Establishment of Reference Values for Early Auditory Preverbal Skills of Children with Cochlear Implants

Auditory and verbal abilities of children with early cochlear implant (CI) surgery usually take some time to develop, and a reference index of early development for horizontal comparisons is urgently needed to guide the mapping process and adjust rehabilitation programs. Therefore, the aim of this study was to establish a reference value for early auditory preverbal skills development in children with CI and investigate the developmental curve and influencing factors for these children. The LittlEARS® Auditory Questionnaire (LEAQ) scores of 287 eligible Chinese participants were obtained at 1, 2, 3, 6, 9, 12, 18, 24, 28, and 36 months interval after CI activation. The median and standard deviation of the LEAQ score of each hearing stage for these children with different activation ages were calculated to establish the reference values. Quadratic regression was conducted to fit the expected developmental curve of the LEAQ score ($$ [0 to 20 months]). With a linear mixed-effects model, we found that the receptive auditory behavior increased rapidly after CI activation, while expressive language skills developed at a steady rate. We also found that the following factors all significantly influenced the LEAQ: the duration of CI use, the development quotient, age of implantation and activation, and the presence of large vestibular aqueduct syndrome or auditory neuropathy spectrum disorder. The reference values and the expected developmental curve for the LEAQ in children with CI established by the present study provides guidance to clinicians and parents as well as realistic expectations regarding language and speech outcomes.