Bilateral Versus Unilateral Cochlear Implants in Children

Abstract

Objectives:Although it has been established that bilateral cochlear implants (CIs) offer additional speech perception and localization benefits to many children with severe to profound hearing loss, whether these improved perceptual abilities facilitate significantly better language development has not yet been clearly established. The aims of this study were to compare language abilities of children having unilateral and bilateral CIs to quantify the rate of any improvement in language attributable to bilateral CIs and to document other predictors of language development in children with CIs.Design:The receptive vocabulary and language development of 91 children was assessed when they were aged either 5 or 8 years old by using the Peabody Picture Vocabulary Test (fourth edition), and either the Preschool Language Scales (fourth edition) or the Clinical Evaluation of Language Fundamentals (fourth edition), respectively. Cognitive ability, parent involvement in children’s intervention or education programs, and family reading habits were also evaluated. Language outcomes were examined by using linear regression analyses. The influence of elements of parenting style, child characteristics, and family background as predictors of outcomes were examined.Results:Children using bilateral CIs achieved significantly better vocabulary outcomes and significantly higher scores on the Core and Expressive Language subscales of the Clinical Evaluation of Language Fundamentals (fourth edition) than did comparable children with unilateral CIs. Scores on the Preschool Language Scales (fourth edition) did not differ significantly between children with unilateral and bilateral CIs. Bilateral CI use was found to predict significantly faster rates of vocabulary and language development than unilateral CI use; the magnitude of this effect was moderated by child age at activation of the bilateral CI. In terms of parenting style, high levels of parental involvement, low amounts of screen time, and more time spent by adults reading to children facilitated significantly better vocabulary and language outcomes. In terms of child characteristics, higher cognitive ability and female sex were predictive of significantly better language outcomes. When family background factors were examined, having tertiary-educated primary caregivers and a family history of hearing loss were significantly predictive of better outcomes. Birth order was also found to have a significant negative effect on both vocabulary and language outcomes, with each older sibling predicting a 5 to 10% decrease in scores.Conclusions:Children with bilateral CIs achieved significantly better vocabulary outcomes, and 8-year-old children with bilateral CIs had significantly better language outcomes than did children with unilateral CIs. These improvements were moderated by children’s ages at both first and second CIs. The outcomes were also significantly predicted by a number of factors related to parenting, child characteristics, and family background. Fifty-one percent of the va...

Development of Grammatical Accuracy in English-Speaking Children With Cochlear Implants: A Longitudinal Study

“…However, the advantage of bilateral CIs over unilateral CIs on speech and language acquisition remains unclear, given mixed findings from different studies. For example, whereas Sarant, Harris, Bennet, and Bant (2014) found a bilateral advantage for language acquisition, Nittrouer and Chapman (2009) did not. In a recent study, Nittrouer et al (2014) further found that children with unilateral and bilateral CIs did not differ significantly in the use of grammatical morphemes.…”

Predictors of pediatric cochlear implantation outcomes in South Africa

“…[70] also used the CAP as outcome measure in a group of 35 children with bilateral CIs, showing that after three years of bilateral implant use, higher CAP scores were obtained for significantly more children than before their second implant. Although the positive effect of bilateral implantation on spoken language development has recently been demonstrated [45,53], the influence of bilateral implantation on speech production remains to be demonstrated [48].…”

“…The benefits of bilateral implantation in children are well documented in terms of improved localization [46][47][48] and enhanced speech recognition in quiet [49,50] and in noise [46,51,52] when compared to listening with a unilateral CI. Also recently confirmed, children with bilateral CIs have significantly better language outcomes compared to children with unilateral CIs [45,53]. However, there is still a lack of evidence regarding the effect of bilateral cochlear implantation on broader outcomes such as literacy, academic skills and overall quality of life, particularly concerning long-term outcomes [45,48,54].…”

“…Also recently confirmed, children with bilateral CIs have significantly better language outcomes compared to children with unilateral CIs [45,53]. However, there is still a lack of evidence regarding the effect of bilateral cochlear implantation on broader outcomes such as literacy, academic skills and overall quality of life, particularly concerning long-term outcomes [45,48,54].…”

“…In recent years there has been increasing interest in outcomes of bilateral cochlear implantation, since it has become the standard of care for children with severe to profound hearing loss in developed countries [14,45]. The benefits of bilateral implantation in children are well documented in terms of improved localization [46][47][48] and enhanced speech recognition in quiet [49,50] and in noise [46,51,52] when compared to listening with a unilateral CI.…”