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All Hair Cells Have Two FunctionsMechano-Electrical Transduction
Neurotransmission
Outer Hair Cells Carry Out
Electro-Mechanical TransductionPassive Cochlear Model
Mass
Stiffness
Damping
Mechanical
models
Filtering
Passive
Frequency
ActiveSensorineural Hearing Loss
Mechanisms of sensorineural hearing loss
Congenital malformations (otic capsulemay or may not be involved)
Stria vascularisSpiral ganglion cells
Organ of Corti / hair cells
Presbyacusis (age- related hearing loss)
Noise- induced hearing loss
Loss of OHCs
(12,000 max)
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Normal Cochlea
Auditory
Nerve
Hair
Cells
Hearing-Impaired Apex
Scala Vestibuli
Spiral Ganglion
Organ of
Corti
(Hair Cells)
Bipolar Contacts
Audi tor y
Nerve
Oval Window
Round Window
Electrode
Central
Rib
BaseCochleostomy
(scala tympani)
ClarionTM
Cochlear
Implant
Common Components of all CochlearImplant Systems
Microphone & Cable
Speech Processor
Antenna/Transmitter
Receiver/Stimulator
Electrode Array
Nucleus 3 system
1
Sound entersmicrophone onheadpiece
2
Sound travelsdown cable toprocessor
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3
Processed soundtravels back up
cable toheadpiece
4
Processed soundis transmitted to
implant throughskin
5
Implant sendssound to cochleathroughelectrode
6
Electrode incochleastimulatesauditory nerve
Advances in ImplantTechnology
Technological advances have resulted inimprovements in patient performance
In turn, improvements in patientperformance have resulted in expandedaudiological criteria!
Optimal Electrode Placementat Medial Wall
LATERAL MEDIAL
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Advances in Electrode Design
Spiral Electrode
(1990)
Spiral Electrodewith PositioningSystem (EPS)
(1998)
HiFocus Electrodewith PositioningSystem (EPS)
(1999)
CLARION & POSITIONER17 mm insertion 630
CLARION ELECTRODE
24 mm insertion 500
Design changes implemented so that
the electrode closely hug the modiolus
Positioner
Mean Most Comfortable LevelsThree Electrode ConfigurationsMonopolar Pulsatile Stimulation
100
150
200
250
300
350
400
1 2 3 4 5 6 7 8Channel Number
ClinicalUnits
Spiral alone at3 months(n=51)
Spiral + EPS at1 month (n=20)
HiFocus+EPSat 1 month(n=34)
Nucleus Contour Electrode
Stylet in place
Stylet removed
K117L, 12.5 mm el. #1
Insertion tr auma: K117L, 11.5 mm el. #2Insertion trauma: K117L, 11.5 mm el. #2
SGSG
SGSGOSLOSL
Slide from Pat L eake, UCSF
SpLSpL
RMRM
ContourContourTM
ElectrodeElectrodeSpGSpG
OSLOSL
OticOtic
capsulecapsule
Slide from Pat L eake, UCSF
SpGSpG
OSLOSL
ElectrodeElectrode
ScSc TymTym
Sc VestSc Vest
Slide from Pat L eake, UCSF
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SpLSpL
RMRM
ElectrodeElectrode
PositionerPositioner
OSLOSL
SpGSpG
HiFocusHiFocus
OticOtic
CapsuleCapsule
Slide from Pat L eake, UCSF
External Equipment
Speech Processors Automatic, Continuous
Functionality Check of AllExternal and InternalComponents
Multiple Indicator Lights
Programmable Acoustic Alarm
ESD Resistant
Easy to Adjust Controls
> Built-in microphone tester
> Multiple Signal-to-Noise ratiooptions for FM/Accessories
mini-computer
BTE Sound Processor
8 Runs all processingstrategies plus new onesunder development
8 Rechargeable batteries forlow operating cost
8 Compatible with allCLARION internal implants
8 Same functionality as Bodyworn PSP, except nowarning lights/alarms
8 Check functionality withSensor
Clarion
Nucleus
CLARION Sound Processor Development
13
100
S-Series Platinum Series & BTE
Million Instructions Per Second (MIPS)
Continuous Two-Way Telemetry
Ongoing monitoringachieved with twodistinct carrierfrequencies
Normal concurrentsignal operation
Benefit forchildren who areunable tocommunicate
Power
& Data
Back
Telemetry
Headpiece ICS
SP Status Indicator
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Input Dynamic Range (IDR)
The normal earcaptures widelyfluctuating speech
intensities rangingover 50 dB as wellas speech fromtalkers when theyare far away orspeaking softlyCLARION capturesthe widest range ofincoming soundsthrough itselectronics andsoftware
CLARION
60 dB IDR
Industrynorm
30 dBIDRNormal
Hearing120 dB
50 dBPeaks
& Valleysof Speech
30
90
70
50
Narrowed IDR (30 dB)Narrowed IDR (30 dB)
Per
ceptualDR
(
PerceptualDR
(uAuA))
Sound
Pressure
Level(dB
SPL)
Sound
Pressure
Level(dB
SPL)
IDR T
M
AGCAGC
Speech ProcessorSpeech Processor ElectrodeElectrode
30
90
70
50
Widened IDR (60 dB)Widened IDR (60 dB)
PerceptualDR
(
PerceptualDR
(uAuA))
Sound
Pressure
Level(dB
SPL)
Sound
Pressure
Level(dB
SPL)
IDR
T
M
AGCAGC
Speech ProcessorSpeech Processor ElectrodeElectrode
Acoustic Signal
Pass band 1 Envelope Compression Ch 1
Pulse Train Carrier
Pass band 2 Envelope Compression Ch 2
Pass band N Envelope Compression Ch N
AGC & Low Pass
high
low
mid
BTE Decals
Six inter-changeable colorheadpiece caps
Nucleus
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Speech Processing
Speech Spectrum
S e n t e n ce
Spectral Resolution (Number ofChannels)
Most important factor is the number ofspectral channels of information
number of distinct pitch channels
Number of effective channels is not thesame as the number of electrodes
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Spectral Cues in Music
While spectral and temporal fine structure are notnecessary for speech recognition they constitutethe very heart of music, i llustrating the differentdemands of speech and music on peripheralsensory processing
Melody recognition requires many more spectralchannels than speech
The cochlea isnt designed for speech thecochlea is designed for music (Ed Burns)
4 8 16 32 Origi nal
Popular Music with male vocal
Processing Strategy and Stimulation Mode
CIS
MonopolarSAS
Enhanced Bipolar
Ch. 1
Ch. 2
Ch. 3
Ch. 4
Ch. 5
Ch. 7
Ch. 8
Ch. 6
MPSMPSBipolar or MonopolarBipolar or Monopolar
Who is a CI Candidate?
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Who Should Get a Cochlear Implant?Children
Children aged 12 mos-17 years
Profound sensorineural hearing loss of 90 dB or greater
in both ears (No Response ABR) Lack of benefit from high powered hearing aids
3-6 month Required Hearing Aid Trial < 2 on Questions 3, 5, & 6 on the IT-MAIS
Questionnaire
Older child (>6yrs): Some auditory skills 0-20% on tests of open-set word recognition (PB-K or MLNT)
Dont Wait!The Younger the Better!
Who Should Get a Cochlear Implant?Children
Rehabilitative or educational setting wheredevelopment of listening and speakingskills are emphasized
Positive family environment where deviceuse through listening and speaking isencouraged
AdultsWho Should Get a Cochlear Implant?
Healthy adult over 18 years of age, no upper agelimit
Severe-Profound sensorineural hearing loss of 70 dBor greater in both ears
Postlingual onset of deafness (after age 6 yrs)
Prelingual adults that are members of the hearingcommunity (lip readers, verbal intent)
Lack of benefit from hearing aids
HINT Sentence score < 50%
Adult Referral Criteria
PTA of >70dB in Both Ears
Monosyllabic Word score of < 30%in Both Ears
Audiological Measurement:CI Candidate?
250 500 1000750 1500 2000 4000 6000 8000-10
010
2030
40
50
Hz
60
70
80
90
100
110
120
dB
X X
XX
XX
86 Yr. Old Adult
PTA=103dB AS
PTA=105dB AD
CNC Words:
=0% AS =0% AD
O
OO
O
O
O
X
CI CI CI CI CI
YESAudiological Measurement:
CI Candidate?
250 500 1000750 1500 2000 4000 6000 8000-10
010
2030
40
50
Hz
60
70
80
90
100
110
120
dB
X
X
XX
X
X
56 Yr. Old Adult
PTA=83dB AS
PTA=75dB AD
CNC Words
=12% AS =16% AD
O
OO
O
O
O
X
XO
YES
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Evaluation&
Expectations
Adult Evaluation: Pre-Operative
Thorough Audiological assessment to determinedegree and type of hearing loss and amount ofbenefit from acoustic amplification
Include OAEs &/or Acoustic Reflex Testing
Medical work up, including CT scan or MRI
Counseling for realistic expectations
Cochlear Implant Surgery
About 2.5 hours General anesthesia, Outpatient Procedure
Incision Drill facial recess Trough for electrode lead Bony bed for receiver/stimulator Secure receiver/stimulator with sutures Cochleostomy for electrode insertion Pack with fascia and close incision
Covered by InsuranceDont take NO for an answer
Cochlear Implant Surgery72 year old male with progressive sensorineural hearing loss
A Post-Auricular Incis ion
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Exposure of the Mastoid CortexDrilling the Mastoid and
Countersinking the Implant
Securing the Implant The Facial Recess
Stapes
Round
Window
Facial Nerve
Lateral
SCC
Incus
Placement of the ElectrodeComplications
Hearing loss - in everyone New techniques to reduce HL
Variable outcomes Chorda tympani nerve injury
COMMON
Infections - uncommonFlap necrosis - uncommonTinnitus & Imbalance - usually self limitedFacial nerve injury - congenital abnormalityMENINGITIS - a problem of mythic
proportions
UNCOMMON
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Risk factors for meningitis
Inner Ear MalformationsPrior history of meningitis
Young children (esp.< 5 yrs).
Otitis media
Immune dysfunction
Prior ear surgery
Meningitis in Cochlear Implantation
91 people worldwide (N=60,000) 17 deaths
53 US cases (N= 25,000) Ages 18 mos to 84 yrs; Most under 7 years of
age (n=33) Signs and Sx 6 yrs 50% developed meningitis < 1 year postop
(N=32) 29 Advanced Bionics CLARION (1996;N=7500) 22 Cochlear Nucleus (1985; N=16,500) 2 MED-EL (2001; N=770)
Design Flaws?
Higher incidence with
Clarion positioner
Removed fro m the
market
HF1 electrode now
available without the
positioner
Positioner
Post-Operative Evaluations:Device Fitting and Follow-up
Initial stimulation: 3-6 weeks post surgery
Adjustments maderegularly based onfeedback frompatients, parents,therapists andeducators
Speech perceptionevaluations semi-annually to annually
Evolution of Implant Outcomes
Single-channel implants Sound detection, perception of speech
rhythm, lipreading enhancement
First generation multichannel implants Closed-set word identification, some
open-set sentence recognition; pooropen-set word recognition
Current Expectations
Sound Field thresholds 20-45dB @ 250-6K Hz
Cannot return to Hearing Aid in implanted ear
>80% Postlingual Adults use the telephone
>50% of Postlingual Adults enjoy music
Near peak performance by 3 months!
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Open-Set Speech RecognitionN=56 Postlinguistic Patients
Six-Month Scores
* Note: Only patients who score > 20% on HINT Sentences in quiet are administered
HINT Sentences in n oise.
3%
13%11%
20%
44%
57%
71%
35%
79%
40%
51%
67%
47%
73%
52%
81%
0%
20%
40%
60%
80%
100%
CNC Words CID Sentences HINT in Quiet HINT +10 S/N*
PercentCorrect
Pre
1Month
3Month
6Month
Individual CNC Word Scores at 3 Monthsand Duration of Deafness (n= 67)
High levels of CNC word recognition were achieved bypatients with long as well as short duration ofdeafness.
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 0 1 1 1 1 2 2 2 2 2 3 3 3 6 6 7 7 8 1 0 1 2 1 2 1 5 1 7 2 0 20 21 26 26 28 30 38 43 58
Years of Deafness - Implanted Ear
PercentCorrect
0 00
Mean = 40%
Median = 42%
Individual CNC Word Scores at 3 Monthsand Age at Implant (n=67)
31% of the sample was implanted at > 70 years of age. Someof these older patients show high levels of word recognition atthree months. Others may require more implant experiencebefore they demonstrate open-set word recognition abilities.
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
22 26 28 33 39 40 43 45 46 49 50 52 53 55 56 59 60 61 62 63 65 68 69 71 73 73 75 75 76 78 80 82 84 88
Age at Imp lant (Years)
PercentCorrect
00 0
Mean = 40%
Median = 42%
SPIRAL GANGLION CELL DEGENERATION
FOLLOWING NEONATAL DEAFNESS
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10 11 12
Duration of Deafness (months or years)
< 1 year n = 56
r2 = 0.83 p 2 years n = 11 (6 cats)
GanglionCellDensity
(%n
ormal)
Slide from Pat L eake, UCSF
K117 L, GM1 Stimulated:K117 L, GM1 Stimulated:
5 mm, SG = 80% of normal5 mm, SG = 80% of normalK117R, GM1 Deafened Contr ol:K117R, GM1 Deafened Control :
5 mm, SG = 40% of normal5 mm, SG = 40% of normal
Slide from Pat L eake, UCSF
Why Research Cochlear Implant
Alternatives?
Outcomes with a cochlear implant are
good but not as good as normal hearing
Cochlear implants can not be used for
mild or moderate levels of hearing l oss
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Baylor College of MedicineChul-HeeChoi, Ph.D.Gentiana Wenzel, M.D.
Anpi ng Xia, M.D., Ph.D.Nicola Schug, M.S.
William E. Brownell, Ph.D.Ruth Anne Eatock, Ph.D.Fred Pereira, Ph.D.Peter Saggau, Ph.D.
University of California San FranciscoPat A. Leake, Ph.D.Russell Snyder, Ph.D.
New York UniversityAnil K . Lalwan i, M.D.
Stanford UniversityRobert K. Jackler, M.D.
Rice UniversityBahman Anvari, Ph.D.Robert Raphael, Ph.D.
Johns Hopkins UniversityAlex Spec tor, Ph .D
University of Tuebingen, GermanyMarkus Pfister, M.D., Ph.D.Nicola Schug, M.S.
National Institutes of HealthNational Organization for Hearing Research
Acknowledgments