an improved bionic ear, cochlear implants, new
TRANSCRIPT
Paddy Boyle, Paddy French, Johan Frijns,
Wouter Serdijn, Jeroen Briaire
An Improved Bionic Ear, Cochlear
Implants, new developments
based on bioelectronics
Overview
• Introduction
• The healthy cochlea
• The cochlear implant
• New generation devices
• Summary
Advanced Bionics
• Founded in 1991 by Al Mann
• Request from UCSF – Robert Schindler MD
• Located in southern California
• First implants in Europe in 1993
• Formally part of Boston Scientific
• Now part of Sonova
• Around 800 staff
• 80 in Europe
• European Research Center Hannover
Brain
Cochlea
AdvancedBionics.com
The Cochlea • Basic anatomy
• Around 2.5 turns in the human
• Some 10 mm across
• Coiled to save space rather than for function
• Basal turn separated from the others
• Three dimensional structure
• Elevation significant for higher turns
• Non-uniform change from turn to turn
• 25 to 40 mm length between individuals
Cochlear Function
• Transduction of mechanical to neural
activity
• Tonotopic organization high to low
frequency from base to apex
• Compressive non-linearity of basilar
membrane: 120 dB dynamic range
• Motile outer hair cells (OHC) provide
active tuning mechanism
• Inner hair cells (IHC) do transduction
Cross-section through cochlea
Nauwelaers T, with permission
8
Frequency response
Working of a Healthy ear.
Movement of hair cells inside the
cochlea leads to sense of
hearing.
Anatomy of human ear.
Electrode Array in Position
Cochlear Implant
12
Hearing Instrument
Input-Output function
Input Sound Pressure Level dB SPL
Ou
tpu
t S
ou
nd
Pre
ssu
re L
ev
el
dB
SP
L
Expansion
Linear
Compressed
Clipped
25 40 100
50
65
95
Goals of compression
• Restore normal loudness growth
function
• Maximize audibility of low intensity
sounds
• Avoid discomfort from higher
intensity sounds
Materials Applications
Metal
Titanium Case; Encapsulation
Platinum Electrode
Iridium Electrode
Zirconium Case
Gold Coil; Encaspulation
Non-metal
Ceramic Case; Feedthroughs
Glass Feedthroughs
Silicone rubber Carrier; Encapsulation
Parylene Insulation coating
Teflon Insulation coating
Biocompatibility and Biocompatible
materials.
FDA approved materials used in Cochlear
Implant’s [1]
[1] Cochlear implants: System Design, Integration &
Evaluation, Fan-Gang Zeng, Stephen Rebscher, IEEE Rev
Biomed Eng. January 2008, 115 – 142.
Definition:
“ The ability of the material to perform with an appropriate
host response in a specific application”
Factors considered under Biocompatibility:
• Material properties.
• Host response.
• Material functionality.
• Corrosion, Fatigue, Fracture, Adsorption,
Absorption, Degradation.
• Byproducts generated due to degradation.
• Ability to achieve hermetic isolation.
17
Wannaya Ngamkham
Supervisor : Dr. Ir. W. A. Serdijn
Low power read out
electronics & integration
Electrode design, fabrication
& biological interface
Nishant Lawand
Supervisors : Prof. Dr. P J. French
Prof. Dr. ir. J H M. Frijns
Dr. J. J. Briaire
Complete System
level Optimizations
Ghazaleh Nazarian
Supervisor: Dr. G. N. Gaydadjiev
Framework of Smac-it project.
System
In CI’s, the software frame work running on the speech processor is
composed of: Profiler, Graphical-User-Interface, Compiler, Assembler
and other sub-modules
Electronics
Wavepackages
Microfabricated completely Flexible
Device
“Flexi-Stiff”
Conclusions
• Cochlear implants have restored hearing to many 1000’s of people around the world.
• Present day implants restore hearing but have limited
sound quality due to limited numbers of electrodes
and they miss the lower frequencies.
• Improved electronics, software and implant
technology will lead to a new generation of cochlear
implants with greater sound quality.