Effects of hearing aids on early prelingual auditory development in children with unilateral cochlear implantation: a linear mixed model for longitudinal data.

Introduction: We conducted a liner mixed model to explore the two-year early prelingual auditory development (EPLAD) of children with and without hearing aids (HAs) after unilateral cochlear implantation (CI) through a longitudinal study.

Methods: 86 children with unilateral CI were divided into CI + HA (46) and CI (40) groups. Their EPLAD was assessed using the Infant Toddler Meaningful Auditory Integration Scale (IT/MAIS) before CI and at 1st, 3rd, 6th, 12th, 18th, and 24th months post-activation. A spline function described the EPLAD trajectory, and a best-fitting curve predicted IT/MAIS score changes over time. A linear mixed model analyzed the effects of HAs on EPLAD.

Results: CI + HA group had significantly higher IT/MAIS scores pre-op and up to 18 months post-CI (p < 0.01). There was no significant difference in the trajectory of EPLAD among different sex and age groups (p > 0.05). ITMAIS, sound detection and sound recognition trajectory of CI + HA group was significantly different from that of CI group (p < 0.01). We constructed a predictive score of IT/MAIS, sound detection and sound recognition over time with high accuracy (R = 0.99).

Conclusions: Most of studies about the effects of HAs on auditory development after CI merely conducted cross-sectional approach, which cannot reflect the real changes of individuals. For children with unilateral cochlear implant, wearing hearing aids in the contralateral ear can continuously improve EPLAD. The auditory development of individual is a dynamic process, and longitudinal study is more advantage to explore the real differences.