An Improved Bionic Ear, Cochlear Implants, new ...
Transcript of An Improved Bionic Ear, Cochlear Implants, new ...
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
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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
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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.
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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.