Effects of the inter-implant interval and listening condition on speech perception in children with sequential bilateral cochlear implants

Objectives: The purpose of this study was to investigate the effects of the inter-implant interval and listening condition on speech perception in children with sequential bilateral cochlear implants (BiCIs) and to assess which factors can explain variances in speech perception scores in noise in children with BiCIs. Methods: Thirty children with BiCIs and fifteen children with unilateral cochlear implants (UniCIs) were included in this study. They received the first cochlear implant (CI) before 3.5 years of age and ranged from 7 to 13 years 11 months at the time of the study. The children with BiCIs were divided into two groups according to their inter-implant interval: Children with short inter-implant intervals (SIIIs) and children with long inter-implant intervals (LIIIs). Speech perception in quiet and noise (+8 dB SNRs) was measured by the open-set monosyllabic word tests. Results: Children with CIs performed significantly better in quiet than in noise (p <.001), and children with SIIIs showed the greater performance on phoneme scores in quiet and noise conditions (p <.001). Age at the second CI and the inter-implant interval contributed significantly to the phoneme scores in noise for children with BiCIs (p <.01). Conclusion: A shorter time interval resulted in better speech perception in noise than a longer time interval. For children with BiCIs, age at the second CI and inter-implant interval play critical roles in developing speech perception in noise.