Benefit of Bilateral Cochlear Implantation on Phonological Processing Skills in Deaf Children.

HYPOTHESIS: Children with bilateral cochlear implants (CIs) would have better phonological processing skills than children with unilateral CIs because those with bilateral CIs have better speech perception abilities in noisy environments and higher levels of central auditory system development than those with unilateral CIs.

BACKGROUND

Previous studies have focused on the performance of children with bilateral CIs on standardized clinical assessments. However, these tests are not sufficiently sensitive to explain better speech and language outcomes in children with bilateral CIs than children with unilateral CIs. Thus, this study focused on phonological processing skills at more central levels of analysis that reflect the operation of cognitive processes.

METHOD: Twenty children with bilateral CIs and 20 children with unilateral CIs, aged 4 to 6 years, participated in this study. The children completed the experience-dependent tasks and phonological processing tasks. The experience-dependent tasks involved the monosyllabic word, articulation, and receptive vocabulary tests. The phonological processing tasks involved the phonological awareness, phonological memory, and rapid automatic naming tasks. Task performance was compared between the unilateral and bilateral CI groups.

RESULTS

Children with unilateral CIs performed similarly to children with bilateral CIs on all three experience-dependent tasks. However, children with bilateral CIs significantly outperformed children with unilateral CIs on all three phonological processing tasks. Among the phonological processing tasks, the rapid automatic naming task scores differentiated children with unilateral CIs from children with bilateral CIs.

CONCLUSIONS

Bilateral cochlear implantation may positively impact the phonological processing skills of deaf children.