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1
HST 721 Mouse Lab:Noninvasive Assessment of Cochlear Function
2
DPOAEs
ABRs
Flowchart of the cochlear signal generationDPOAEs assess all structures except IHCs and NeuronsABRs assess all structures
ABRs vs. DPOAEs
3
DPOAEs:Distortion Product Otoacoustic Emissions
4
INP
UT
OUTPUT
DPOAEs: Source of the Nonlinearity
5
Cochlear Location BaseApex
f1
Cochlear Location BaseApex
f1 f2
Cochlear Location BaseApex
f1 f2
2f1-f2
Cochlear Location BaseApex
f1
f22f1-f2
DPOAEs: Place of cochlear generation
6
QuickTime™ and a YUV420 codec decompressor are needed to see this picture.
DPOAEs: Source of Amplification
7
DPOAEs: How they are measured in humans
8
DPOAEs: How they are measured in the lab
9
DPOAEs: How they are measured in the lab
10
DPOAEs: What you will see in mice
-20
-30
-10
0
10
20
30
30
10 20 30 40 50 60 70 80 90
Primary Tone Level (dB SPL)
Noise Floor
DP amplitude vs. level functions in 3 ears1 pair of primaries at many SPLs
Ear-canal spectrum for 1 pairof primaries at 1 SPL
f2f1
2f1-f2
Noise Floor
“Threshold”
11
DPOAEs: What you can compute in mice
DP iso-response functions“Threshold” vs frequency
12
DPOAEs: Assess OHCs and all “upstream elements”
13
ABRs:Auditory Brainstem Responses
1414
Click Stimulus
Single-Fiber
Responses
Compound Action
Potential (CAP)
CAPs: Dominated by auditory nerve response
1515
ABRs: Include potentials from several brainstem nuclei
-
Middle Ear
AuditoryMid-Brain &Brainstem
Auditory Cortex
Inner Ear
Click Stimulus
Auditory Brainstem
Response (ABR)
1616
ABRs: Which cells dominate the peaks ?
-
Middle Ear
AuditoryMid-Brain &Brainstem
Auditory Cortex
Inner Ear
VCN
SOC
1717
ABRs: Tone pips vs. Clicks
1818
Single-Fiber Recordings
ABRs: Frequency selectivity of tone pips
1919
ABRs: Tone pips vs. Clicks
2020
ABRs: Signal Averaging
Noise decreases in proportion to √n,
where n = # averages
Near threshold, 1024 averages are typically
acquired for ABR.
2121
Response amplitude grows with increasing
stimulus SPL
ABRs: What is Threshold?
2222
ABRs: What is Threshold?
Noise floor, and therefore “threshold” is affected by amount
of averaging
Strategy 1:Iso-response criteria
2323
ABRs: What is Threshold?
Noise floor, and therefore “threshold” is affected by amount
of averaging
Strategy 2:Follow the waves
80 1 2 3 4 5 6 7
Normalized Waveforms
Time (msec)
10 dB
15 dB
20 dB
25 dB
30 dB
35 dB
40 dB
45 dB
50 dB
55 dB
60 dB
65 dB
70 dB
75 dB
Threshold
2424
ABRs: What is Threshold?
Even with extensive averaging, ABR/CAP
“Threshold” is > single fiber “Threshold”
2525
ABRs: Signal Averaging
“Artifact Reject” in the software allows
removal of large potentials due to EKG
26
ABRs: How they are measured in the lab
2727
ABRs: How they are measured in the lab
2828
ABRs and DPOAEs:The Laboratory
2929
Ear Canal Surgery
3030
LabVIEW Software Controller: Main Menu
3
Group ID #
ABR ACQUISITION ABR DATA PLOT
EQPT SETUP
QUIT
NEW GROUP
RUN OPTIONS
DP ACQUISITION0
DP RUN #DP DATA PLOT
SETUP OPTIONS(do each only once)
0
ABR RUN #
3131
Software Controller: DPOAE Control & Indicators
4.0
f2 Frequency
15
Start dB
80
Stop dB
5
dB Step
25
#Waves per Spectrum
1. Set Stimuli
2. S tart START
3. Watch Data Acquisition
ABORT
4. Add Notes (Optional)
5. Sav e SAVE DATA
6. Note FilePath
7. Return to Main Menu RETURN
Type stuff here if you want
0
-140
-120
-100
-80
-60
-40
-20
Frequency (Hz)
500001000 10000
Response Spectrum
2
ID #
1
Run #
90
-40
-30
-20
-10
0
10
20
30
50
60
80
Primary Level (dB SPL)
805 10 15 20 25 30 35 40 45 50 55 60 65 70 75
DPOAE Amplitude vs Level
f1
105.46103.25 MAX SPL
f1 f2
1.2513
-1.2199-1.0000
-0.5000
0.0000
0.5000
1.0000
Time (msec)
2.00.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8
Response Waveform
C:\Data\HST721- DATA\HST721-2\DP-2-1
2f1-f2
40
70
f1
f2
2f1-f2
Noise Flr
3232
Software Controller: Data Storage
:RUN-1 DP I-O 3:54 PM:Level Step (dB):5 Start dB: 20 Stop dB: 50# Buffers Averaged: 25Sampling Interval:4 Ear:Right
:NOTES-:CHAMBER-4
:ANALYZED DATA:Command dB Measured f1(dB) Measured f2(dB) 2f1-f2(dB) 2f1-f2Nse(dB)20.00 30.01 19.97 -24.01 -25.3325.00 35.05 24.98 -26.75 -23.7130.00 40.04 30.01 -25.80 -25.4235.00 45.04 35.01 -25.51 -24.8640.00 50.04 40.04 -22.93 -25.0645.00 55.11 45.05 -20.88 -24.5450.00 60.10 50.05 -23.63 -24.94
:RAW WAVEFORMS0.002390 0.003187 0.004161 0.006183 0.009836 0.016199 0.0277110.002397 0.003308 0.004397 0.006392 0.010246 0.016801 0.0288280.002385 0.003362 0.004509 0.006510 0.010535 0.017273 0.029696
etc.
3333
Software Controller: ABR Control & Indicators
START
ABORT
10
START (dB)
80
STOP (dB)
512
# AVERAGES per LEVEL
8.00
FREQUENCY
5
dB STEP
Tone Pip Stimuli
SAVE DATA
35
REP RATE (pips/sec)
15
REJECT THRESH (µV)
2. Start
1. Set Stimuli
5. Save
3. Watch Data Acquisition
4. Add Notes (Optional)
6. Note FilePath:
RETURN7. Return to Main 3
ID #
15
0
5
10
1000 20 40 60 80
Amplitude vs Level
20
-1
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
80 1 2 3 4 5 6 7
1
RUN #
10
8
9
Time (msec)
90 1 2 3 4 5 6 7 8
Current Average
113 MAX SPL
6 # RejectsReject Flag
512 # Averages
80SPL
6
-6
-4
-2
0
2
4
Time (msec)
600 5 10 15 20 25 30 35 40 45 50 55
Stimulus Waveform
Level (dB SPL
C:\Data\HST721- DATA\HST721-3\ABR-3-1
Stacked Waveforms - All Levels
SPLList
3434
Software Controller: Data Storage
:RUN-0 ABR I-O 10/24/2003 4:47 PM: EAR: R FREQ: 16.00 # AVES: 400 REP RATE (/sec): 80 SAMPLING (µsec): 10:NOTES-:CHAMBER-4:SPLs TESTED-20;30;40;50;60;70;80;
:ANALYZED DATA:SPL "NEURAL" P-P "CM" P-P20.000 1.563 1.29630.000 1.587 1.52940.000 1.514 1.01750.000 1.562 1.56660.000 1.820 1.49070.000 2.368 2.67180.000 3.563 4.549
:RAW WAVEFORMS-0.084572 -0.060116 -0.104443 0.059216 0.167206 -0.009075 -0.132732-0.046043 -0.051418 -0.105358 0.054485 0.158127 -0.014187 -0.088329-0.042152 -0.030743 -0.097805 0.046932 0.125854 -0.006329 -0.072536