The impact of prematurity on cochlear implant outcomes: A case-control study

Despite a higher prevalence of hearing loss in preterm-born infants, cochlear implantation (CI) outcome remains underexplored in this unique subpopulation. We aimed to compare long-term hearing outcomes between preterm- and term-born infants undergoing CI and identify prognostic factors of hearing outcomes among preterm infants post-CI.

This retrospective case-control study compared preterm infants (study group) with two control groups who underwent CI: One group of term infants was matched for hearing loss etiology and the other group was comprised of term infants with a genetic etiology [connexin-26 (GJB2)], the benchmark for favorable CI outcomes. Subgroup analyses were based upon birth weight and gestational age. Primary outcomes included long-term speech reception threshold (SRT) and monosyllabic word identification (HAB) scores.

A total of 161 implanted ears were included: 35 (22%) in the study group, 63 (39%) in the etiology-matched control group, and 63 (39%) in the GJB2 group. SRT was significantly lower in the GJB2 group compared to the study group (p = 0.007) but not between the study and the etiology-matched control group (p = 0.79). HAB scores were comparable among the three groups. A subgroup analysis revealed significant differences in word identification by birth weight, particularly in the <1000 g group. A linear mixed model analysis indicated significant improvements in HAB scores over time for all groups (p < 0.0001), with comparable HAB progress (p = 0.98).

Our findings suggest that prematurity does not significantly impact speech perception outcomes among CI recipients. Low birth weight in preterm infants, however, emerged as a negative prognostic factor for language perception outcomes.