BATOD recognises that some ToDs use the term 'hearing-impaired' synonymously with deaf.

Cochlear implants in children: past, present and future?

Sue Archbold, Education Co-ordinator, The Ear Foundation

Apart from the changes in numbers, the procedures and criteria have changed over the years. Initially only those children with near total hearing losses were implanted; now children with some residual hearing are receiving implants. Children with aided thresholds of 50dB and even less, will routinely be considered for implantation; through their implant they are likely to receive sound in the region of 30dB across the speech frequencies, receiving useful high frequency information. Many children successfully have an implant in one ear and wear a hearing aid in the other. In some countries bilateral implantation is becoming the norm, giving benefits of localisation and of listening in noise.

In addition to children with some residual hearing being considered for implantation, the age of those implanted has also changed. Following an earlier diagnosis of hearing loss, children are being referred earlier for implantation and being implanted earlier. Currently, the youngest child to be implanted in the UK was an infant of six months. On the other hand, increasing numbers of teenagers are requesting implants for themselves; these are likely to be those who are using their residual hearing well and use spoken language but who would receive more of the speech signal through an implant. Increasing numbers of children with complex needs are also receiving implants. This requires a great deal of careful assessment, particularly to ensure that there is a definitive assessment of the levels of hearing. Up to 40% of deaf children are likely to have another difficulty and one which an implant may not help. Interestingly, more deaf children of deaf parents are now receiving implants - in order to give them both spoken and sign language.

The procedure of implantation itself has now changed – the stay in hospital is likely to be one day and there will be minimal hair shave (if any) and a small scar behind the ear. The technology has changed over the years, enabling tuning of the external system to take place more easily with objective measures taken. In addition the external systems are smaller with ear level processors much more commonly used.

Cochlear implantation has been shown to be safe and devices largely reliable. In a series of 500 operations over 15 years on children at the Nottingham Cochlear Implant Programme, there have been 18 failed devices, all successfully replaced, three cases of infection and three devices removed for other reasons. In the same group of children, the usage rate remains high, with over 90% of children continuing to choose to wear their implant systems all or most of the time, five years after implantation.

Although results from implantation can be very variable, we do know that age at implantation has a strong effect on outcomes. If we look at changes in a child’s ability to use hearing to understand spoken language, five years after implantation, over 80% of children implanted under three can understand conversation without lipreading. If we look at speech intelligibility, we see a similar pattern, with 40% of children implanted below the age of three having speech with normal intelligibility, five years after implantation.

What have been the changes we have seen educationally? With regard to educational placement of children with implants, significantly more children implanted before the age of five go to mainstream schools and significantly fewer to schools for the deaf, when compared with a like group of children with hearing aids. When we look at communication and use of spoken language, we can see changes after implantation over time. In a study looking at the effect of communication mode on progress after implantation, those children using oral language at three years after implantation outscored those using sign language. However, when those who had always used oral language were compared with those who began using sign language and had changed to oral language after three years, there was no significant difference between them. A current research study, funded by NDCS, is looking at the pattern of changes in communication after implantation. Although the aim of cochlear implantation is to provide hearing for speech, for some children sign language has a role and the issue of cochlear implantation and sign language clearly needs investigation. The large UK study led by Quentin Summerfield, formerly of IHR and in which many Teachers of the Deaf participated, has shown an effect of cochlear implantation on educational attainments: children with implants are performing as children who are less deaf.

With this growing experience of implantation, what are the major issues?

• access to high frequency hearing rare in a hearing aid user
• complexity of monitoring the device functioning
• complexity of device programming
• implementation of changes in technology over time
• management of device and technology difficulties
• length of time taken for progress – often years not months
• flexibility of educational support required: placement, levels of support and communication may change over time
• medical risks associated with implantation.

There are three other issues emerging as we gain more experience.

• It may be that implants sometimes work too well! Levels of intelligibility are sometimes such that it may appear to a non-specialist that the child has no difficulty in accessing the curriculum; this is a naïve view. These remain profoundly deaf children but function as less deaf than before implant.
• There are other children who do not do as well as one might have predicted. It is likely that these children have learning difficulties not identifiable prior to implantation, which now can be more readily identified when they have some useful hearing.
• Another recurring theme in discussion about implantation is the management of those with implants as they grow through adolescence and maintaining and developing implant use through these challenging times, supporting them in developing a secure identity as a deaf person with an implant.

In order to maximise the benefits of implantation, teachers need to know about:

• the differences between cochlear implants and hearing aids
• appropriate candidature
• expectations from implantation for different populations
• the fundamentals of an implant system
• the basics of the tuning process
• monitoring the system functioning and trouble-shooting
• monitoring the child’s progress.

These are some of the everyday knowledge and skills required; however, for them to be put in place and utilised effectively, there may need to be some organisational changes. Educational services need to look at how they:

• organise their services to provide effective, trained support in the classroom for those in mainstream
• provide placement and communication choices as children’s needs change
• meet the challenges of sign-bilingualism and bilingualism and cochlear implants
• provide appropriate education for those for whom an additional language difficulty may become apparent after implantation
• provide support for the implant system and the amount of hearing it provides in the demanding environment of secondary or high school
• implement changes in technology and support them throughout the child’s educational life
• provide for the psycho-social needs of the children as they grow to independence.

With growing numbers of children receiving implants at earlier ages, including those with complex needs, it is vital that teachers receive regular updates in the management of this rapidly changing technology. The developments are far from finished: bilateral implants, implants with electrical and acoustic stimulation, wholly implantable devices and those promoting hair cell regeneration are some of the technical developments which will be in use in our classrooms over the next ten years. At the Ear Foundation the education programme provides a bridge between the clinic-based services, home and school where the children actually use the technology.

As the Teacher of the Deaf of the first child to receive an implant, I find an entry in my diary from 1987: “will all this come to anything and be worth the effort?”

The outcomes we are seeing in many children are far beyond what we expected then, when we felt some deafened children may be able to hear environmental sounds and perhaps have an aid to lipreading. Who knows what the next ten years will bring?

March 2005