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

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DPOAEs: How they are measured in humans

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DPOAEs: How they are measured in the lab

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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

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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