Advantages of cochlear implantation in prelingual deaf children before 2 years of age when compared with later implantation.

OBJECTIVES: To compare the auditory abilities and speech performance of children with a profound prelingual bilateral hearing-impairment when subjected to a cochlear implant (CI) before or after 2 years of age. To analyze the complications that arose during, or as a result of, the implantation process in these groups. DESIGN: Prospective cohort single-subject, repeated-measures study of children with profound bilateral hearing impairment subjected to CI. SETTING: Tertiary referral center with a program of pediatric CI from 1991. PATIENTS: This study analyzed 130 children subjected to multichannel CI for profound prelingual bilateral hearing-impairment in two age groups: 0 to 2 (n = 36) and 2 to 6 years of age (n = 94). INTERVENTIONS: The children were evaluated before, and each year after, the intervention (for up to 5 years) with both closed-set and open-set auditory and speech perception tests. Their speech ability was evaluated according to the Peabody Picture Vocabulary and Reynell general oral expression scales. RESULTS: Auditory and speech perception tests improved significantly in all children after CI, regardless of the follow-up time. The infant's performance was better the earlier the implant was performed. Speech tests showed that the development of children treated before 2 years of age was similar to normal children, and no additional complications were observed when compared with CI in older children. CONCLUSIONS: When performed before 2 years of age, CI offers a quicker and better improvement of performance without augmenting the complications associated with such an intervention.

Prospective long-term auditory results of cochlear implantation in prelinguistically deafened children: the importance of early implantation.

The objectives of this study were to report the long-term auditory results of prelinguistically deafened children with bilateral profound hearing impairment treated with a cochlear implant (CI); to analyze the role of auditory stimulation in the development of communicating abilities in early implanted children; and to define the limits of the auditory critical period. It was designed as a prospective cohort single-subject repeated-measures study of children with bilateral profound hearing impairment treated with a CI at a tertiary referral center with a pediatric CI program since 1991. A total of 182 children with bilateral prelinguistic hearing impairment of profound degree treated with a Nucleus CI were enrolled in the study. Eighty-six children received a Nucleus 22 CI and 74 received a Nucleus 24. For data analyses the children were categorized by ages: 0-3 years of age (n = 94); 4-6 years (n = 36); 7-10 years (n = 30); 11-14 years (n = 22). The children were evaluated with a protocol that included tests of audition and speech perception, with closed-set (Vowel Confusion test, Series of Daily Words) and open-set tests (e.g. bisyllables, CID Sentences, CID Sentences adapted for children). Pure-tone averages significantly improved for all children in all groups with the CI compared with preoperative values. Nevertheless, only children implanted before the age of 6 years developed a high ability for recognition of bisyllables and sentences in an open-set. Results show that the earlier the implantation is undertaken, the better the performance outcome. Children implanted outside of the auditory critical period demonstrated significantly poorer performance, suggesting the occurrence of irreversible changes in the central auditory system. In conclusion, eligible children should receive a CI as soon as bilateral profound hearing impairment is diagnosed. This usually permits them to achieve high-performance levels on speech and language measures and potentially integration into an oral communication environment.