Prof. Gerard M. O’Donoghue University of Nottingham, UK

Paediatric cochlear implants: challenges and future directions

Current Developments and New Directions In

Pediatric Audiology, Istambul 2011

The best of times ...

Late identification

Delayed diagnosis

Poor amplification

Education : low expectation

No cochlear implants

Public Health Policy

Prostheses

Prostheses - implantable

Overview

Neurobiology of deafness Plasticity into Practice Early cochlear implantation Bilateral CI Medical and surgical aspects Electro-acoustic hearing / ABI etc Turkish Temple

Human Auditory System

Lost around time of birth Normal morphogenesis Critical gene product (Steel 2009)

50-90% loss of CN neurones

Quality and number of synapses Hyperexcitability (Eggermont 2008)

Ryugo et al 1997

a

a

No sensory system exists in isolation

Non-auditory effects of deprivation – attention, working memory, executive functioning etc

Conel, 1939-1967

-1 Mo. Birth 1 Mo. 3 Mo. 6 Mo.

15 Mo. 2 Years 4 Years 6 Years

Development Human Cortex

Huttenlocher, Dabholkar 1997, J Comp Neurol 387:167-178.

Auditory cortex Visual cortex Prefrontal cortex

1 y. 2 y. 4 y. 6 y. 15 y. Adult Birth -3. M.

Age

Syn

ap

ses /

100 µ

m³

Synaptic Pruning

Synaptic Maturation

Kral and O’Donoghue, New Eng J Med 2010

Cochlear Implants and Brain Plasticity

Cochlear Implants and Plasticity

1.0

0.8

0.6

0.4

0.2

0.0

0.2

Coch

lea-t

o-c

ort

ex c

orr

ela

tion (

r)

Normal Deaf Stim.

Cochleotopic Organisation of Cortex - CI

1.0

0.8

0.6

0.4

0.2

0.0

0.2

Coch

lea-t

o-c

ort

ex c

orr

ela

tion (

r)

Normal Deaf Stim.

(Fallon et al., 2009)

Cochleotopic Organisation of Cortex - CI

Dorman et al 2009

Cross modal reorganisation after CI

Overview

Neurobiology of deafness Plasticity into Practice Early cochlear implantation Bilateral CI Medical and surgical aspects Electro-acoustic hearing / ABI etc Turkish Temple

Plasticity into Practice [ Carol Flexer]

Not about ears: its all about the brain

Prostheses: brain access tools

‘Its not what we hear, its what we do with what we hear’

Plasticity in Practice

46 million words heard by age 4 (Hart and Risley)

20,000 hours listening for reading (Dehaene)

Hearing loss: 3 times exposure to learn new words / concepts (Pittman)

Acoustically favourable conditions

Huttenlocher, Dabholkar 1997, J Comp Neurol 387:167-178.

Auditory cortex Visual cortex Prefrontal cortex

1 y. 2 y. 4 y. 6 y. 15 y. Adult Birth -3. M.

Age

Syn

ap

ses /

100 µ

m³

Synaptic Pruning

46 Million Words

Huttenlocher, Dabholkar 1997, J Comp Neurol 387:167-178.

Auditory cortex Visual cortex Prefrontal cortex

1 y. 2 y. 4 y. 6 y. 15 y. Adult Birth -3. M.

Age

Syn

ap

ses /

100 µ

m³

Synaptic Pruning

46 Million Words

X3

Huttenlocher, Dabholkar 1997, J Comp Neurol 387:167-178.

Auditory cortex Visual cortex Prefrontal cortex

1 y. 2 y. 4 y. 6 y. 15 y. Adult Birth -3. M.

Age

Syn

ap

ses /

100 µ

m³

Synaptic Pruning

Reading 20,000 hours listening

(normally hearing)

Receptive and Expressive standardised language scores

as a function of age of identification for children with

'normal cognition' (Yoshinago-Itano, 1999)

Receptive

<6m

>6m

Expressive

<6m

>6m

Age of identification

40 60 80 100 120

Language quotient

Early intervention

Receptive and Expressive standardised language scores

as a function of age of identification for children with

'low cognition' (Yoshinago-Itano, 1999)

Receptive

<6m

>6m

Expressive

<6m

>6m

Age of identification

40 60 80 100 120

Language quotient

Early intervention

Overview

Neurobiology of deafness Plasticity into Practice Early cochlear implantation Bilateral CI Medical and surgical aspects Electro-acoustic hearing / ABI etc Turkish Temple

Early Cochlear Implantation

Age of implant 0-4 years 2000 to 2010

0%

20%

40%

60%

80%

100%

Benelux France Germany Italy Poland United

Kingdom

Benelux France Germany Italy Poland United

Kingdom

2000 2010

2 to 4 Years

1 to 2 Years

0 to 1 Years

Source: Cochlear Ltd database

Implanted < 1y

40%

60%

80%

100%

2000

Bex Fr Ger It Pol UK

20%

2000

0%

Age at implant 0-4 years 2000 to 2010

0%

20%

40%

60%

80%

100%

Benelux France Germany Italy Poland United

Kingdom

Benelux France Germany Italy Poland United

Kingdom

2000 2010

2 to 4 Years

1 to 2 Years

0 to 1 Years

Source: Cochlear Ltd database

2010 Belx Fr Ger It Pol UK Belx Fr Ger It Pol UK

2000

40%

60%

80%

100%

20%

0%

Age at implant 0-4 years 2000 to 2010

Audiological Certainty

What age?

What measures?

What validity?

Who decides?

Parameters of hearing aid trial

Overview

Neurobiology of deafness Plasticity into Practice Early cochlear implantation Bilateral CI Medical and surgical aspects Electro-acoustic hearing / ABI etc Turkish Temple

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

19

92

19

93

19

94

19

95

19

96

19

97

19

98

19

99

20

00

20

01

20

02

20

03

20

04

20

05

20

06

20

07

20

08

Nu

mb

er

of

bila

tera

l

Nu

cle

us

rec

ipie

nts

European Data - Bilaterals

Source: Cochlear Ltd database

Bilateral implants children 2005:2010

Source: Cochlear Ltd database

0%

20%

40%

60%

80%

100%

Benelux France Germany Italy Poland United Kingdom Benelux France Germany Italy Poland United Kingdom

2005 2010

Bilateral Unilateral

40%

60%

80%

100%

20%

0% Bex Fr Ger It Pol UK Bex Fr Ger It Pol UK

2005

Source: Cochlear Ltd database

0%

20%

40%

60%

80%

100%

Benelux France Germany Italy Poland United Kingdom Benelux France Germany Italy Poland United Kingdom

2005 2010

Bilateral Unilateral

40%

60%

80%

100%

20%

0% Belx Fr Ger It Pol UK Belx Fr Ger It Pol UK

NICE 2009

2010 2005

Bilateral implants children 2005:2010

Bilateral implantation recommended for children & some adults

Simultaneous

Additional contralateral

Bilaterals – UK Provision

National Audit Bilaterals:UK

Localisation

Speech recognition in background noise

Speech

Language

Listening

Parental perception

Quality of life

Surgical data including complications

Overview

Neurobiology of deafness Plasticity into Practice Early cochlear implantation Bilateral CI Medical and surgical aspects Electro-acoustic hearing / ABI etc Turkish Temple

Surgical challenges - BICI

Minimal Access Surgery

Operating time

Anesthesia

Facial nerve injury

Co-morbidity – known or unknown

Electrocautery

Loss vestibular function / residual hearing

Meningitis risk

Overview

Neurobiology of deafness Plasticity into Practice Early cochlear implantation Bilateral CI Medical and surgical aspects Electro-acoustic hearing / ABI etc Turkish Temple

&

Electrical Stimulation Acoustical Stimulation

Hearing aids + Implants

Frequency (kHz)

-10

0

10

20

30

40

50

60

70

80

90

100

110

120

0,125 0,25 0,5 1

Heari

ng L

oss

(dB

HL

)

Lower Limit Upper Limit

1 1,5 2 3 4 6 8 10

Electro-acoustic hearing

Single Side Deafness and CI

CI CROS Aid

Drug and Stem Cell delivery systems

Advances in Implant Technology

Auditory Brainstem Implant

(Lenarz et al , Colletti et al 2006)

Overview

Neurobiology of deafness Plasticity into Practice Early cochlear implantation Bilateral CI Medical and surgical aspects Electro-acoustic hearing / ABI etc Turkish Temple

Temple of Artemis

J. Gravel 2007

J. Gravel 2007

Information and systems give meaning to everything we do; there is no point in going through the motions of providing a service if there are no systems on which to support, record or monitor the process and outcomes Sir Muir Gray 2007

Deafness - not just about hearing loss

Prostheses as brain access tools

Earlier is best - but not a cure!

Bilateral CI - timely, safe, efficient

Combined acoustical and electrical hearing

Audiological certainty - central

Paediatric audiology ‘Temple’

Summary