Download Outer Hair Cell

Simulation of a Cochlear Model
as a Descriptive Tool for
Normal and Abnormal
Auditory Functioning
Miriam Furst-Yust
Azaria Cohen, Vered Weisz, Noam Elbaum, Yaniv
Halmut, Dan Mecrantz, Oren Bahat, and Udi shtalrid
Dept. of Electrical Engineering-Systems
Tel Aviv University
Clinical Audiometric Tests

Audiograms

Speech Discrimination Tests

Otoacoustic Emissions
Audiometric Diagnosis

Conductive or Sensorineural Hearing Loss

Cochlear or Retrocochlear Hearing Loss

Inner Hair Cells or Outer Hair Cells Loss ?

The amount of Outer hair Cell Loss ?
Can a Cochlear model help in
Audiometric Diagnosis ?
The Ear
Traveling Waves

Tonotopic map of the Cochlea
Basilar Membrane Motion +
Outer Hair Cells Amplification
Outer Hair Cell
Cochlear Model
oval
window
scala vestibuli
helicotrema
apex
base
scala
tympani
x
x


round
window
basilar membrane
One dimensional model
Based on fluid dynamics
Outer Hair Cell Model


Electromotile model
OHC adds to basilar membrane pressure
Middle Ear Model
Outer ear
xOW
TM
Pin
Middle ear
Incudostapedial joint
microphone

Piston based model
Oval window
Cochlear Representations of Tones
Cochlear representation
Cochlear Representation of Chirp
Input Signal : Chirp 1-3 KHz
INPUT
OUTPUT
Normal
Cochlea
OHC Loss
Cochlear Representation of a click
Healthy Cochlea
OHC Loss
Stapes
Apex
100u
s
Stimulus
Representation of a word
Input Signal: The word “SHEN”
INPUT
OUTPUT
Normal
Cochlea
OHC
Loss
Cochlear Representation
of a Noisy Word
Input Signal: The word “SHEN” with Noise
INPUT
OUTPUT
Normal
Cochlea
OHC
Loss
Otoacoustic Emission
Introducing cochlear “roughness”
Model Prediction:
Excitation Patterns
Normal Cochlea
Damaged Cochlea
No Active Outer Hair Cells
Estimated Audiograms
Normal OHC activity
Partial damaged OHC
No OHC activity
Estimated Audiograms
Simulated Audiograms
Normal OHC activity with “roughness”
Partial OHC activity with “roughness”
Damaged cochlear response
Partial OHC Loss
Measured Audiogram

Model Prediction
Non Linear Properties
Loudness.Stimuli Frequency=4000Hz
0
Estimated Loudness [dB]
Gamma=0.5
Gamma=0.3
Gamma=0.1
Gamma=0
-50
-100
-150
0
20
40
60
80
Stimuli Amplitude [dB]
100
120
140
Equal Loudness Countours
Gamma=0.25
Input Stimulus Level (dB)
Gamma=0
Gamma=0.5
140
140
120
120
120
100
100
100
80
80
80
60
60
60
40
40
40
20
20
20
0
0
0
-20
2
10
3
10
Frequency (kHz)
-20
2
10
140
3
10
Frequency (kHz)
-20
2
10
Ld=60
Ld=55
Ld=50
Ld=45
Ld=40
Ld=35
Ld=30
Ld=25
Ld=20
Ld=15
Ld=10
Ld=5
Ld=0
3
10
Frequency (kHz)
Non Linear Respomse
D=2.3cm CF=488Hz
D=1.8cm CF=1074Hz
50
3
60dB
80dB
100dB
120dB
140dB
50
3
10
Frequency [Hz]
Gamma=0
60dB<Amp<100dB
120dB
100
140dB
50
0
2
10
Velocity Gain [dB]
10
Frequency [Hz]
Gamma=0.25
100
0
2
10
Velocity Gain [dB]
60dB
80dB
100dB
120dB
140dB
100
3
10
Frequency [Hz]
Velocity Gain [dB]
Velocity Gain [dB]
Velocity Gain [dB]
Velocity Gain [dB]
Gamma=0.5
0
2
10
‫טון בודד – פילטרים‬
100
50
0
2
10
40dB
60dB
80dB
100dB
120dB
140dB
Gamma=0.5
3
10
Frequency [Hz]
Gamma=0.25
40dB
60dB
80dB
100dB
120dB
140dB
100
50
0
2
10
3
10
Frequency [Hz]
Gamma=0
40dB<Amp<100dB
100
120dB
140dB
50
0
2
10
3
10
Frequency [Hz]

Basilar Membrane Gain
Response to Two Tones:
Combination Tones
Healthy Cochlea
Time
Frequency
Input = 2kHz + 2.44kHz; Equal level