Longitudinal Evaluation of Auditory and Speech Performance in Pediatric Cochlear Implant Recipients Using IT-MAIS, MESP, CAP, and SIR Scales

Considerable variability in auditory and speech outcomes among pediatric cochlear implant (CI) recipients has raised ongoing debate regarding whether early auditory perception directly determines later speech intelligibility, particularly in tonal language environments where pitch cues are critical for communication. This longitudinal study evaluated 64 prelingually deaf children aged 1-5 years over 12 months following unilateral implantation, integrating four standardized behavioral scales-the Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS), Categories of Auditory Performance (CAP), Monosyllabic-Trochee-Polysyllabic Word Test (MESP), and Speech Intelligibility Rating (SIR)-together with cortical auditory evoked potentials (CAEP). All measures demonstrated significant time-dependent improvement (p < 0.001): IT-MAIS and CAP increased rapidly within 3 months post-activation, followed by progressive gains in MESP and SIR reflecting enhanced speech perception and intelligibility. Multiple regression analysis showed that CAP at 3 months was significantly associated with SIR outcomes at 12 months (β = 0.201, p = 0.010), explaining 26.6% of the variance, supporting a hierarchical relationship between early auditory comprehension and later expressive language development. Furthermore, P1 latency shortening on CAEP correlated with higher SIR scores (r = 0.275, p = 0.028), supporting cortical plasticity as a neural mechanism underlying behavioral recovery. No significant between-group differences were observed for most auditory and speech perception measures. However, SIR scores at 12 months were modestly higher in children with normal cochlear anatomy. Overall developmental trajectories remained comparable between groups, suggesting that functional auditory experience plays a major role in rehabilitation outcomes. These findings provide longitudinal behavioral and electrophysiological evidence suggesting that early auditory integration is associated with later speech production outcomes. The proposed multimodal framework offers a reproducible, evidence-based approach for monitoring auditory-speech trajectories and guiding individualized rehabilitation in pediatric CI users.