Midterm 2 Flashcards
what are we now learning about high frequency audiometry?
We learning that high frequency audiometry is more of a sensitive measure for detecting damage to the auditory system. (however there is still a lot of research being done in this area) However it has been used of ototoxic monitoring for a long time.
What is a common use of high frequency audiometry?
monitoring for ototoxicity
or
ototoxicity monitoring
What transducer type must be used for high frequency audiometry?
circumaural headphones
Does the transducer type matter for high frequency audiometry?
Yes, circumaural headphones
What is the IA value for circumaural headphones?
Same as Supras
40
Briefly describe the AAA protocol for OME screening.
o 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)
Define the term acoustic immittance
How well energy flows though a system
Define the term acoustic impedance
Opposition to the flow of energy
Define the term acoustic admittance
Ease with which energy flows through the system
What are the three components of the probe for tympanometry?
The probe its self has 3 components
1. Tone that is played when tymp is ran
2. Microphones picks up sound in my space while running it.
3. Air pressure- changes air pressure
Probe looks like what
Probe is the one with the three tubes it is used for
Tymps
Air pressure generator
Microphones
Tone generator
Stim looks like what
Acoustic reflexs - black tube only generates just a tone. also known as (stim)= sound
Describe the instrumentation for immittance measures.
Sound goes in the ear, changes the pressure and measure the sound in the ear as the pressure changes by the microphone.
X= pressure
Y= admittance
How is a tympanogram derived?
Derived: It is changing pressure, and it is plotting admittance.
- Increase impedance
- Decrease admittance
- Measure sound transmission at each pressure point and compare to norms
What is the premise underlying tympanometry?
Premise: The admittance is greatest when the ear canal pressure matches the middle ear pressure.
what is the adult norm for static admittance
Peak Compensated Static Admittance (Ytm)
0.3 – 1.7 mL
what is the adult norm for Equivalent Ear Canal Volume
Equivalent Ear Canal Volume
0.9 – 2.0 ml
what is the adult norm for Tympanogram Width (TW)
Tympanogram Width (TW)
50 – 115 daPa
what is the adult norm for Tympanometric Peak pressure
Tympanometric Peak pressure:
-100 to +50 daPa
Name the values for a normal tymp
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
What is Tympanic peak pressure
- point where middle ear system is operating most efficiently
- Peak approximates but does not measure middle ear pressure
What is Static Admittance
Static Admittance
- tympanogram peak height
- Static admittance - Ytm
- Frequently referred to as compliance or peak compliance
- Measures stiffness or “floppiness” of the ossicular chain/middle ear system
What is Ear Canal Volume
Ear Canal Volume
– literally tells you the “volume” size of the ear canal
- Ear canal volume provides useful information about the status of the TM such as….
o Intact TM
o Patent PE tubes
- Ear canal volume provides information about the ear canal such as…
o Estimate blockage
o Surgical ear
Why do we report numbers over 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.
Describe Type A
A
○. normal range
○ Peak is in the box
Describe Type As
A(s)
○ very shallow peak
○ Peak is below the box
○ Associated with otosclerosis
○ Can also occur with otitis media
Describe Type Ad
A(d)
○ very high (deep) peaks
○ Peak is above the box
○ Found in otherwise normal ears that had scarred or flaccid eardrums
○ Also found in cases of ossicular interruptions it above 1.7 it’s a d or dd
Describe Type B
● Essentially flat across the pressure range
● Characteristic of patients with middle ear fluid and cholesteatoma
● Could also be caused by eardrum perforations or impacted cerumen (or other obstructions) in the ear canal
Describe 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
Name the Tymp type
Type A
Name the Tymp type
Type C
Name the Tymp type
Type Ad
Name the Tymp type
Type As
Name the Tymp type
Type B
Does it matter how you measure a reflex? If yes explain.
Yes, You have to run a tymp first to pressurize the ear canal because you want to measure a reflex at the patients peak pressure because admittance is greatest at peak pressure.
what measure from the tympanogram changes when an acoustic reflex is present?
Admittance is what changes with a present acoustic reflex. The admittance decreases during the reflex because the reflex causes the ossicular chain to stiffen causing a decrease.
What is the minimum amount of change required to consider if a reflex is present?
.02
admittance, performed at the peak pressure (amount of reflex)
What are the five criteria for a reflex to be considered valid?
- Lowest level that elicits “criterion change”
- Time locked to stimulus onset
- Replicable
- Growth- stronger response present 5dB above/ Reflex is stronger the further you go above threwshsold.
- A decrease of admittance.
What is considered a normal ASR (Acoustic Stapedial Reflex) ?
70-90 dB SL
An acoustic reflex would be expected with hearing loss up to what level (cochlear)?
60 dB HL
identify reflex patterns associated with normal hearing
Acoustic reflex norms are considered in dB SL
70 – 90 dB SL is considered “typical”
If clinic uses norms from a study, must use same procedures as study
what is considered “reduced” reflex
If the reflex less then < 70 dB SL it is considered “reduced”
What is considered “elevated” reflex
If the reflex is greater then > 90 dB SL it is considered “elevated”
What is considered “NR”
If the reflex is NR it is considered “absent”
NR = you tested but there was no reflex at the maximum level of testing
Calculating dB SL
Reflex threshold in dB HL – air conduction threshold for the stimulus ear.
ANSD:
bilateral, you would see this with a sensorineural HL, retrocochlear and you would have absent reflexes at a level where you would expect a reflex. It is retrocochlear
SSCD
is when you have a conductive loss but all your reflexes are normal and your admittance is normal as well. It a vestibular system but its changing your sensitivity of air conduction and bone conduction. It makes your air conduction sensituvity worse and bone better. Normal tymp and normal reflex.
ascending =
Stim ear
cochlear, retro, middle hl - stimulus ear will be abnormal
descending =
Probe
every time the probe ear is the right ear, the reflexes are absent
crossover =
brainstem
Reflex patterns for Sensorineural Hearing loss
Ascending pathway is affected with sensorineural hearing loss. For both cochlear and retrocochlear
Descending pathway is not affected with sensorineural hearing loss
Different pattern for cochlear vs. retrocochlear
dB SL of the reflex when the affected ear is the stimulus ear
Cochlear : < 70 dB SL
Retrocochlear: > 90 dB SL or ABS/NR
Reflex patterns for Cochlear
● Sensorineural hearing loss
● Reflexes are affected when the affected ear is the stimulus ear
● Smaller < 70 dB SL
● “stimulus effect”
● “stim effect”
● “sound effect”
● Generally, you should expect a reflex for hearing losses up to ~ 60 dB with cochlear hearing loss
● If AC thresholds are larger > 60 dB, absent reflexes are not diagnostic. (above 60)
Name the reflex
Cochlear
Reflex Patterns Vestibular Schwannoma
● Sensorineural hearing loss (or NH)
● Reflexes are affected when the affected ear is the stimulus ear
● Larger/above >90 dB SL (usually absent)
● “stimulus effect”
● Likely absent unless hearing thresholds are very low
● If AC thresholds are > 60 dB, absent reflexes are not diagnostic
○ Remember there are sometimes conditions for interpreting test results?
Name the reflex
Vestibular Schwannoma
Reflex patterns for Conductive HL
● Conductive pathology affects the descending pathway
● Reflex (typically) can not be measured in ear with middle ear condition
● Reflex will be absent when the affected ear is the probe ear.
○ “probe effect”
○ The contralateral reflex for the affected side will be 70-90 dB above the hearing thresholds at that ear
■ will be near the limits of the equipment or absent
Name the reflex
Conductive HL
Name the reflex
Brainstem Pathology
Reflex patterns for Brainstem Pathology
● Contralateral reflexes will be absent with ipsilateral reflexes present
● “crossover pattern”
● Cannot differentiate type of brainstem pathology on reflexes alone
What type of pathology is suggested here based on AC thresholds and reflexes?
Facial Nerve - affecting the probe ear and there is no HL
What type of pathology is suggested here based on air conduction thresholds and acoustic reflexes?
Cochlear - SL is lower than 70 indicative of cochlear HL of the RE stim
What type of pathology is suggested here based on air conduction thresholds and acoustic reflexes?
Cochlear
What type of pathology is suggested here based on air conduction thresholds and acoustic reflexes?
Retrocochlear - NR on the left ear as stim and it is in the same ear suggestive of retro and because HL is 60 or better, they should have reflexes
What type of pathology is suggested here based on air conduction thresholds and acoustic reflexes?
Conductive - probe side is on the left and with probe no response + HL = conductive
What type of pathology is suggested here based on air conduction thresholds and acoustic reflexes?
Brain stem. - it is the contras that are affected and no HL
Fill in table
How many people total are positive for the disease (have the disease?
100 - total that tested positive and total that had it but tested negative (30+70)
How many people total are negative for the disease (do not have the disease)?
525 500+25=525
How would you calculate sensitivity? (How good is our test at identifying those correctly who have the disease)
30/100 (30+70=100)
Number of true positives / total number who have it
How would you calculate specificity? (how good our test is at identifying those who do not have the disease)
500/525 (500+25=525)
Number of true negatives / total number who do not have it
Is standard low frequency tympanometry good at differentiating between otosclerosis and a normal middle ear?
No, it is not very good. You can have a normal tymp with otosclerosis.
It is good at determining middle ear fluid.
What is a primary factor that influences sensitivity and specificity for a specific test?
Is where your cut off is what you consider a pass or fail.
How you set your screening criteria. (if you have it more sensitive or not.)
Briefly describe the AAA protocol for OME screening. You do not have to memorize the entire thing because clearly you could look it up if needed.
o 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)
What is a common use of high frequency audiometry?
Ototoxicity monitoring
What is high frequency audiometry good for?
We learning that high frequency audiometry is more of a sensitive measure for detecting damage to the auditory system. (however there is still a lot of research being done in this area) However it has been used of ototoxic monitoring for a long time.
what is a more sensitive measure for detecting damage to the auditory system.
We learning that high frequency audiometry is more of a sensitive measure for detecting damage to the auditory system. (however there is still a lot of research being done in this area) However it has been used of ototoxic monitoring for a long time.
What transducer type must be used for high frequency audiometry?
circumaural headphones
What is the IA value for circumaural headphones?
Same as Supras- 40
An abnormal static admittance volume reading suggests a disorder where?
TM and/or ossicular chain
An abnormal peak pressure reading suggests a disorder where?
ET, Eustachian Tube (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?
TM (perforation)
Which measure is outside of normal limits for one or both ears?
Static admittance (abnormally low) - As right ear
Normal Peak Compensated Static Admittance (Ytm) 0.3 – 1.7 mL
Unimpaired auditory system
Hearing thresholds are WNL AU
All reflexes present at 70-90 dB SL
