Multifactorial determinants of auditory outcomes in pediatric cochlear implantation: A long-term longitudinal study

Early cochlear implantation (CI) is considered a key determinant of auditory development in children with severe-to-profound sensorineural hearing loss. However, long-term outcomes remain highly variable and still incompletely understood. This study aimed to evaluate the long-term impact of age at implantation and other modifying variables in a large pediatric CI cohort.

A retrospective longitudinal cohort study was conducted including 588 implanted ears from 494 children aged ≤10 years. Speech recognition scores (SRS) at 65 dB SPL were assessed longitudinally up to 10 years after implantation. Patients were stratified according to age at implantation (<12 months, 1-2 years, 3-5 years, 6-8 years, and 9-10 years).

Earlier implantation was associated with significantly superior SRS at all follow-up intervals (p < 0.001). Children implanted before 12 months achieved the highest outcomes, with 100% reaching SRS >75% at 10 years, whereas those implanted at 9-10 years showed substantially lower performance. Prior hearing aid use was associated with better long-term outcomes, becoming significant from 6 years onward (p = 0.010). Perimodiolar electrodes demonstrated superior early performance and remained an independent predictor of higher 10-year SRS (p = 0.005). In multivariable analysis, only age at implantation (p = 0.004) and electrode array type (p = 0.005) remained independently associated with long-term results.

Age at implantation is the strongest determinant of long-term speech recognition outcomes in pediatric CI recipients. Earlier implantation not only improves average performance but also reduces outcome variability. Electrode design and prior auditory stimulation further modulate outcomes, supporting a multifactorial model of auditory development.