Auditory Outcomes in Children Who Undergo Cochlear Implantation Before 12 Months of Age: A Systematic Review

ObjectiveTo systematically review the literature to determine auditory outcomes of cochlear implantation in children <= 12 months old. Data SourcePubMed, EMBASE, Medline, CINAHL, Cochrane, Scopus, and Web of Science databases were searched from inception to 9/1/2021 using PRISMA guidelines. Review MethodsStudies analyzing auditory outcomes after cochlear implantation (CI) in children <= 12 months of age were included. Non-English studies and case reports were excluded. Outcome measures included functional and objective auditory results. Two independent reviewers evaluated each abstract and article. Heterogeneity and bias across studies were evaluated. ResultsOf 305 articles identified, 17 met inclusion criteria. There were 642 children ages 2 to 12 months at CI. The most common etiologies of hearing loss were congenital CMV, meningitis, idiopathic hearing loss, and GJB2 mutations and other genetic causes. All studies concluded that early CI was safe. Overall, outcomes improved following early CI: IT-MAIS (9 studies), LittlEARS (4 studies), PTA (3 studies), CAP (3 studies), GASP (3 studies), and LNT (3 studies). Nine studies compared outcomes to an older implantation group (>12 months); of these (n = 450 early CI, n = 1189 late CI), 8 studies showed earlier CI achieved comparable or better auditory outcomes than later implantation, whereas 1 study (n = 120) concluded no differences in speech perception improvement. ConclusionAuditory outcomes were overall improved in children <= 12 months old undergoing CI. Studies that compared early to late CI demonstrated similar or better auditory outcomes in early implantation group. Given the comparable safety profile and critical time period of speech and language acquisition, earlier CI should be considered for infants with hearing loss.