An Update on the Clinical Application of the Nucleus 24 Cochlear Implant

1
An Up-date on the Clinical Application of the
Nucleus 24 Cochlear Implant

• Dr Brian Pyman
• Mr Rod Hollow
• Cochlear Implant Clinic, The Royal Victorian Eye
  Ear Hospital and The University of Melbourne

2
Selection of Candidates
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Patient history and profile

• establish better/worse hearing ear
• history of hearing loss
• etiology and age at onset
• duration of profound deafness
• history of hearing aid/tactile aid use
• speech and language development
• current communication mode needs
• assess functional use of audition

4
Audiometric evaluations

• behavioural techniques
• evoked potential test procedures
• click tone burst ABR
• Steady-State evoked potentials
• otoacoustic emissions
• need for careful correlation between behavioural
  and evoked potential test results

5
Assessment of hearing loss

• severe to profound bilateral hearing loss
• thresholds gt90dB 1KHz and above
• estimates of auditory perception in best-aided
  condition on appropriate test materials
• hearing aid optimisation completed prior to aided
  auditory assessments

6
Assessment of auditory function

• correlate behavioural with evoked potentials
  results
• videotaped assessments of communication important
• include non-verbal behaviour (eg. turn-taking)
• vowel imitation tests
• formal speech tests for older children

7
Problems in assessment

• lack of perceptual ability and experience
• lack of understanding or necessary cognitive
  ability to cooperate with test procedure
• lack of attention and/or cooperation
• lack of sufficient vocabulary and grammar
• middle ear problems giving fluctuating audition

8
Otological and medical considerations

• complete otological assessment
• middle ear problems
• radiological assessment of temporal bones
• x-rays, CT scans
• MRI, 3-D imaging
• other handicaps

9
Speech and language assessment

• naturalistic sampling of interactive play
• conversational samples in older children
• formal videotape procedure with script
• emphasis on how child uses auditory information
• cognitive assessment
• phonemic repertoire, MLU, syntactic analysis,
  pragmatic analysis, intelligibility

10
Pre-operative habilitation program

• develop rapport with parent child
• obtain information about functional use of
  audition
• correlate with audiometric findings
• assess cognitive abilities
• address behavioural issues
• facilitate parent/child interaction

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Pre-operative habilitation program (cont.)

• foster childs use of hearing aids
• extend range of communcation intentions and
  skills
• develop parents abilities to observe, engage and
  reinforce child
• reduce effects of auditory deprivation
• provide time to meet with other parents and
  become familiar with issues

12
Informed consent

• counselling to ensure realistic expectations of
  potential benefits
• individual basis for each patient
• meeting with implant patient
• counselling re potential risks or problems from
  device use or procedure
• counselling re habilitation and long-term use
• counselling re options or alternative devices

13
Key issues to consider

• Residual hearing - severe hearing loss
• Multiple handicaps
• Psychosocial issues
• Needs versus costs
• Need for long-term follow up supporty
• Non-implantable candidates

14
Points to remember

• diagnostic issues are not an impediment to early
  implantation in young children under 2 years.
• parental counselling is critical issue in
  ensuring realistic expectations.

15
The Nucleus 24 Cochlear Implant Preliminary
Clinical Results and Mapping
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Nucleus 24 Cochlear Implant

• Advanced cochlear implant system comprising
• CI24M implant
• SPrint (body-worn) speech processor
• ESPrit (ear-level) speech processor

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CI24M implant

• 22 intra- and 2 extra-cochlear electrodes
• Thin electronics package
• Capable of high stimulation rates (max. 14,300)
• Telemetry function
• MRI compatible

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SPrint speech processor

• Supports advanced speech processing strategies
  (eg SPEAK, CIS, ACE)
• Offers 4 user-selected programs
• LCD display
• Programmable alarms, locks and battery monitor
• Compatible with assistive listening devices

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ESPrit speech processor

• Cosmetic and comfort advantages
• Suitable for older children and adults
• Supports SPEAK and ACE strategies
• Offers 2 user-selected programs

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Preliminary results - SPEAK vs CIS
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Preliminary results - SPEAK vs ACE
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Nucleus 24 preliminary results

• SPEAK vs CIS (N19) SPEAK vs ACE (N15)
• SPEAK gt CIS 32 SPEAK gt ACE 20
• CIS gt SPEAK 26 ACE gt SPEAK 53
• CIS SPEAK 42 ACE SPEAK 27

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Speech perception vs User preference
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Nucleus 24 Mapping

• Monopolar stimulation mode
• low current levels
• more uniform T and C-levels
• Narrow (25 - 50µsec.) pulse widths chosen to
  maximize efficiency
• Software activates initial sensitivity setting,
  volume control, alarms and button lock

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Nucleus 24 Mapping for children

• T-levels
• aim for repeatable responses
• can extrapolate between channels
• C-levels
• initially set conservatively
• later look for repeatable LDLs or train to make
  basic loudness judgements
• Regular Mapping necessary

26
Speech Perception Benefits for Children with
Multiple Disabilities using the Nucleus 22
Cochlear Implant

• R. Hollow, S. Dettman, E. Barker, G. Rance,
• R. Dowell, G. Clark.
• Cochlear Implant Clinic, The Royal Victorian Eye
  Ear Hospital and The University of Melbourne

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Introduction

• Children with additional disabilities to their
  hearing loss may present extra challenges to the
  clinical team
• assessment of abilities
• (re)habilitation
• defining a successful outcome

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Aim

• Assess clinical protocols and policies following
  review of past experiences and available reports.
• Preliminary review of cases from Melbourne
  Cochlear Implant Clinic.

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Demographics
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Demographics (cont.)
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Speech perception categories (Dowell, R)

• 1. Detection only
• 2. Discrimination of suprasegmentals 1.
• 3. Recognition of vowels 2.
• 4. Recognition of consonants 3.
• 5. Minimal open-set speech recognition 4.
• 6. gt20 open-set speech recognition 5.
• 7. gt50 open-set speech recognition 6.

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Speech perception results
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Summary

• Wide range of speech perception abilities.
• 6 out of the 9 children can at least recognize
  vowels and consonants.
• 2 of the 4 children with an intellectual
  disability have gt20 speech recognition ability -
  both had progressive loss of hearing.

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Conclusion

• While children with multiple disabilities may
  require extra time and effort to assess their
  abilities and potential, cochlear implantation
  can offer improvements in speech perception and
  quality of life.