Furthermore, the authors report, “A shorter interval between the first and the second cochlear implant, and consequently more experience with the second cochlear implant, had a positive effect on the language results.”
Tinne Boons, at the Katholieke Universiteit Leuven, Belgium, and colleagues hypothesized that the greater level of level of language immersion provided by bilateral cochlear implantation would improve the development of language skills in these children.
To test this, they measured comprehension and expression of spoken language in 25 children with one cochlear implant and in 25 closely matched children with two implants, selected from a retrospective cohort of 288 patients seen at two Belgian and three Dutch cochlear implantation centers.
All the children received their implants before age 2.06 years, none had multiple other disabilities, and all had monolingual parents with normal hearing, the report indicates. They were also matched on sex and cause of deafness.
On the Reynell Developmental Language Scales (RDLS) used to measure age-appropriate language comprehension level, the mean score was 85.6 in the bilateral group versus 76.2 in the unilateral group (p=0.04), the researchers found.
Similarly, for expressive language, the corresponding mean scores for word development on a standardized test were 86.1 versus 70.4 (p<0.001), respectively, and 86.8 versus 77.0 (p=0.01) for sentence development, the team reports.
As noted, the interval between bilateral implants influenced language performance. In fact, children who underwent simultaneous implantation had better word development scores than those who had sequential dual implants, Ms Boons and colleagues report.
In concluding, they note, “Although several studies have shown the positive effect of bilateral implantation in children on auditory development, our study is one of the first, to our knowledge, to demonstrate a positive effect on language test scores.”
They add, “Results from this study carry implications for the clinical treatment of deaf children receiving cochlear implants.”
The authors of a related editorial concur. “Advocates of children are encouraged to support early implantation of implants in deaf children and the opportunity to undergo binaural implantation regardless of socioeconomic circumstances,” they state.
Arch Pediatr Adolesc Med 2012;166:28-34.