1
Q
what are OAEs
A
Low-level sounds emitted by the cochlea, either spontaneously or as an echo or other sound evoked by an auditory stimulus, related to the function of the outer hair cells of the cochlea
2
Q
are OAE’s a test of hearing?
A
Not a test of hearing; only tells the function of the cochlea and OHCs (no neural or cortical)
3
Q
what are the benefits of OAEs
A
objective, noninvasive, do not require behavioral responses (like TEOAEs)
4
Q
what are the 4 regions of the auditory system that play a role in oaes
A
Outer ear
Middle ear
Inner ear
Efferent system
5
Q
what is inward propagation (oaes)
A
travels from outer ear in eac to the middle ear where the ossicles move the fluid in the cochlea by the stapes footplate in the oval window
the fluid movement causes the basilar membrane to shear the stereocilia atop of the outer hair cells
outer hair cell stereocilia shearing causes ion exchange to occur (K+ rushes in causing it to elongate and shrink)
OAEs are created from this dancing of OHC and is sent back out through the oval window pushing the stapes footplate through the ossicles to the ME to the TM and out into the ear canal to be picked up by the mic and transmitted to the computer for analysis
6
Q
what is outward propagation? (oaes)
A
Impedance mismatch - decreases up to 15dB
Backward transmission is less efficient; oval window is smaller surface area sending signal to larger surface TM via ossicular chain, resulting in lost intensity during the transmission
7
Q
how does the middle ear play a role in outward propagation (oaes)
A
reverse sound propagation through me is not very efficient
the systems that act as the impedance matchers hinder for the reversal transmission
8
Q
what is the spiked heel effect (oaes)
A
Sound moves from the big area of the eardrum (TM) to the small oval window, which increases pressure
9
Q
what are the possible oae outcomes
A
- Amplitude is normal (relative to an appropriate normative region),
- Amplitude is abnormal (OAE is present but below normal limits), or
- There is no evidence of reliable OAE activity above an acceptably low noise floor (Absent)
10
Q
what is the difference between a screening and diagnostic oae
A
Screening: fast, portable, not as expensive, results are pass/fail, less frequencies assessed (usually HFs), 3/4 to pass, you use fewer frequencies with the screening, you get an automatic result, and you went to screen from highs to Lows
Completed to distinguish those who do not have significant auditory dysfunction from those who need further evaluation
Diagnostic: detailed analysis of cochlear function, including more frequencies, takes longer, A component of a comprehensive test battery, Requires interpretation from audiologist
11
Q
what are the medical red flags contraindicating oae recordings
A
Active ear canal drainage
Foreign body in the ear canal
Active bleeding in the ear canal
12
Q
what types of hearing loss can we miss with oaes
A
Ansd
Mild hearing losses
Atypical configurations (especially LF losses or only HF losses)
Delayed onset or progressive losses
Neural and/or genetic IHC loss only (normal OHC) which are rare
13
Q
what is the role of the efferent auditory system
A
- Protects from acoustic trauma
- Helps hear in noise
- Plays a role in attention & auditory training
13
Q
what will oae results look like for a patient with an open vs closed PE tube
A
Patent/open PE tube
Will be present
Can interpret that the PE tube is working, infection has drained out and cochlea is functioning well behind that
Closed PE tube
Not present or present
Cannot determine of ME is the cause of findings
Must retest after ME resolves
14
Q
what are ototoxic drugs that affect OAEs
A
aminoglycosides
chemo drugs
quinine
loop diuretics
salicylates
15
Q
what TESTS does ototoxic monitoring consist of
A
Conventional audiogram
DPOAEs (up to 10,000 Hz)
HF audiometry
16
Q
what are TEOAEs
A
sounds emitted by the cochlea in response to a brief, transient stimulus (usually a click )
17
Q
how do TEOAEs work
A
- Click presented into the ear through earphone
- If the outer hair cells are functioning normally, they generate a measurable sound in response
- This response is picked up by a sensitive microphone placed in the ear canal
18
Q
what are TEOAEs used for?
A
NBHS
Quick check of cochlear health for noise or ototoxic exposure
19
Q
what is the PL for TEOAEs
A
74-83 dB SPL
20
Q
what do you watch while running a TEOAE
A
the stimulus, in this image A is good
21
Q
what does reproducibilty look like in a TEOAE
A
- a and b waveforms should approximate 100%
- two waves with overlap almost completely
- Takes half the sound measured and puts in bin a and takes the other half and puts in bin b and if there are emissions and overlay each other, you have good reproducibility
22
Q
what do we look for for a “present” TEOAE
A
Absolute emission > -10 dB SPL
SNR (relative value) > 3-5 dB (varies)
Reproducibility of 70% or greater
23
Q
how do we counsel with a TEOAE
A
“The results of your test of assessing the inner ear didn’t give us a response which is consistent with a hearing loss of mild or more and is not a test of hearing so we need to do more testing to see if there is hearing loss”
23
if a TEOAE is considered "present" what is our interpretation of the results
- Normal or near normal cochlear function
- Hearing better or equal to approximately 25-30 dB at frequencies where emissions are present
24
label this image of a TEOAE
1. Stimulus
2. The spectral waveform (frequency response) of the click (a flat spectrum is desirable)
3. Stimulus intensity level and stability
4. Noise
Want this as low as possible
5. TEOAE response spectrum
6. Noise and TEOAE response spectrum measured
7. reproducibility
25
interpret this result
Stimulus is not good
Reproducibility is not good
No responses
26
interpret this result
Left is present and more reproducible than the right
Noise floor is high in right ear
27
interpret this result
Less sweeps and poor reproducibility in the right which could be the reason for less emissions
28
interpret this result
Low reproducibility
Test run was good but still no response
29
interpret this result
Stimulus good
Reproducibility and emissions poor
30
what does this mean?
the probe is out of the ear or not in correctly
31
what is a DPOAE
Measure’s the ear’s ability to produce sounds in response to 2 simultaneous tones
32
how does a DPOAE work
- two pure tones (f1 and f2) are played into the ear
- If the outer hair cells are functioning normally, the cochlea generates a third sound, a distortion product, is measured at 2f1 – f2
- This sound can be detected using a sensitive microphone in the ear canal
33
what are DPOAEs used for
NBHS, Monitoring ototoxicity, & Diagnosing SNHL
34
what are the benefits of DPOAEs
DP thresholds can be interpreted to the audiogram
Gorgagrag - DP gram version with normative values from the 5th percentile to the 95th percentile and is used to indicate if hearing is normal, abnormal or borderline
35
what are the PL for DPOAEs
L1 & L2 (55/65 dB SPL - 10 dB separation)
36
what does a present DPOAE look like
- absolute emission (DP) >/= -10 dB SPL. aka absolute dp value or dp level
- SNR (relative value ) (DP-NF) >/= 6dB (3-5 dB for some) reflects avg noise around DP frequency
- Replicable
- Plot on dp-gram/gorgagram
37
when will a DPOAE be absent
When HL >40 dB HL
*without a gorgagram or when L1 & L2 are low and unequal, hearing
HEARING OF
38
how do you calculate F2 & DP
f1 = 1000 Hz
f2= 1220 Hz
2f1-f2 = 2000-1220
DP = 780 Hz
Output measured in the ear canal which was not present in the input signal
May be plotted at f2 (1220)
39
what is each of these colors
39
what do these results indicate
present OAEs basd on the f2 frequency
40
what do these results indicate
OAEs are present at 5kHz and the rest are not
41
what do these results indicate
OAEs are present except 3 kHz
42
what mediates suppression OAEs
Suppression is mediated by medial olivcochlear efferents
43
what are suppression OAEs characterized by
Decrease in amplitude and peak phase of emission
44
what will you see if a suppression OAE is normal
Decrease in amplitude in the presence of noise about 5dB
45
what will you see in an abnormal suppression oae
Lack of suppression or decrease in amplitude (ANSD or non-functioning efferent system)
45
what is a pressurized oae
OAE measurements taken while controlling or adjusting the static air pressure in the ear canal
Negative middle ear pressure can affect OAE measurements
46
what is the usefulness of a pressurized OAE
Middle ear conditions can suppress or distort OAEs and by adjusting the ear canal pressure to match the middle ear pressure (during tymps) you equalize the pressure, allowing for a more optimal testing of the cochlear function
47
what is the protocol for a pressurized OAE
Perform a tymp to adjust the ear canal pressure
Record OAEs
48
why are LF the most affected with significant ME pressure (oae)
Retracted tm and negative pressure in the middle ear results in stiffness in the system, which causes the ME to not vibrate the way it normally does. Stiffness results in a high-pass filter, which eliminates the LFs
49
why are all frequencies affeted with fluid or fixed ossicles
Causes the eardrum to not move at all, resulting in a mass-dominated system causing absent OAEs and all frequencies to be equally affected
50
describe the active and passive processes related to OAEs
Active
OHCs
Responsible for low-level threshold sensitivity
Passive
IHCs
Stimulated above 70 dB
51
What is the primary function of the medial olivocochlear system (MOCS)?
OHCs - more efficient at lows and mids
52
What is the primary function of the lateral superior olivary complex (LSOC)?
IHCs
53
what stimulus is best to evoke TEOAEs
brief/transient click containing a BB frequencies played over and over and averaged
nonlinear because the cochlea is nonlinear
54
what frequency range is mostly tested with TEOAEs
1-4 kHz
55
PL of TEOAEs
74-83 dB SPL
56
in TEOAEs it is more likely to get responses if the rejection rate (No HI) is high and the accepted sweeps is low
false
57
What to report with absent OAEs but flat tymps
TEOAEs were measured and were not present at the time of testing however the middle ear pathology occurring with the type B tymps cannot be ruled out as the cause and cochlear function cannot be determined
58
how to recognize present TE & DPOAEs
DP/Absolute >-10
SNR >6
59
sounds generated by the cochlea, specifically by the outer hair cells, in response to two simultaneously presented pure tones of different frequencies (f1 and f2)
DPOAEs
60
response coming back out from DPOAEs
DP
at the frequency 2f1-f2 (1.22)
61
What are the two pure tones labeled as in DPOAEs
L1 & L2
62
In a normal system what should happen
in suppression OAEs
Decrease in amplitude in the presence of noise mediated by the medial olivcochlear efferents (MOC)
63
CPT code for diagnostic 12 frequency OAEs
92588
64
what frequencies are measured for DPOAEs
500-8000 Hz
Most accurate for 1-6 kHz
65
what dB separation should L1 & L2 be
10 dB
66
How to calculate DP
f1 = 1000 Hz
f2= 1220 Hz
2f1-f2 = 2000-1220
DP = 780 Hz
67
Interpret what this is under the response graph:
68
Are these passing responses? why? is this a DP or TE
yes
>-10 DP and >6 SNR
DPOAE
69
where on this screen can you change parameters for DPs like points per octave, intensity level, test time, passing criteria, noise/artifact rejection?
screw icon to the left right beside the test frequencies
70
Is this showing a good probe insertion or not?
yes
71
Are these passing responses? why? is this a DP or TE
yes
>-10 DP and >6 SNR
DPOAE
72
where on this screen can you change parameters for DPs like points per octave, intensity level, test time, passing criteria, noise/artifact rejection?
screw icon to the left right beside the test frequencies
73
is this a good probe insertion
no
showing it is out of the ear
74
what is the red line under DP-Gram showing?
the DP response across frequencies
75
Suppression is mediated by
medial olivcochlear efferents
76
most common way to suppress OAEs
TEOAEs with BB noise in contralateral ear
can use DPs too
77
level for BBN in suppression
same intensity or 5dB louder than OAE stimulus level
TEOAEs - 74-83 dB SPL
DPOAEs - 55/65
78
interleaving test conditions for suppression OAEs
Stim in one ear alone
Stim with contralateral suppressor
Stim alone
Stim with contralateral
79
Lack of suppression or decrease in amplitude is normal in suppression OAEs
false
abnormal, indicative of ANSD or non-functioning efferent system
80
what is the usefulness of using pressurized OAEs
Middle ear conditions can suppress or distort OAEs and by adjusting the ear canal pressure to match the middle ear pressure (during tymps) you equalize the pressure, allowing for a more optimal testing of the cochlear function
81
Why are LFs the most affected with significant ME pressure?
Fluid in the middle ear results in stiffness in the system, which causes the ME to not vibrate the way it normally does. Stiffness results in a high-pass filter, which eliminates the LFs
82
Why are all frequencies affected with fluid or fixed ossicles
Causes the eardrum to not move at all, resulting in a mass-dominated system causing absent OAEs and all frequencies to be equally affected
83
Evoked (Event-Related Potentials - ERP)
External stimulus is required
Conscious awareness is needed
Example tests → ECochG, ABR
Smaller than EEG & requires
Signal averaging & amplification
84
Non-evoked (Non-Event Related Potentials)
Reflects ongoing brain activity in the absence of stimuli
External timulus is not required; spontaneous
No conscious awareness is needed
Recorded as EEG
85
Inverting Electrode
on earlobe or mastoid of the stimulus side (A1 or A2)
Polarity of the signal coming from this electrode IS inverted
Takes the AEP coming into the electrode and before signal processing happens it flips the whole thing 180 deg into the mirror image reference
The signal flipping causes phase cancellation and leaves us with the signal of interest
86
Non-Inverting Electrode
electrode located on Cz or midline forehead near Fz
Polarity of the signal coming from this electrode is NOT inverted
Takes AEP signal coming into the electrode, goes into pre-amp box and signal processing, is analyzed and stays the same → how it comes in is how it stays and there is no manipulation of the signal
87
what impedances do we want for running any AEP and interelectrode impedances
overall impedances ≤3-5 kohms
Less than 2kohms between electrodes\
88
what to do if impedances are high
Press on the electrodes
Move them with prepped skin
Add more conducting paste or gel
Add additional tape to secure them
Remove and re-prep the skin in the same area
braid the wires
move electrode leads away from insert leads
89
differences in channels
1-Channel → 3-4 electrodes → basic ABR testing
Good for threshold estimation and more basic clinical needs or screenings; slower
Records 1 ear at a time & gives 1 waveform at a time (e.g., Cz-A1 or Cz-A2)
2-Channel → 4+ electrodes → neurodiagnostic use (gets both ipsi & contra responses)
Allows for simultaneous comparison of responses from each ear or brain hemisphere → helpful in diagnosing retro pathologies
Records both at same time or ipsi & contra, gives 2 waveforms (e.g., Cz-A1 & Cz-A2 together); faster
Used for neurodiagnostic testing, ANSD evals and more detailed; adv diagnostics & differentiating lesions
90
Exogenous response
Elicited by external (environmental) stimuli
ECochG, ABR, OAE, & some ASSR
91
Endogenous response
determined by cognitive processes; later potentials
Requires higher-level processing and awareness
Attention
92
The closer to generator site the worse the response
false
better
93
what is the Interstimulus Interval (ISI)
time bw each stimulus
1s/rate
94
why does ISI matter
Too short = neural elements do not recover and miss or have weak waves
Long enough = full neural recover and have clearer, stronger responses
95
If ISI > refractory period →
neurons fully recover = strong response
96
If ISI < refractory period →
neurons have incomplete recovery = weak or a missed response
97
Uses continuous tone stimulus with variations in amplitude and frequency modulation
ASSR
98
Uses transient stimuli or frequency specific tone burst stimuli
ABR
99
Can be used to estimate hearing thresholds on newborns, non-organic losses or those who cannot perform behavioral testing
ABR and ASSR
100
Can be used for neuro-diagnostic site of lesion testing / neural synchrony
abr
101
Can be used in diagnosis of ANSD
ABR
102
Can detect conductive and mixed hearing losses more easily
ABR
103
Response is based upon amplitude and phase in the frequency domain with an "objective" response detection algorithm
ASSR
104
Response is based on amplitude and latency in a time domain with "subjective" response detection
ABR
105
Use a 1-channel or 2-channel, inverting, non-inverting and ground electrode montage
ABR & ASSR
106
Is better at estimating hearing threshold in the severe to profound range than it's counterpart
ASSR
107
Can be used to detect auditory activity at the brainstem level
ABR & ASSR
108
Can be used to detect auditory activity at the cortical level (auditory cortex)
ASSR
109
Is often performed binaurally at the same time with multi-frequencies
ASSR
110
Is measured in microvolts (millionths of a volt) which is larger in scale than its counterpart
ABR
111
Can be used in soundfield for functional gain testing
ASSR
112
Why do we use ECochG
assesses inner ear function, especially in cases of suspected endolymphatic hydrops and in diagnosis of 3rd window disorders (SSCD)
113
generators of CMs
OHCs, immediate onset, follows the wave stimulus that evokes it (alternating signal)
114
ECochG Base
Reference point for amplitude measurement (onset of ECochG response)
115
summating potential
Primarily inner hair cell activity and distortion products of basilar membrane w/ possible stria vascularis and OHC contributions
116
Action Potential
Distal VIIIth nerve (spiral ganglion) response
Same as wave I of the ABR
117
advantages of ECochG
Not affected by arousal and attention, immune to most drugs and medications (no effects from sedatives, anesthesia, relaxants, barbiturates)
*affected by Phenytoin, lidocaine and diazepam
118
describe the protocol for ECochG
stim: click at 90dB
alternating polarity
5-10ms EPOCH
slow rate (8.1/s)
119
what transducers are these?
a - tiptrode
b: tymptrode
C. transtympanic
120
in ecochg if you are getting poor waveforms what can you do to enhance them
Use slower rate, higher intensity and move electrodes deeper in the canal
121
present ECochG
normal SP-AP Ratio = good cochlear function
AP amplitude is much larger than SP (2x)
122
absent ECochG
no SP-AP Ratio measured = cochlear pathology or too much HL
Sensory hearing impairment mainly affecting HF region (>1 kHz)
123
elevated ecochg
SP elevation = Meniere’s/hydrops/build up of endolymph & Third Window Disorder or SCD (superior canal dehiscence)
124
why does the SP elevate causing reduced SP/SP ratio (atypically large SP)?
labyrinth swells, increase potential, sp landmark elevates and the ratio increases; same with third window, change in pressure in BM, elevated ratio
125
significant ECochG value for tiptrodes
>50% = abnormal
126
which one of these is labeled correctly
A
127
abr is Not a test of hearing; test of neural synchrony
true
128
waht are the two main types of ABR & their clinical applications of ABRs
Threshold ABR
NBHS, difficult to test individuals, NOHL, poor test agreement
cochlear pathologies, ANSD, & NOHL
neurological assessment/rate study ABR
Integrity of the auditory system
asymmetric or sudden hearing loss, unilateral tinnitus, poor word recognition relative to tonal thresholds and/or abnormal acoustic reflex patterns
129
ABR becomes adult-like by
2-3yrs
130
absolute latencies of waves I, III, V
1.5
3.5
5.5
131
interpeak latencies
I-III
III-V
I-V
Wave I - III: ≈ 2.0 msec
Wave III-V: ≈ 2.0 msec
Wave I-V: ≈ 4.0 msec
132
Interaural latency differences
<0.2-0.4 = normal (wave V comparisons from each ear)
abnormal/delay in 1 ear = retrocochlear lesion
133
CHL presentation on ABR
All absolute latencies are delated/shifted ot the right but interwaves are not affected
*need BC ABR to determine from retro on LIF
134
Retrocochlear presentation on ABR
Wave V latency prolongation (same as CHL)
earlier peaks (I and/or III) may be within normal limits
135
parameter setup for neurodiagnostic/rate study
click
85 dB nHL
condensation
slow rate (27.7), medium (57.7), fast (77.7)
run 1000 sweeps
replcate 2x
10-12ms epoch
*called US Neurorate Study
136
when are neurodiagnostic/rate studies used
Performed in asymmetric or sudden hearing loss, unilateral tinnitus, poor word recognition relative to tonal thresholds and/or abnormal acoustic reflex patterns
determining the presence or absence of a disorder (limited extent) & site of disorder (i.e., cochlear or retro)
137
when are threshold abrs used
Used to estimate hearing sensitivity and evaluate for ANSD
Looking for the lowest level we can get a reproducible and repeatable wave V
performed for newborn hearing assessment, adult hearing assessment (for those that cannot complete traditional testing such as cognitively impaired) and for those with which behavioral thresholds are felt to be unreliable or show poor test agreement
138
parameters for threshold ABR
1. perform clicks
75 dB
rarefaction then condensation to rule out ANSD with rate of 27.7
2. threshold search
start at 500 toneburst
75
27.7 rate
10-12 epoch
repeat for other frequencies
139
How do you prep the patient for electrodes
prep the skin with alcohol pad
use nuprep on gause and wipe down forhead areas, mastoids or in the ear canals with the q-tip if performing ecochgs
140
what is the 10-20 montage for ecochg
non inverting electrode (Cz) on the forehead
ground on the forehead (fpz)
inverting electrodes in the ear canals with the tiptrodes soaked in conductive gel
141
why can we not use faster rates for abr
Refractory periods of CN vii - cant fire that fast
142
what is the dB nHL
Normalize the threshold to the click to an HL
143
What are amplifiers? What is the role of CMR in amplifiers?
*add amplifier image
device that makes small electrical signals big enough to see and measure
AER signals are extremely small (<1 µV) compared to other electrical signals (EEG)
The amps make them visible and measurable
144
What is epoch? Why is this important?
time window after which a stimulus occurs
if this is set inappropriately we cna miss the AEP we are looking to measure
145
Which filter is not recommended for AERs
notch filter
146
latency increases (waves occur later), amplitude decreases (smaller waveforms) and poorer waveform morphology
true
147
What information is needed to set a filter?
frequency
148
What is the term for the technique used in obtaining an adequate signal-to-noise ratio (SNR) in AER recordings?
signal averaging
149
OPEN message when measuring electrode impedances. What is the MOST likely error?
Selecting a two-channel recording option for a one-channel recording montage
150
The auditory evoked response is better at assessing _______________ of the auditory system and the MRI is better at assessing structural problems within the system.
function
151
Based upon the concept of near-field vs far-field responses, for which of the following ABR setups would you expect to obtain the best (largest amplitude, most detail) response?
Inverting electrodes placed against the tympanic membrane (TM-trode or tymptrodes)
152
A click contains energy from many frequencies but correlates best with thresholds in the 2000-4000 Hz range
true
153
are more frequency specific than a click because they are longer duration stimuli than a click
Toneburst or CHIRP stimuli
154
Polarity type where stimulus pressure wave moves toward the tympanic membrane first causing the stapes footplate to move toward the oval window and basilar membrane to move downward
condensation
155
Polarity type where stimulus pressure wave moves away from the tympanic membrane first causing the stapes footplate to move away from the oval window and basilar membrane to move upward
rarefaction
156
Polarity type where stimulus pressure wave is alternated on successive trials
alternating
157
Has the earliest latency of the 3 polarity types
rarefaction
158
Polarity used for ECochG and bone conduction testing
alternating
159
Polarity type that can be split with split buffering feature yielding three responses for a single run
alternating
160
Stimulus polarity type that reportedly produces the largest wave V amplitudes at low levels and may be better for estimating hearing threshold
condensation
161
distal VIII N (spiral ganglion)
f
wave i
162
Proximal portion of the 8 n with some contribution from distal 8 n
wave ii
163
cochlear nucleus and fibers entering the cochlear nucleus
wave III
164
superior olivary complex most likely w/ possibly some contribution from lateral lemniscus and inferior colliculus
wave IV
165
multiple generators but primarily lateral lemniscus and inferior colliculus
wave V
166
If you have noise (artifact) in your EP recordings, list 3 things you can try to improve them.
Tightly braid electrode leads (leads short as possible)
* Impedance equals 5 kohms or less
* Make sure amp cable not crossing over stimulus cable
* Amp at least 3 feet away from the base
* Increase number of averages
* Turn off "noise checking"
* Try another room and/or outlet
* Make sure patient is comfortable and breathing slowly out of mouth
167
when should you mask aer
If wave l is present at normal latency you do NOT need masking
If wave V is delayed and stimulus intensity is greater than 70 dB nHL (or minimum IA value) then contra-lateral masking is required for AC testing.
168
A normal bone-conducted click or tone burst ABR would show missing wave(s)
________ with normal wave V
I-III
169
Which types of electrodes or electrode setups can be used to reliably record ECochG responses?
Tiptrode
Tymptrode (or canal electrode)
Trans-tympanic needle electrode
170
When performing ECochG for diagnosis of endolymphatic hydrops (Meniere's), which of the following would be considered abnormal and suspicious for active hydrops? Assume tiptrode electrode use and conservative (standard) criteria for normal/abnormal.
SP/AP ratio of 45-50% or greater
171
factors or challenges that may limit ECochG reliability in the clinical setting?
Severity of hearing loss (may be difficult to obtain in those with SNHL above 60 dB HL in the 1000-4000 Hz range)
For patients with suspected Meniere's, may be unreliable if they have not been symptomatic in several weeks (most sensitive when recently symptomatic)
ECochG is best when using trans-tympanic needle electrodes or electrodes placed on the TM (TM-Trodes) which is not practical for many patients
172
The ECochG can be abnormal in all the following conditions EXCEPT:
An autoimmune condition causing endolymphatic hydrops
Central auditory processing disorder (CAPD)
Superior semicircular canal dehiscence (SSCD) syndrome
Meniere's Disease
Perilymphatic fistula
capd
173
Sensory gating is best observed using the ____________________ auditory evoked response, because it is considered a “pre-attentive” response and is, therefore, abnormal/absent in patients who have ___________________.
Pb; Schizophrenia
174
An AMLR response would MOST likely be elicited from PT when
stage 1 of sleep, rem sleep, awake, reading
175
In contrast to the ABR, rather than latency, amplitude is a more sensitive diagnostic measure of the middle and late latency auditory evoked responses because
The neural generators of the middle and late responses have no high frequency energy, which makes precise latency resolution less important
The middle and late responses are generated by larger neurons that arise from multiple subcortical and cortical sites exhibiting greater latency variability
176
neural generators in p300
Ventral and dorsal cochlear nuclei
177
50 ms ___________
Pb/P1/P50
178
30 ms _________
Pa
179
40 ms _____
nb
180
20 ms _________
na
181
10 ms ______
po
182
Hemispheric laterality/asymmetry: _____________
amlr
183
ADHD: ____________
p3
184
Benefits of auditory training: _________________
ALR/P1
185
Predisposition to alcoholism: _______
p3
186
Sensory gating: ___________
Pb/P50/P1
187
The _______________ AER is observed in response to semantically inappropriate words
N4/N400
188
what is the 10-20 for abr
can do same as ecochg
or can do vertex, ground, mastoids
189
Best for finding unilateral temporal lesions (cortical auditory dysfunction)
Compares activity from each hemisphere separately
AMLR
190
Protocol for amlr
10-20
2-channel
patient awake
click
<70
100ms epoch
alternating
191
where does pam com in
12-20 ms
192
First ENDOGENOUS response
N2 of ALR
193
p300 set up
10-20
<70
alternating
oddball
500+
slow <1.1/a
194
protocol for AMLR
500 hz toneburst
70 dB nHL
alternating
106.6 epoch
rate 1/s
195
protocol for ALR
1000 Hz tone burst
70
alternating
1.1/s
450ms
196
When would you utilize nonlinear vs linear TEOAEs?
Nonlinear
Cancel out stimulus artifacts which removes lower-level components of the OAE signal
optimized for quick, robust, artifact-free responses in typical hearing screening
Linear
Doesn’t do this and preserves all components ofthe response to allow for better frequency specific information
Longer and gets a richer, more detailed picture of cochlear activity
When to use it
Study the cochlear fine structure
Investigating subtle cochlear dysfunction
-
Key Links
-
Subjects
-
Company
-
Find Us
-
