Early vocabulary development in children with bilateral cochlear implants

Abstract

Background: Children with unilateral cochlear implants (CIs) may have delayed vocabulary development for an extended period after implantation. Bilateral cochlear implantation is reported to be associated with improved sound localization and enhanced speech perception in noise. This study proposed that bilateral implantation might also promote early vocabulary development. Knowledge regarding vocabulary growth and composition in children with bilateral CIs and factors associated with it may lead to improvements in the content of early speech and language intervention and family counselling. Aims: To analyse the growth of early vocabulary and its composition during the first year after CI activation and to investigate factors associated with vocabulary growth. Methods & Procedures:The participants were 20 children with bilateral CIs (12 boys; eight girls; mean age at CI activation = 12.9 months). Vocabulary size was assessed with the Finnish version of the MacArthur Communicative Development Inventories (CDI) Infant Form and compared with normative data. Vocabulary composition was analysed in relation to vocabulary size. Growth curve modelling was implemented using a linear mixed model to analyse the effects of the following variables on early vocabulary growth: time, gender, maternal education, residual hearing with hearing aids, age at first hearing aid fitting and age at CI activation. Outcomes & Results: Despite clear vocabulary growth over time, children with bilateral CIs lagged behind their age norms in receptive vocabulary during the first 12 months after CI activation. In expressive vocabulary, 35% of the children were able to catch up with their age norms, but 55% of the children lagged behind them. In receptive and expressive vocabularies of 1-20 words, analysis of different semantic categories indicated that social terms constituted the highest proportion. Nouns constituted the highest proportion in vocabularies of 101-400 words. The proportion of verbs remained below 20% and the proportion of function words and adjectives remained below 10% in the vocabularies of 1-400 words. There was a significant main effect of time, gender, maternal education and residual hearing with hearing aids before implantation on early receptive vocabulary growth. Time and residual hearing with hearing aids had a significant main effect also on expressive vocabulary growth. Conclusions & Implications: Vocabulary development of children with bilateral CIs may be delayed. Thus, early vocabulary development needs to be assessed carefully in order to provide children and families with timely and targeted early intervention for vocabulary acquisition.

Morphosyntactic abilities of toddlers with hearing impairment and normal hearing: evidence from a sentence‐repetition task

“…Some children with HI are reported to show age-appropriate levels of lexical knowledge, while others do not reach norms of children with NH. For example, group findings show that only one-third of the children perform similarly to their NH peers (e.g., Rinaldi et al 2013, Välimaa et al 2018. Interestingly, Tomblin et al (2005) showed that expressive skills of English-speaking children with HI were within the range expected for children with NH; however, the performance of children with HI showed a downward trend over a period of 24 months.…”

Acoustic features of infant-directed speech to infants with hearing loss

“…To date, no previous studies have compared the properties of IDS to these two groups. However, this finding is not entirely surprising when viewed in the context of research showing that infants with unilateral HL have delayed vocabulary development and poorer auditory and language outcomes in comparison to infants with bilateral HL (Fitzpatrick et al, 2019;Välimaa et al, 2018).…”

“…Second, infants' auditory perception varies depending on whether their HL is bilateral or unilateral. For instance, infants with unilateral HL have delayed vocabulary development compared to infants with bilateral HL (Fitzpatrick et al, 2019;Välimaa et al, 2018), and infants with bilateral HL show better sound localisation acuity and speech perception in noise (Johnston, Durieux-Smith, Angus, O'Connor, & Fitzpatrick, 2009) and develop higher receptive and expressive vocabulary skills compared to infants with unilateral HL (Boons et al, 2012;Sarant, Harris, Bennet, & Bant, 2014). While no studies to date have investigated the effects of bilateral vs. unilateral HL configuration on IDS components, differences in IDS qualities to these infants could be expected given the factors described above as well as other experiential factors such as different intervention approaches for infants with unilateral and bilateral HL, later age of fitting for infants with unilateral HL (Fitzpatrick, Whittingham, & Durieux-Smith, 2014), and greater confusion among parents of infants with unilateral HL regarding effectiveness of intervention practices (Fitzpatrick et al, 2015).…”

Discrimination and identification of lexical tones and consonants in Mandarin-speaking children using cochlear implants

“…exhibited lower vocabulary scores than their peers with NH, suggesting that auditory deprivation in early ages had impeded language acquisition (Lund, 2015;Välimaa et al, 2018). Moreover, there is a general trend that the performance variability of the CI group for discrimination and identification of speech sounds is greater (as shown in Figures 1 and 2) than that of the NH group, showing that Mandarin-speaking children with similar severity of hearing loss before CI implantation do not perceive consonants and lexical tones in similar ways after CI implantation.…”