University of Edinburgh

Cochlear Implant Update

Presented on Thursday, 12 May 2011

Agnes Allen, Scientific Head of Service/Consultant Clinical Physicist

Cochlear implant users 2011

There are ~ 250,000 cochlear implant users in the world.

  • ~10,000 are within the UK
  • anticipate ~1000 in Scotland?

~ 860 cochlear implant users in Scotland

  • ~85 under 5s
  • ~155 primary school
  • ~100 secondary school
  • ~300 19–60 year-olds
  • ~220 over 60s
  • Approximately 130 bilateral CI users

Scottish Cochlear Implant Programme for Adults & Children, Crosshouse Hospital, Kilmarnock

crosshouse hospital

Multidisciplinary Team

  • Audiologists
  • Clinical Physicists
  • ENT Surgeons
  • Rehabilitation Specialists
  • Support Staff

Cochlear Implant

  • Sensory aid
  • For those with a bilateral profound hearing loss who receive little or no benefit from conventional hearing aids
  • Provide access to spoken language through hearing

Puretone thresholds

puretone thresholds

Electrode array


electrode array

Selection Criteria

  • Bilateral Severe-to-Profound Hearing Loss
  • Limited benefit from hearing aids
  • Fit enough to undergo GA/surgery
  • Able to participate in programming sessions
  • Ability to process auditory information from Cochlear Implant
  • No upper age limit for children who present with functional spoken language
  • Upper age limit of 5 years old for children who present with little or no spoken language

Cochlear Implant

cochlear implant

  • 2 to 3 hour Surgical procedure
  • In hospital for 2 to 3 days
  • Passive device
  • Designed to last a lifetime

Speech Processor

  • Active device
  • Externally worn
  • Removable
  • Needs to be programmed, maintained & replaced

speech processor

Initial fitting

  • 4 weeks post-surgery – 'switch-on'
  • External Equipment Issued
  • Electrodes activated for the first time
  • Mode of Stimulation, Stimulus Levels etc.
  • Speech coding strategy (SPEAK, ACE etc.)

Regular follow-up Life-long support

Early intervention is crucial for spoken language development in deaf children

  • Auditory deprivation has a detrimental effect on the development of central
    auditory pathways.
  • Auditory stimulation is required for pathways/language centres to form.
  • This happens within a critical time period (neuroplasticity).
  • Generally believed to be 5 years old.

The 'Hearing Brain'

the hearing brain

Cochlear implantation can enable profoundly deaf children to:

  • Acquire and understand spoken language, speak intelligibly and use the telephone
  • Have improved literacy and educational attainments
  • Attend mainstream school

Do cochlear implants work equally well for everyone?

All cochlear implant users have exactly the same audiogram

  • It is flat across the full frequency range
  • Hearing thresholds are equivalent to a mild hearing loss
  • Hearing does not deteriorate

Factors influencing outcome

  • Hearing history
  • Age at time of implant
  • Home environment
  • Device use
  • Communication approach
  • Co-existing morbidity

Outcomes in children

The earlier children are implanted, the better the outcomes; provided that they wear the CI device all day/every day and immersed in spoken language.