The characteristics of prelexical babbling after cochlear implantation between 5 and 20 months of age.

OBJECTIVES

To compare the characteristics of prelexical babbling of 10 deaf children, who received a cochlear implant (CI) between 5 and 20 mo of age with that of hearing children.

DESIGN

Prospective controlled longitudinal trial comparing 10 congenitally deaf children of hearing parents, who received a multichannel Nucleus-24 CI in their first or second year of life with 10 normal-hearing (NH) children. During the entire babbling period, monthly video samples of 20 min were selected and transcribed. The characteristics of babbling were investigated at three levels: (1) segmentally by means of inventories of consonant (C) and vowel (V) types, (2) intrasyllabically by assessing preferred consonant-vowel (CV) combinations, and (3) intersyllabically by assessing reduplication and variegation of successive CV syllables.

RESULTS

(1) Segmental analysis - no statistical difference: both groups preferred to produce coronals and labials with regard to C place, and stops and glides with regard to C manner. Mid-front and mid-central vowels were the predominant V types in both groups. (2) Intrasyllabic analysis - no statistical difference: both groups preferred to combine coronal Cs with front vowels (Vs) and labial Cs with back Vs, and disliked coronal-back and labial-front CV combinations. These four significant CV combinations, however, emerged earlier in the babbling period of NH group than that of CI children. (3) Intersyllabic analysis: in comparison with the NH group, the CI children used significantly less variegated CVCV and in case of variegation, the proportion of combined C + V variegations was significantly lower. In case of C variegations, complex C variegations (manner + place) occurred considerably less frequently in the babbling of the CI children in comparison with that of the NH children (although this difference was not statistically significant).

CONCLUSIONS

This study shows that the qualitative babbling characteristics of early implanted CI children are very similar to those of hearing children from the onset of babbling onward. Only when combining CV syllables into CVCV utterances, CI children prefer simplicity to complexity in comparison with hearing children.