Candidacy for cochlear implant in infants and children Hedayat El-Fouly

• Cochlear implant candidacy criteria have evolved dramatically since multichannel implants were first approved for adult use by the FDA in 1985 and in 1990 for the pediatric population.

To determine the selection criteria for cochlear implantation. • Selection of patients depends on medical evaluation, audiometric data, speech discrimination, communication skills, cognitive skills, and psychosocial factors. • Computed tomography, magnetic resonance imaging, and electrophysiologic tests. • Side of implantation is chosen according to cochlear structure, duration of deafness, and dominant handedness. • A case-to-case decision has to be made based on additional diagnostics and the experience of the implant centre.

• The selection of children for cochlear implantation require close collaboration between the pediatric surgical team, the educational team, and the family. • It is accomplished via the collective teamwork of a multidisciplinary group of professionals, including audiologists, speechlanguage pathologists, deaf educators, social workers, radiologists, and of course, otologists and neurotologists.

• Due to the increasing experience, the improvement of implant technology and the proven reliability, the selection criteria are broadened with shifting borders. • The main extensions are related to age, additional handicaps, residual hearing and special etiologies of deafness.

• We are now implanting individuals with considerably more residual hearing, higher preoperative speech perception scores, and shorter durations of severe- to-profound deafness. • However, the basis for success still remains good rehabilitation, a team approach and the willingness of the patient to undergo the whole process of cochlear implantation.

• For children, the issue of auditory plasticity is of the essence. • Increasing evidence shows that very early implantation results in better performance and better hearing and speech development. • Cochlear implants have proven to be effective and reliable in congenitally deaf and perilingually deaf children up to the age of six years. • Children who received a cochlear implant followed by intensive therapy, are better able to hear, comprehend sound and music, and speak than their peers who receive implants when they are older.

• Children who receive a cochlear implant at a young age develop language skills at a rate comparable to children with normal hearing, and many succeed in mainstream classrooms. • In terms of speech development and language acquisition , nearnormal language acquisition can be achieved in children implanted under the age of two years. • For young children who are deaf or severely hard-of-hearing, implantation while young exposes them to sounds during an optimal period to develop speech and language skills.

• Severely hearing impaired patients may also be considered for cochlear implantation if their residual hearing provides no benefit for speech discrimination. The same holds true for children. • This development may continue and the borderline between hearing aids and cochlear implants will shift further towards severe hearing loss.

• Aside from audiometric threshold, perhaps the more definitive component of determining adult implant candidacy involves speech recognition testing. • As many of us recognize, individuals with significant hearing loss often report that they are unable to adequately “hear” someone unless they are looking directly at them. • Thus, they are relying heavily—if not entirely—on visual cues such as lip reading and nonverbal signals for communication.

• In determining cochlear implant candidacy, in order to gain an understanding of an individual's auditory-based speech recognition abilities, speech materials are presented without visual cues. • Just as important as presenting speech stimuli without visual cues is the presentation of recorded materials for the assessment of speech recognition abilities. • Historically, stimuli were presented at 70 dB SPL in the sound field (not representative of average conversational speech). • Average conversational speech levels were 60 dB SPL.

• Since 2000, cochlear implants have been FDA-approved for use in eligible children beginning at 12 months of age. • All CI devices can be safely indicated for children 12 months or older . • However, implanting children younger than 12 months remains controversial.

• Further reductions in age at implantation are currently limited by the nature of audiologic testing in very young children. • In cases of HL due to meningitis or hereditary hearing loss , implantation should be considered before the age of 12 months.

• For children aged 12-23 months hearing threshold for both ears should equal or exceed 90 dB. • For individuals older than 24 months hearing threshold should equal or exceed 70 dB. • Speech detection with best fit hearing aids in a sound field equal to or worse than 55 dB.

• Hearing aid trial for 3 months. • During HA trial , child should be making at least month to month auditory progress as well as speech and language progress. If this is not the case then, CI evaluation should be considered ( Gifford, H 2011 ).

• In other words, if a child has been fitted with hearing aids for 3 months, they should make at least 3 months of progress in auditory skills and speech/language development. • If this is not the case for a child making full-time use of amplification and appropriate intervention, then a cochlear implant evaluation should be considered.

Criteria for pediatric cochlear implantation include: 1- 12 months of age or older 2- Severe-to-profound sensorineural hearing loss in both ears 3- Inability to benefit from a hearing aid or other prosthetic device for communication. 4- Parents and/or families of patients must demonstrate a clear motivation to function (or have their child function) within a general community that depends on spoken communication

Criteria for pediatric cochlear implantation include: 5- Must be enrolled in an educational program that emphasizes development of auditory and verbal skills 6- Patients must not have a medical condition that places them at high risk for surgery 7- Parents and families must be committed to attending regularly scheduled training, mapping and follow-up sessions following implantation 8- No medical contraindications.

Children: aged 2-17 years • • • •

Severe to profound loss bilaterally Little or no benefit amplification Lack of progress in the development of auditory skills High motivation and realistic expectations regarding benefit from the child and parents

Very young children: • Profound sensorineural hearing loss bilaterally (It is important to note that this indication does not imply that children with less severe hearing loss do not benefit from cochlear implants). • Lack of progress in development of auditory skills with hearing aid(s) or other amplification. • High motivation and realistic expectations from family. • Other medical conditions, if present, do not interfere with cochlear implant procedure.

Special Etiologies • Meningitis:  9% of childhood deafness.  Labyrinthitis ossificans.  Implantation before 12 months of age. • Trauma:  Bilateral otic capsule fractures are uncommon.  Intraluminal fibrosis or ossification may occur which makes electrode insertion difficult.

Special Etiologies • Hyperbilirubinemia  Risk of auditory neuropathy. • Auditory neuropathy /dyssynchrony:  Many clinicians have been conservative about the outcome.  Sydney CIC has the most experience.  They reported variable outcome due to wide variability of impairments.

Special Etiologies • Cochlear implantation in obliterated cochleae and inner ear malformation requires a special surgical technique and special electrode arrays. • In this way even difficult cases can be managed with remarkable outcome.

Multi handicapped • Patients with additional disabilities such as mild motor disability, cerebral palsy , cognitive disabilities, specific learning disabilities, behavioral disorders and sight impairment have been implanted. • Multi-handicapped children receive benefit from cochlear implantation. The rate of this improvement is slow but offers better quality of life due to better auditory-communication skills, better self-independence and social integration.

Bilateral Cochlear Implants • It has been established that bilateral cochlear implants (CIs) offer additional speech perception and localization benefits to many children with severe to profound hearing loss. • These improved perceptual abilities facilitate significantly better language development has not yet been clearly established. • In some cases, physicians may recommend bilateral cochlear implants. At this time, not all insurers cover bilateral cochlear implants.

Bilateral Cochlear Implants • Bilateral CI use was found to predict significantly faster rates of vocabulary and language development than unilateral CI use; the magnitude of this effect was moderated by child age at activation of the bilateral CI.

Bilateral Cochlear Implants • Bilateral CIs offer additional benefits over a unilateral CI through the mechanisms of binaural redundancy (speech perception is improved with 2 ears, as the brain has 2 opportunities to process the signal), binaural summation (the signal when combined from 2 ears is slightly louder than from 1 ear), and the head-shadow effect (the head acts as a physical barrier to the sound, such that the signal will be softer at the ear that is farthest from the sound source).

Bilateral Cochlear Implants • Recent Trend towards BILATERAL use of CI/s -- 1992: 0-1% -- 2007: 14-15% • 70% of bilateral CI usage is among 18 years and under age group. • Simultaneous CI • Sequential CI

Bilateral Cochlear Implants 1. Implant both ears early during development, but risk loss of opportunity for at least some of the technology that is likely to be available during a child’s lifetime. 2. Implant one ear early, and “save” the second ear for future technology, but risk the potential loss of fidelity with which the auditory system can be bilaterally activated following a prolonged period of deprivation. 3. If one ear has residual hearing and amplification might offer benefits, care should be taken to assess the extent of those benefits prior to embarking on implantation of both ears.

Advantages of bilateral implantation • Improved hearing in quiet (binaural summation) • Improved hearing in noise (binaural squelch, head shadow effect, and binaural redundancy) • Improved sound lateralization • Improved sound localization • Assurance that the “better hearing ear” is implanted/”captured” • Qualitative listening improvement (more “balanced”; “richer quality”; more “confident” feeling; and less fatigued)

Disadvantages • • • • • •

Increased costs (2 devices, batteries, etc.) Multiple pieces of equipment to manage Surgical and medical risks Future developments No or limited “natural” hearing remaining Different processing strategies & speech processors (with sequential bilateral CIs)

Conclusion • Overall the selection criteria have been broadened with increasing experience and technological improvement. • This development may continue and the borderline between HA & CI will shift further. • For young children who are deaf or severely hard-of-hearing, implantation while young exposes them to sounds during an optimal period to develop speech and language skills.

Conclusion • Additional handicaps, special etiologies, and residual hearing do not automatically exclude a candidate from cochlear implantation. • However, the basis for success still remains good rehabilitation, a team approach and the willingness of the patient to undergo the whole process of CI.