Characterisation of the Elasticity of the Human Vocal Fold using

Electromechanical Measurement Techniques

Characterisation of the Elasticity of the Human Vocal Fold using

Electromechanical Measurement Techniques

The Linear Skin Rheometer

The Laryngeal Tensiometer

LSR Principle of Operation

Shear Mode Operation

Force ~ Displacement Graph

-2

0

2

4

6

8

10

12

0 0.5 1 1.5 2 2.5

Indentor Mode

Results from Harvard - AQL 2003

Results from Wisconsin - 2005

Typical Experimental Setup

Vocal Fold Shear Modulus - Shear Model

0

500

1000

1500

2000

2500

3000

3500

4000

0 20 40 60 80 100

Age

Pa

sc

al

Female

Male

Vocal Fold Shear Modulus - Indentometer Model

0

500

1000

1500

2000

2500

3000

0 20 40 60 80 100

Age

Pa

sc

al

female

Male

Male FemaleShear 1008 190 1237 384Indent 1000 230 1332 214

Summary of Shear Modulus Results

The Laryngeal Tensiometer

•Show clips now

Shear Strain

-0.4

-0.2

0

0.2

0.4

0.6

0 50 100 150 200 250 300 350

Time

Fo

rce

gra

ms

Methyl Cellulose Attachment

Suction Attachment

Suction

-1

-0.5

0

0.5

1

1.5

2

2.5

time

Gra

ms

Fo

rce

Age Sex CofV Shear ModulusMean Pascals

36 F 15% 93337 F 19% 77728 F 11% 70170 F - 197228 F 10% 181952 F 27% 90163 M 22% 163755 M 17% 2225

Range of Shear Modulus Obtained from 8Volunteer Patients

First Suction results CofV = 3% & 8%

Spinning

0

0.2

0.4

0.6

0.8

1

1.2

0 50 100 150 200

Angle

DSR

Elastic Variance with angle

Complete Vocal Fold

00.20.40.60.8

11.2

0 50 100 150 200

Angle (90 = transverse)

Stif

fnes

s

Anisotropic Behaviour Study

0

0.2

0.4

0.6

0.8

1

1.2

0 50 100 150 200

Ligament & Muscle

0

0.2

0.4

0.6

0.8

1

1.2

0 50 100 150 200

Muscle Only

Complete 0.38

Ligament 0.53

Muscle 0.61

Ratio of Transverse to Longitudinal Stiffness

Implies LP is inherently anisotropic