A Longitudinal Study on Auditory Perception and Speech Intelligibility in Deaf Children Implanted Younger Than 18 Months in Comparison to Those Implanted at Later Ages

Objective: The objective of this study was to measure longitudinally the progress in the auditory performance and speech intelligibility of young deaf children implanted under the age of 18 months in comparison to those implanted after 18 months and to create normative data on these children implanted under 18 months. Study Design: This is a retrospective longitudinal study based on data available at our centre 'KIDS-Hasselt-Belgium'. Patients: 52 deaf children who received a cochlear implant under the age of 18 months. Methods: LiP (Listening Progress profile) and CAP (Categories of Auditory Performance) were administered to measure auditory perception and SIR (Speech Intelligibility Rating) was used to measure speech intelligibility. Over a 4 year period, six assessments were made to monitor the auditory and speech development of the children: a pre-test before implantation and five post-tests at 6, 12, 24, 36 and 48 months after implantation. Results: Deaf children receiving cochlear implants before the age of 18 months show more rapid progress in auditory performance and speech intelligibility in comparison to children implanted at an older age. Their auditory performance and speech intelligibility also reach a higher level 4 years after implantation compared with children implanted later in life. Discussion and Conclusion: This study shows encouraging results in the cochlear implantation of children under the age of 18 months. As demonstrated, using the LiP, CAP and SIR measures, children who receive a cochlear implant before the age of 18 months show, that at 3 to 4 years after implantation, significantly greater improvement is made in auditory perception and speech intelligibility than their later implanted peers, although there is a considerable variety in the outcomes.