Benefits of bilateral cochlear implantation in children: a systematic review and meta-analysis

Abstract Objective To systematically evaluate the benefits and risks of bilateral cochlear implantation (BiCI) in children compared with unilateral cochlear implantation (UniCI), with a focus on auditory outcomes, language development, and potential complications. Methods A systematic review and meta-analysis was conducted following PRISMA guidelines and registered in PROSPERO (1128982). Searches were performed in PubMed, ScienceDirect, Scopus, and the Cochrane Library for studies published between 2015 and June 2025, with selective inclusion of earlier high-quality pediatric studies. Eligible studies included children with congenital or early-onset bilateral deafness who received BiCI or UniCI. Primary outcomes were speech perception (especially in noise), sound localisation, and spoken language development. Secondary outcomes included quality of life and adverse effects. Random-effects meta-analyses were performed using standardised mean differences (SMD). Results Fifty studies were included in the qualitative synthesis and 20 in the meta-analyses. BiCI provided significantly better outcomes in speech perception in noise (SMD = + 0.70, p < 0.001) and sound localisation (SMD = + 0.74, p < 0.001), with consistent benefits across study designs and populations. Language development also favoured BiCI (SMD = + 0.65 for receptive vocabulary). Earlier implantation and shorter inter-implant intervals were associated with larger benefits. Surgical and vestibular complications were infrequent and did not exceed those reported for UniCI. Quality-of-life ratings were consistently higher in BiCI users. Conclusion Bilateral cochlear implantation offers a significant but variable advantage over unilateral implantation in children, particularly in noisy environments, spatial hearing, and language acquisition. While language outcomes generally favour BiCI, results show greater heterogeneity compared to auditory measures. Benefits are most robust with early and simultaneous implantation. Although BiCI is a safe and effective intervention, the observed methodological and clinical heterogeneity underscores the need for standardized longitudinal assessments.