An investigation of the first lexicon of Turkish hearing children and children with a cochlear implant

Vocabulary Growth in Mandarin-Speaking Children With Bilateral Cochlear Implants, Bimodal Stimulation, or Unilateral Cochlear Implants During the First Year After Activation

PURPOSE

The purpose of this study was to evaluate vocabulary development in Mandarin-speaking children with bilateral cochlear implants (CIs), bimodal stimulation (CI plus hearing aids [HAs]), or unilateral CIs during the first year after CI activation.

METHOD

Participants included 23 children with simultaneous bilateral CIs, 23 children with bimodal stimulation, and 15 children with unilateral CIs. They all received CIs before 30 months of age. Parents were asked to endorse words that their child could understand only or understand and say using the Early Vocabulary Inventory for Mandarin Chinese at the day of CI activation and 1, 3, 6, 9, and 12 months after CI activation. Receptive and expressive vocabulary sizes were computed.

RESULTS

Growth curve analysis revealed that children with simultaneous bilateral CIs demonstrated faster growth of receptive vocabulary than those with bimodal stimulation, followed by those with unilateral CIs. Moreover, children with simultaneous bilateral CIs reached the 100-word mark for receptive vocabulary earlier than children with bimodal stimulation, followed by those with unilateral CIs. There were no significant differences among the three groups in expressive vocabulary.

CONCLUSIONS

Bilateral CIs have an advantage over bimodal stimulation in early receptive vocabulary development in Mandarin, a tone language. HA usage is still recommended for those who receive one CI.

Semantic word integration in children with cochlear implants: Electrophysiological evidence

Differential auditory experiences of children with hearing-loss who receive cochlear implants (CIs) may influence the integration of lexical and conceptual information. Here we measured event-related potentials during a word-picture priming task in CI-using children (n = 29, mean age = 81 months) and typically-hearing children (n = 19, mean age = 75 months) while they viewed audiovisual-word primes and picture targets that were semantically congruent or incongruent. In both groups, semantic relatedness modulated ERP amplitude 300-500ms after picture onset, signifying an N400 semantic effect. Critically, the CI-using children's responses to unrelated pairs were significantly more negative than hearing children's responses. Group differences were mirrored in an earlier 150-275ms time window associated with a P2 response. The present findings suggest attentional and/or strategic differences impact semantic processing and contribute to the N400 differences observed between groups.

Early Vocabulary Profiles of Young Deaf Children Who Use Cochlear Implants

Purpose This study examined vocabulary profiles in young cochlear implant (CI) recipients and in children with normal hearing (NH) matched on receptive vocabulary size to improve our understanding of young CI recipients' acquisition of word categories (e.g., common nouns or closed-class words). Method We compared receptive and expressive vocabulary profiles between young CI recipients (n = 48; mean age at activation = 15.61 months, SD = 4.20) and children with NH (n = 48). The two groups were matched on receptive vocabulary size as measured by the MacArthur-Bates Communicative Development Inventories (Fenson et al., 2006): Words and Gestures form. The CI group had, on average, 8.98 months of hearing experience. The mean chronological age at completing the MacArthur-Bates Communicative Development Inventories was 23.99 months (SD = 5.14) for the CI group and 13.72 months (SD = 1.50) for the NH group. Results The CI group had a larger expressive vocabulary size than the receptive vocabulary size-matched NH group. The larger expressive vocabulary size was associated with the group difference in social words but not with common nouns. The analyses for predicate words and closed-class words included only children who produced the target categories. The CI group had a larger proportion of predicate words than the NH group, but no difference was found in closed-class words in expressive vocabulary. Conclusions Differences found in expressive vocabulary profiles may be affected by spoken vocabulary size and their age. A further examination is warranted using language samples to understand the effect of language input on children's vocabulary profiles.

Prelingual auditory-perceptual skills as indicators of initial oral language development in deaf children with cochlear implants

OBJECTIVES

To assess when prelingually deaf children with a cochlear implant (CI) achieve the First Milestone of Oral Language, to study the progression of their prelingual auditory skills in the first year after CI and to investigate a possible correlation between such skills and the timing of initial oral language development.

METHODS

The sample included 44 prelingually deaf children (23 M and 21 F) from the same tertiary care institution, who received unilateral or bilateral cochlear implants. Achievement of the First Milestone of Oral Language (FMOL) was defined as speech comprehension of at least 50 words and speech production of a minimum of 10 words, as established by administration of a validated Italian test for the assessment of initial language competence in infants. Prelingual auditory-perceptual skills were assessed over time by means of a test battery consisting of: the Infant Toddler Meaningful Integration Scale (IT-MAIS); the Infant Listening Progress Profile (ILiP) and the Categories of Auditory Performance (CAP).

RESULTS

On average, the 44 children received their CI at 24±9 months and experienced FMOL after 8±4 months of continuous CI use. The IT-MAIS, ILiP and CAP scores increased significantly over time, the greatest improvement occurring between baseline and six months of CI use. On multivariate regression analysis, age at diagnosis and age at CI did not appear to bear correlation with FMOL timing; instead, the only variables contributing to its variance were IT-MAIS and ILiP scores after six months of CI use, accounting for 43% and 55%, respectively.

CONCLUSION

Prelingual auditory skills of implanted children assessed via a test battery six months after CI treatment, can act as indicators of the timing of initial oral language development. Accordingly, the period from CI switch-on to six months can be considered as a window of opportunity for appropriate intervention in children failing to show the expected progression of their auditory skills and who would have higher risk of delayed oral language development.