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Exam 3

Terms in this set (88)

Why do we complete speech audiometry?
To evaluate how someone is hearing in their everyday life
The main pro for using MLV is that
it may make the patient more comfortable
Downside of MLV is that
individuals speak differently and it can be hard to keep your voice steady
The main pro for using recorded materials is
It's the exact same way each time that its presented with recorded material
The downside to using recorded materials is
slow and awkward response time, can be confusing
Speech Detection Threshold
the lowest level that speech can be detected 50% of the time; use spondee words to test but can use anything that is speech; use MLV to test
Speech Recognition Threshold
softest level that stimuli can be repeated or understood 50% of the time; can point at pictures if they are unable to produce speech, use spondee words
Word Recognition Testing
evaluates speech at suprathreshold levels (one level above their threshold) usually 40 Db SL; use the NU6 or the W22
Pure tone test validity is comparing
SRT and PTA, good (+/-6), fair (7-12), or no agreement (12+)
dB SL=
dB HL of stimulus - dB HL of pt threshold
Describe the three performance-intensity functions that might be seen for word recognition and which populations typically display each.
As sl gets higher performance gets better (line one conductive or normal hearing)

Plateaus; may not be 100%, no matter how much louder they stay at their best performance, sensorineural

Retro cochlear hl, sound louder until they reach best which isn't 100% and then they roll over and get worse when the sound gets louder
What is tympanometry testing
The function of the middle ear is being tested
How is tympanometry tested
Is tested with a tympanometer which changes pressure in the ear canal and measures admittance
What do tympanometry tests tell us
Results tell us how well the middle ear is functioning at different pressures
Admittance
the ease at which energy flows thru the acoustic system
Impedance
the opposite of admittance; examines the acoustic resistance of the middle ear
Immitance
general term that refers to both admittance and impedance, general for how energy flows into the system
Type A tympanogram
Normal ear
Type B tympanogram
fluid or perforation
Type C tympanogram
Middle ear pressure is negative
Ear Canal Volume is
length and size of the ear canal down to the ear drum; large ECV is when there is a hole in the eardrum (type B)
In what situation do we measure the highest admittance of the middle ear?
When the middle ear pressure equals the atmospheric pressure
What feature of tympanometry allows us to determine if a patient has a perforation in their tympanic membrane?
Tympanogram type B - large ear canal volume
What is the acoustic reflex?
What happens to the middle ear when a loud sound is played
How is the acoustic reflex measured?
Playing tone in the ear and measuring it on either the same or opposite side
Why is the acoustic reflex considered a bilateral response?
Reflexes happen in both ears simultaneously
Auditory Brainstem Response
stimulus evokes change in electrical activity; is used to test for auditory nerve/brainstem lesions or getting thresholds in babies or hard to test pts
Test length for ABR is
45 mins for adults and 3 hours for babies
Response from brainstem in ABR is
small
Longest ABR wave is
fifth
How do we use ABR
Electrode measures the electrical activity in the brainstem -- Stimulus played; present more than 1 freq at a time but to find threshold have to use pure tones -- Play the sound 1000 times and average the results
What does the averager do during ABR
It picks up changes in brainstem, averages info over time ending w the response for sound in the BS
Transducers role in ABR
insert ear phone, can use different ways to get bone or air conduction
How do we measure ABR
Measuring the response coming from the brainstem--Measures from the auditory nerve to the inferior colliculus
Interneural latency difference/delay
Compare how long it takes for wave five in one ear and the other, what time does each happen and they should be almost identical, if they aren't then sent to doctor
Interwave interval
waves 1,3 or 5, looking at time difference between two, how long from wave one to wave five or wave one to wave three
Absolute
time from 0 when sound is played, how much time is there until we get out waves 1,3, and 5; amount of time for wave 1 or 5 to have a normal reading
If numbers are too long to get to the waves (latency in ABR) there may be an issue with
their nerve
Latency
Looking at ABR; it is the info about the amount of time the response took
Amplitude
The size of the wave; ratio size of waves to each other
Why do we use wave V to determine hearing thresholds using the ABR?
It's the largest and the clearest and the most stable
What do we need in order to get a normal ABR?
Synchronous firing of neurons — hair cells sent to auditory nerve cells 1&2 causing action potential
Neurons have to fire at the same time to get recordable response
Many neurons firing
If we dont get normal ABR, what effect will this have on the ABR?
ears will have different responses
What are otoacoustic emissions
Come from outer hair cells
When we damage outer hair cells we don't get OAEs
If damage to auditory nerve we still get otoacoustic emissions
OEA measurement is same range that outer hair cells respond to
Ohcs can lengthen and shorten on their own
OAEs are from movement of ohc's
who discovered OAEs
David Kemp
What is the cochlear amplifier
When outer hair cells in the cochlea amplify low intensity sounds that are coming in
How does the cochlear amplifier work
They have the motor protein prestin that allows them to get longer and shorter — When they lengthen and shorten it effects how far the basilar membrane moves which makes sound louder in the cochlea
How do we know that OAEs come from the outer hair cells?
Thru testing; if OHC's damaged there are no OAE's
When prestin is absent there are ___ OAEs
no
The levels of OAEs are _________ to those of OHCs
similar
Even if the auditory nerve is cut in half or damaged, what happens to OAE
we still get OAEs
SOAEs
spontaneous; interesting but not helpful, sounds that are always there no sounds are played, only 30% of normal ears have these
TEOAEs
transient evoked; play brief complex sound into the ear and get a reflection of the complex sound back out of the cochlea
DPOAEs
distortion product; playing 2 into the ear and the cochlea generates a 3rd at a diff freq than the two we played (generated inside the cochlea) this is the sound we actually measure
The different types of OAEs are helpful in clinic because
pts who have hearing loss don't have them, if OAE is there then we say cochlea is good and functioning normally if no OAE its not and there is likely hearing loss
TEOAEs frequency ranges that are most sensitive to separating normal hearing from hearing loss
TEOAE's are from 1000-3000 hz
DPOAEs frequency ranges that are most sensitive to separating normal hearing from hearing loss
2000 to 6000 hz
What will happen to OAEs if someone has middle ear issues
OAE's generated inside cochlea but the microphone is located in the air canal so we play sound and it goes thru middle ear into cochlea, OAE vibrates footplate, ossicles, and eardrum creating sound in ear canal, middle ear cannot transmit sound well into or out of the cochlea if the middle ear is damages, not be they aren't there bec the middle ear cannot get it into the cochlea to be sent back
Why will OAEs be impacted by middle ear issues
Middle ear can't get OAE back out into the ear canal if there is an ear infection or damage in the ear
Why is universal newborn hearing screening important?
3-6 in every 1000 babies born w HL every year
What cant the newborn hearing screening tell us
they cannot tell us what they cannot hear or are having trouble with - cant predict future hearing loss
undetected HL leads to
poor academic abilities and speech delays
0-3 months is the critical period for
newborn hearing
What is the goal of early hearing detection and intervention
Identify HL early
Provide intervention
Improve speech and lang outcomes
How is the newborn hearing screening completed?
w/in 24 hours of birth, separate kids into likely normal or likely HL, done thru ABR or OAE but ABR preferred
What are the possible results of the newborn hearing screening?
Pass or refer
What are the steps in the newborn hearing screening and early intervention process
Initial screening, re-screening, diagnostic testing, intervention
Whats the 1-3-6 rule?
Screen all babies by 1 month
Diagnose all babies' w hearing loss by 3 mos
Provide intervention by 6 mos for those with hearing loss
What are the advantages to newborn hearing screening?
ideal conditions, efficient testing, guaranteed testing, follow up more likely to occur if nurse makes apt while parents still in hospital
What are the disadvantages to newborn hearing screening?
high noise level, vernix or fluid in ears, preemies (get tested before discharge not after birth), hospital stays are short, HL can have delayed onset
Behavioral observation audiometry
looks for natural response to sound (in babies), no reinforcement, dependent on tester observation (tester bias), not reliable
Visual reinforcement audiometry
train child to look when sound is played (6 mos - 3 yrs), reinforce behavior w visual stimulus, vary sounds to find their threshold
Conditioned play audiometry
train child to play a game (2.5 - 5 yrs), reinforce child with verbal praise, vary intensity of sound to find threshold
SDT testing in children
calling name, "bah bah bah"
SRT testing in children
picture spondee, pointing to body parts, following directions
word recognition testing in children
PBK-50, WIPI
SDT is lowest when they can detect sound is present ___%of the time and SRT is when they can understand it ___%
50% and 50%
SDT is any type of speech— it results in
dB HL
SRT are usually
spondee words, repeat them softer until they cannot repeat it correctly (understand it)
Pure tone test validity is comparing SRT and PTA
good (+/-6), fair (7-12), or no agreement (12+)
NU6 and W22 are for
word recognition in adults, not much difference between the two
Typically for word rec we want to be at
40dBSL base it on their SRT, it needs to be in dBHL
Know HINT and QuickSIN are speech in
noise tests; how well they do in background noise
Facial nerve only sends info
down
If muscle doesn't contract imittiance
doesn't change
What are you looking for when measuring AR
change in immittance
Possible AR outcomes
present at normal and absent
admittance is always highest when pressure on both sides is
equal (ear canal and middle ear)
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