Conclusions: Formal testing showed that HiRes users seem to make significant use of acoustic information. Furthermore, from observations reported by experienced care-givers, for example, family, teachers and speech therapists, these children learn a lot from their surrounding environment. Incidental learning, which takes place when acquiring skills or knowledge through naturally occurring events, is a key become available to these deaf paediatric cochlear implant recipients.
Objective: To compare speech perception skills in children with a Clarion cochlear implant using different speech coding strategies, such as continuous interleaved sampling (CIS), simultaneous analogue stimulation (SAS) and Hi-Resolution (HiRes).
Material and methods: The study population comprised 40 children, 17 implanted with a Clarion Hi-Focus 1.2 and 23 with a Clarion CII. All children were pre-lingually deaf and differed in terms of age and cause of deafness. All children had undergone a trial (minimum 6 months) with hearing aids before implantation. Children implanted with a Clarion 1.2 were either CIS or SAS users [Standard Resolution mode (SRM) group]; children implanted with a Clarion CII were Hi-Resolution users [Hi-Resolution mode (HRM) group]. Findings were assessed according to-Erber's hierarchical model (detection, discrimination, identification, recognition and comprehension), making use of a battery of speech perception tests calibrated to the age of the child. Further information concerning use of the implant in everyday situations was obtained by means of the Meaningful Auditory Integration Scale (MAIS) questionnaire, which was administered to the parents. Tests were carried out prior to each fitting session, at switch-on and then at 3, 6, 9 and 12 months. Findings at pre-implantation and at 12 months follow-up were collected for both the SRM and HRM groups. Speech perception results were analysed for the SRM and HRM groups, independent of age at implantation, for five subgroups of children according to the paediatric test battery in use and for two subgroups of children, one < and one > 5 years of age.
Results: Clarion-implanted children using the Hi-Resolution strategy can develop better speech perception skills at 12 months post-implantation compared to children fitted with the SAS or CIS strategy. SAS or CIS users implanted before the age of 5 years tend to achieve better results at 1 year follow-up than children implanted later. In contrast, in Hi-Resolution users, a trend towards better results for recognition and comprehension tasks was observed in children implanted after 5 years of age.