condition

conductive

Reflex will be absent when the affected ear is the probe ear. “probe effect”

conductive

The contralateral reflex for the affected side will be 70-90 dB above the hearing thresholds at that ear

conductive

Exam 2 Flashcards

(95 cards)