Outcomes of Children with Cochlear Implant-Assisted Hearing and Autism Spectrum Disorder

Background: Cochlear implant clinics now select paediatric candidates solely on audiology criteria, predominantly that hearing aids cannot provide adequate amplification for speech and language development. Previously candidates were excluded because of disability, and particularly of Autism diagnosis, in the belief that children would not benefit from cochlear implantation. Limited literature published has presented negative outcomes of implanted children with Autism. Our study is the largest and first to examine outcomes with regard to cognitive ability.   

Objectives: To examine communication and educational outcomes of implanted children with severe-profound hearing loss and Autism Spectrum Disorder in the context of cognitive ability.  

Methods: Progressive longitudinal follow-up of 31 children implanted in the Royal Victorian Eye and Ear Hospital programme 1999-2012. Children were diagnosed using DSM-IV criteria, generally by a psychologist specializing in hearing impairment and Autism diagnosis using the ADOS and ADI-R.  Diagnosis was confirmed by paediatrician and speech pathologist. All children had MRI and CT brain scans, with aetiologies of hearing loss recorded.  Tests of non-verbal cognitive ability and of expressive and receptive language were chosen according to ages and abilities, most commonly Wechsler or Griffiths Scales, and the Preschool Language Scale. Children were included in the study once communication follow-up (‘hearing age’) was three or more years post-implant.   

Results: Twenty-five children had communication assessments three-plus years post-implant. Mean age of diagnosis of hearing impairment was 9.9 months (SD 9.0), and Autism 49.5 months (SD 20.7). Fourteen children had Normal cognitive ability (IQ 70 plus), and 11 had cognitive Disability (IQ below 70).  There were no significant differences (.05 level) between Normal and Disability groups in mean age of diagnosis of hearing impairment, aiding, or implantation, or in age at cognitive or language assessment. Mean ages in months were: aiding 11.7 (SD 8.9), cochlear implantation 32.9 (SD 25.9), cognitive assessment 53.9 (SD 26.4), and communication 'hearing age' assessment 57.9 (SD 23.5). All Normal and 4 Disability group children had normal MRIs.  Aetiologies were known in 21 children, with an acquired base (CMV or prematurity) in one Normal and 5 Disability group children, and the remainder genetic or structural. Seven Normal and no Disability group children had normal range oral communication results (standard score 70 plus), with significant group differences (receptive x² 7.6 1df p=.005, expressive x² 4.9 1df p=.02). Nine Normal group children were oral only, 4 used speech and Auslan sign, and 1 sign.  In the Disability group, no child was totally oral, and children used limited sign or PECS.  All children attended preschool intervention for hearing impairment; two Normal and 9 Disability group children attended centres for other disabilities. At school-age, 11 of 12 Normal and 3 of 8 Disability group children attended mainstream school with support, while the remaining 6 school-age children attended schools for children with disability. 

Conclusions: Implanted children with normal cognitive ability and Autism can acquire functional oral language as their sole communication mode.  Most attend supported mainstream school. Their outcomes are superior to those who also have cognitive disability.