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Introduction to Auditory Simulation Methods Applicable to NIHL Study
June 22, 2009
Won Joon Song and Jay Kim
Mechanical Engineering Department
University of Cincinnati
Contents
• Network model• Transfer function model• Applicability of simulation models to NIHL
study
Auditory pathways in conventional network models
External ear TM Ossicular
chain Inner ear
Mechanical transmission
Acoustic transmission
Bone conduction
Generally replaced by cochlear input impedance B.C
Modeled as independent block
ME air space
Skull
Schematic of network ear model
Inner Ear
Middle Ear
External Ear
Source
Tympanic membrane
Cochlear input
Concha entrance
Two-port network equivalent to transfer matrix
A B
C D
ZDF
ZRD
2P P
Diffraction effect by head & upper torso
Radiation effect by concha entrance
Ear canal
Concha
Straight tubeReversed horn
ZS1
ZP1
ZS2
ZP2
ZS3 ZSn
ZHZP3
Mass effect by cochlear fluid
Helicotrema
Cochlear partition impedance
ZC0 lumped in middle ear model
Classical middle ear network model
• Tympanic membrane & ossicular chain up to I-S joint
• Two-port network of conductive pathway
• Middle ear cavity• Decoupled from
mechanical pathway
• Stapes complex & cochlear input impedance
• Impedance B.C. for ME transmission
ZSCZTOC
ZC0
ZCAV
ZST
PTM
UTM UST
PST
ZOC
ZTM
Network sub-structures and parameter values are different, but three-impedance-block concept is common in typical network models.
Available outputs from network model
Time-domain response:
Steady state response:
Inner Ear
Middle Ear
External Ear
Source
UST(t) dBM (x, t)PTM (t)
ZME ZC0
HUP (ω)
PC0 (t)
HP (ω) HC (x, ω)
ZEE
HFT(ω)
PFF (t)
HDP (ω)
dST (t)
Limitations of middle ear network models
• Complex vibrational mode of the tympanic membrane: single-piston
or mechanically coupled two-piston modeling
• Rocking motion of the stapes footplate: translational motion only
• Variable middle ear transformer ratio – Moving axis of rotation
– Flexible ossicular joints: rigid M-I joint assumed
– Effective area change in TM and stapes footplate
• Nonlinear acoustic reflex characteristics– Time-frequency dependent
– Threshold, adaptation, and saturation features
• Nonlinear mechanical properties of the annular ligament
• Highly complicated cochlear input impedance: over-simplified
Network model simulation example: Simulink version of AHAAH
Continuous
pow ergui
i+ -
v+ - v
+ -
in out
VestibularVolume
Ue
I
V
Stapes Disp.
Pc
Stapes Disp. [micron]Intracochlear Press [Pa]
Stapes Disp.
in out
Stapes
inout
SourceModel
in out
Round Window
Pe
Pc
in
ou
t
Melleo-Incudal
J oint
simin
Input Data
in out
Incus
in
ou
t
Icudo-Stapedial
J oint
in
ou
t
Helico-trema
V
I
Pe
Ue
Eardrum Press. [Pa]Eardrum Vol. Vel. [cm3/ s]
in
ou
t
Eardrum Independent
in out
EardrumConductive
inout 1
out 2
DiffractionField
i+ -in1
in2
out1
out2
Concha & Ear Canal
in out
ConchaEntrance
in
ou
t
Cochlea
in out
Bulla
in out
AnnularLigament
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18-4
-2
0
2
4
6
8x 10
4
Time [sec]
Ear
drum
Pre
ssur
e [P
a]
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18-20
-15
-10
-5
0
5
10
15
20
Time [sec]
Sta
pes
Dis
plac
emen
t [
m]
TM input pressure Stapes displacement0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18-3000
-2000
-1000
0
1000
2000
3000
4000
5000
6000
7000
Time [sec]
Inpu
t S
ound
Pre
ssur
e [P
a]
Acoustic wave
( )STd t( )TMP t( )FFP t
Nonlinear model block
Network model simulation example: Human cochlear model in AHAAH
BM characteristic freq.-time BM location-time
dST (t) dST (ω) dBM (x,ω) dBM (x,t)FFT IFFTHC (x,ω)
Network model
(Simulink)
Cochlear model (Matlab)
Transfer function method: An alternative to network model
• Free from modeling
artifacts
• Wider valid frequency
range
• Responses only up to
stapes
• Linear concept
Inner Ear
External Ear
Source
( ) TMFT
FF
PH
P ( ) ST
UPTM
UH
P
( )
( )ST
FF
U
P
Middle Ear
Replaced by measured TFs
Transfer function method: Stapes response calculation
( )( ) ( )
( )ST
FT UPFF
UH H
P
( ) ( )( ) ( ) ST FF
ST FFST
U PD P
j A
( )STd t
( )FFP tFFT
TF from free-field sound pressure to stapes volume velocity
Stapes response in frequency domain
Stapes response in time domain
IFFT
( )( ) ( )
( )ST
ST FFFF
UU P
P
( )STu t
Available transfer functions
Human
HFT
HUP
Chinchilla Guinea pig Cat
Shaw, E. A. G. (1974)**Mehrgardt & Mellert (1977)
Bismarck & Pfeiffer (1967)*Murphy & Davis (1998)
Sinyor & Laszlo (1973)**
Wiener et al. (1965)**
Ruggero et al. (1990)
Guinan & Peake (1967)
Nuttall (1974)Kringlebotn & Gundersen (1985)
( )( )
( )TM
FTFF
PH
P
( )
( )( )
STUP
TM
UH
P
* Azimuth: 0°** Phase data not available
Currently available data: Magnitude of HFT
101
102
103
104
-10
0
10
20
Frequency (Hz)
CH
: P TM
/PFF
(dB
)
101
102
103
104
-10
0
10
20
Frequency (Hz)
CH
2:
P TM/P
FF (
dB
)
101
102
103
104
-10
0
10
20
Frequency (Hz)
CT
: P TM
/PFF
(dB
)
101
102
103
104
-10
0
10
20
Frequency (Hz)
GP
: P TM
/PFF
(dB
)
101
102
103
104
-10
0
10
20
Frequency (Hz)
HM
: P TM
/PFF
(dB
)
101
102
103
104
-10
0
10
20
Frequency (Hz)
HM
2:
P TM/P
FF (
dB
)
Chinchilla: Bismarck & Pfeiffer (1967)
Chinchilla: Murphy & Davis (1998)
Cat: Wiener et al. (1965)
Guinea pig: Sinyor & Laszlo (1973)
Human: Shaw (1974) Human: Mehrgardt & Mellert (1977)
Currently available data: Phase of HFT
101
102
103
104
-6
-4
-2
0
2
Frequency (Hz)
CH
2:
PTM
/PFF
(period)
101
102
103
104
-1.5
-1
-0.5
0
0.5
Frequency (Hz)H
M2:
PTM
/PFF
(period)
Chinchilla: Murphy & Davis (1998)
Human: Mehrgardt & Mellert (1977)
Currently available data: Magnitude of HUP
101
102
103
104
0
0.5
1
x 10-4
Frequency (Hz)
HUP
CH (
cm5 /d
yne s
ec)
101
102
103
104
0
0.5
1
x 10-4
Frequency (Hz)
HUP
CT (
cm5 /d
yne s
ec)
101
102
103
104
0
0.5
1
x 10-4
Frequency (Hz)
HUP
GP (
cm5 /d
yne s
ec)
101
102
103
104
0
0.5
1
x 10-4
Frequency (Hz)
HUP
HM (
cm5 /d
yne s
ec)
101
102
103
104
0
0.5
1
x 10-4
Frequency (Hz)
HUP
HM2 (
cm5 /d
yne s
ec)
Chinchilla: Ruggero et al. (1990)
Cat: Guinan & Peake (1967)
Guinea pig: Nuttall (1974)
Human: Kringlebotn & Gundersen (1985); Rosowski (1994)
Human: Kringlebotn & Gundersen (1985); Rosowski (1991)
Currently available data: Phase of HUP
101
102
103
104
-0.6
-0.4
-0.2
0
0.2
0.4
Frequency (Hz)
HUP
CH (
period)
101
102
103
104
-0.4
-0.2
0
0.2
0.4
Frequency (Hz)
HUP
CT (
period)
101
102
103
104
-0.1
0
0.1
0.2
0.3
Frequency (Hz)
HUP
GP (
period)
101
102
103
104
-0.6
-0.4
-0.2
0
0.2
0.4
Frequency (Hz)
HUP
HM (
period)
101
102
103
104
-0.6
-0.4
-0.2
0
0.2
0.4
Frequency (Hz)
HUP
HM2 (
period)
Chinchilla: Ruggero et al. (1990)
Cat: Guinan & Peake (1967)
Guinea pig: Nuttall (1974)
Human: Kringlebotn & Gundersen (1985); Rosowski (1994)
Human: Kringlebotn & Gundersen (1985); Rosowski (1991)
Transfer function reconstruction
• Target– Spectral range up to 25 kHz– Species: human and chinchilla (due to insufficient data
for guinea pig and cat)
• Within measured frequency range– Approximated by spline function passing through the
measured data points
• Out of measured frequency range– Curve-fitting of measured data subset– Extrapolation of the fitted curve
Transfer function reconstruction example: HFT
Human: Mehrgardt & Mellert (1977)
Chinchilla: Murphy & Davis (1998)
Gauss2 (0.96, f<1 kHz)
Poly1 (0.91, f> 8 kHz)
Sin4 (0.97, f<1 kHz)
Fourier6 (0.92, f>15 kHz)
Transfer function reconstruction example: HUP
Human: Kringlebotn & Gundersen (1985); Rosowski (1994)
Chinchilla: Ruggero et al. (1990)
Poly7 (0.99, f<1 kHz)
Exp2 (0.99, f>1 kHz)
Poly5 (0.99, f<1 kHz)
Power2 (0.84, f>1 kHz)
Reconstructed transfer function
Chinchilla
Human
0 0.2 0.4 0.6 0.8 1-150
-100
-50
0
50
100
150
Time [sec.]
PFF
[dy
ne/c
m2 ]
0 0.2 0.4 0.6 0.8 1-0.02
-0.01
0
0.01
0.02
Time [sec.]
u st [
cm3 /s
ec]:
HM
0 0.2 0.4 0.6 0.8 1-0.02
-0.01
0
0.01
0.02
Time [sec.]
u st [
cm3 /s
ec]:
HM
2
0 0.2 0.4 0.6 0.8 1-0.02
-0.01
0
0.01
0.02
Time [sec.]
u st [
cm3 /s
ec]:
CH
TF model simulation example:Stapes response to complex noise
Human
Chinchilla
Complex (G-44)
( )STd t( )STu t
0 0.2 0.4 0.6 0.8 1-150
-100
-50
0
50
100
150
Time [sec.]
PFF
[dy
ne/c
m2 ]
0 0.2 0.4 0.6 0.8 1-0.02
-0.01
0
0.01
0.02
Time [sec.]u st
[cm
3 /sec
]: H
M
0 0.2 0.4 0.6 0.8 1-0.02
-0.01
0
0.01
0.02
Time [sec.]
u st [
cm3 /s
ec]:
HM
2
0 0.2 0.4 0.6 0.8 1-0.02
-0.01
0
0.01
0.02
Time [sec.]
u st [
cm3 /s
ec]:
CH
0 0.2 0.4 0.6 0.8 1-150
-100
-50
0
50
100
150
Time [sec.]
PFF
[dy
ne/c
m2 ]
0 0.2 0.4 0.6 0.8 1-2
-1
0
1
2
3x 10
-5
Time [sec.]
d st [
cm]:
HM
0 0.2 0.4 0.6 0.8 1-2
-1
0
1
2
3x 10
-5
Time [sec.]
d st [
cm]:
HM
2
0 0.2 0.4 0.6 0.8 1-3
-2
-1
0
1
2
3x 10
-5
Time [sec.]
d st [
cm]:
CH
TF model simulation example:Stapes response to impulsive noise
0 0.05 0.1 0.15 0.2-4
-2
0
2
4
6
8x 10
4
Time [sec.]
PFF
[dy
ne/c
m2 ]
0 0.05 0.1 0.15 0.2-2
0
2
4
6
Time [sec.]
u st [
cm3 /s
ec]:
HM
0 0.05 0.1 0.15 0.2-2
0
2
4
6
Time [sec.]
u st [
cm3 /s
ec]:
HM
2
0 0.05 0.1 0.15 0.2-2
0
2
4
6
Time [sec.]
u st [
cm3 /s
ec]:
CH
Human
Chinchilla
Test impulse
0 0.05 0.1 0.15 0.2-4
-2
0
2
4
6
8x 10
4
Time [sec.]
PFF
[dy
ne/c
m2 ]
0 0.05 0.1 0.15 0.2-2
0
2
4
6
Time [sec.]u st
[cm
3 /sec
]: H
M
0 0.05 0.1 0.15 0.2-2
0
2
4
6
Time [sec.]
u st [
cm3 /s
ec]:
HM
2
0 0.05 0.1 0.15 0.2-2
0
2
4
6
Time [sec.]
u st [
cm3 /s
ec]:
CH
( )STd t( )STu t
0 0.05 0.1 0.15 0.2-4
-2
0
2
4
6
8x 10
4
Time [sec.]P
FF [
dyne
/cm
2 ]0 0.05 0.1 0.15 0.2
-0.01
0
0.01
0.02
0.03
Time [sec.]
d st [
cm]:
HM
0 0.05 0.1 0.15 0.2-0.01
0
0.01
0.02
0.03
Time [sec.]
d st [
cm]:
HM
2
0 0.05 0.1 0.15 0.2-0.01
0
0.01
0.02
0.03
0.04
Time [sec.]
d st [
cm]:
CH
±20μm
Velocity-based metric Displacement-based metric
Application to NIHL study: Auditory response metric
Network / TF model
EARM curveNIHL study
1
0
1( , ) ( , ) ( )
T
em ST thu u t u dtT
20
1( ) ( , )
T
eq STu u t dtT
20
1( ) ( , )
T
eq STd d t dtT
1
0
1( , ) ( , ) ( )
T
em ST thd d t d dtT
Questions?
