A short-term longitudinal study of vocal development in young children with simultaneous bilateral cochlear implants

Objectives/hypothesis: Vocal development is crucial for children's speech and language acquisition, allowing them to produce sounds, form words, and construct sentences for verbal communication. This study examined the vocal development trajectory in children who received early simultaneous bilateral cochlear implants (CIs) and compared it to age-matched children with typical hearing (TH). Study design: Case-control study design. Methods: Participants included nine children who received simultaneous bilateral CIs between 7 and 20 months of age and eight age-matched children with TH. Parent-child play interactions were video- and audio-recorded at 6-month intervals. Child vocalizations were categorized into four categories: noncanonical babbling, canonical babbling, words, and sentences. Developmental trajectories and group differences were analyzed over three points: initial visit, 6 months, and 12 months after the initial visit (mean age at the first session: 19.76 months; standard deviation: 4.89; range: 12–28 months). Results: Both groups showed an increase in total vocalizations and advanced forms over 1 year. However, the CI group produced a significantly lower proportion of words and sentences and a higher proportion of noncanonical babbling than the TH group. Conclusions: Although children with early-identified hearing loss and simultaneous bilateral CIs make significant progress in vocal development, their vocal milestones remain delayed compared to those of their peers with TH. These children do not fully catch up in vocal development within 1 to 2 years of bilateral CI use. These findings highlight the need for targeted support and early intervention for children with CIs and their parents.