Introduction to Auditory Simulation Methods Applicable to NIHL Study

Introduction to Auditory Simulation Methods Applicable to NIHL Study

June 22, 2009

Won Joon Song and Jay KimMechanical 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 EarSource

Tympanic membrane

Cochlear input

Concha entrance

Two-port network equivalent to transfer matrix

A BC D

ZDF

ZRD

2P P

Diffraction effect by head & upper torso

Radiation effect by concha entrance

Ear canalConcha

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 EarSource

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

IV

Stapes Disp.Pc

Stapes Disp. [micron]Intracochlear Press [Pa]Stapes Disp.

in out

Stapes

inout

SourceModel

in out

Round Window

Pe

Pc

inou

tMelleo-Incudal

J oint

siminInput Data

in out

Incus

inou

t

Icudo-Stapedial

J oint

inou

t

Helico-trema

VI

PeUe

Eardrum Press. [Pa]Eardrum Vol. Vel. [cm3/ s]

inou

t

Eardrum Independent

in out

EardrumConductive

inout 1out 2

DiffractionField

i+ -in1in2

out1out2

Concha & Ear Canal

in out

ConchaEntrance

inou

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 Sou

nd P

ress

ure

[Pa]

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 EarSource

( ) TMFT

FF

PHP

( ) STUP

TM

UHP

( )( )

ST

FF

UP

Middle Ear

Replaced by measured TFs

Transfer function method: Stapes response calculation

( ) ( ) ( )( )

STFT UP

FF

U H HP

( ) ( )( ) ( ) ST FFST FF

ST

U PD Pj 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

( )( ) ( )( )

STST FF

FF

UU PP

( )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)

( )( )( )

TMFT

FF

PHP

( )( )( )

STUP

TM

UHP

* 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/P

FF (d

B)

101

102

103

104

-10

0

10

20

Frequency (Hz)

CH

2: P TM

/PFF

(dB

)

101

102

103

104

-10

0

10

20

Frequency (Hz)

CT:

P TM/P

FF (d

B)

101

102

103

104

-10

0

10

20

Frequency (Hz)

GP

: P TM/P

FF (d

B)

101

102

103

104

-10

0

10

20

Frequency (Hz)

HM

: P TM/P

FF (d

B)

101

102

103

104

-10

0

10

20

Frequency (Hz)

HM

2: P TM

/PFF

(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: P TM

/PFF

(per

iod)

101

102

103

104

-1.5

-1

-0.5

0

0.5

Frequency (Hz)H

M2:

P TM/P

FF (p

erio

d)


Human: Mehrgardt & Mellert (1977)

Currently available data: Magnitude of HUP

101

102

103

104

0

0.5

1

x 10-4

Frequency (Hz)

H UPCH (c

m5 /dyn

e sec

)

101

102

103

104

0

0.5

1

x 10-4

Frequency (Hz)

H UPCT (c

m5 /dyn

e sec

)

101

102

103

104

0

0.5

1

x 10-4

Frequency (Hz)

H UPGP (c

m5 /dyn

e sec

)

101

102

103

104

0

0.5

1

x 10-4

Frequency (Hz)

H UPHM (c

m5 /dyn

e sec

)

101

102

103

104

0

0.5

1

x 10-4

Frequency (Hz)

H UPHM2 (c

m5 /dyn

e sec

)

Chinchilla: Ruggero et al. (1990)

Cat: Guinan & Peake (1967)

Guinea pig: Nuttall (1974)

Human: Kringlebotn & Gundersen (1985); Rosowski (1994)


Currently available data: Phase of HUP

101

102

103

104

-0.6

-0.4

-0.2

0

0.2

0.4

Frequency (Hz)

H UPCH (p

erio

d)

101

102

103

104

-0.4

-0.2

0

0.2

0.4

Frequency (Hz)

H UPCT (p

erio

d)

101

102

103

104

-0.1

0

0.1

0.2

0.3

Frequency (Hz)

H UPGP (p

erio

d)

101

102

103

104

-0.6

-0.4

-0.2

0

0.2

0.4

Frequency (Hz)

H UPHM (p

erio

d)

101

102

103

104

-0.6

-0.4

-0.2

0

0.2

0.4

Frequency (Hz)

H UPHM2 (p

erio

d)


Cat: Guinan & Peake (1967)

Guinea pig: Nuttall (1974)



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)


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



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

[dyn

e/cm

2 ]

0 0.2 0.4 0.6 0.8 1-0.02

-0.01

0

0.01

0.02

Time [sec.]

u st [c

m3 /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 [c

m3 /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 [c

m3 /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

[dyn

e/cm

2 ]

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 [c

m3 /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 [c

m3 /s

ec]:

CH

0 0.2 0.4 0.6 0.8 1-150

-100

-50

0

50

100

150

Time [sec.]P

FF [d

yne/

cm2 ]

0 0.2 0.4 0.6 0.8 1-2

-1

0

1

2

3x 10

-5

Time [sec.]

d st [c

m]:

HM

0 0.2 0.4 0.6 0.8 1-2

-1

0

1

2

3x 10

-5

Time [sec.]

d st [c

m]:

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 [c

m]:

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

[dyn

e/cm

2 ]

0 0.05 0.1 0.15 0.2-2

0

2

4

6

Time [sec.]

u st [c

m3 /s

ec]:

HM

0 0.05 0.1 0.15 0.2-2

0

2

4

6

Time [sec.]

u st [c

m3 /s

ec]:

HM

2

0 0.05 0.1 0.15 0.2-2

0

2

4

6

Time [sec.]

u st [c

m3 /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

[dyn

e/cm

2 ]

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 [c

m3 /s

ec]:

HM

2

0 0.05 0.1 0.15 0.2-2

0

2

4

6

Time [sec.]

u st [c

m3 /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 [d

yne/

cm2 ]

0 0.05 0.1 0.15 0.2-0.01

0

0.01

0.02

0.03

Time [sec.]

d st [c

m]:

HM

0 0.05 0.1 0.15 0.2-0.01

0

0.01

0.02

0.03

Time [sec.]

d st [c

m]:

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 [c

m]:

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?

Documents

Introduction to Auditory Simulation Methods Applicable to NIHL Study