Pediatric cortical auditory evoked potential N1 as a biomarker of auditory cortical maturation

Abstract

Cortical auditory evoked potentials (CAEPs) are widely used as objective measures of auditory cortical development and audibility in children. P1 latency is established as a pediatric CAEP biomarker, but the role of the N1 component is less clearly defined. This review does not simply describe pediatric N1 responses; it critically assesses whether N1-related measures can be considered pediatric biomarkers of auditory cortical maturation and intervention outcome when judged against contemporary biomarker-qualification criteria. A clinical narrative review of peer-reviewed pediatric CAEP literature was conducted, with explicit inclusion and exclusion criteria and a stated rationale for designating studies as central N1 evidence versus contextual or methodological references. Emphasis was placed on N1 latency, N1 detectability, P1–N1 and N1–P2 measures, P1–N1–P2 morphology, and electrically evoked CAEPs. N1 is developmentally late-emerging, generator-heterogeneous, and strongly dependent on stimulus rate and interstimulus interval (ISI); the negativity labeled N1 in infants and very young children may not be generator-equivalent to the adult N1. In normal-hearing children, N1 detectability increases with age and becomes more reliable from approximately 7–9 years when long ISIs are used. In pediatric cochlear implant (CI) users, early implantation (≤3.5 years) is associated with more typical N1 emergence, whereas late implantation (≥7 years) is associated with reduced or absent N1. Evidence for N1 latency as a standalone outcome predictor is mixed: a scalp electrically evoked CAEP study found no association with auditory or speech outcomes, whereas a recent direct intracochlear study reported associations between shorter P1–N1 latencies and better outcomes. N1-related CAEP measures are best regarded as complementary, not standalone, pediatric biomarkers, with greatest practical value in school-age children. N1 emergence is more interpretable than N1 latency alone. Longitudinal, protocol-standardized, multisite studies with explicit biomarker-category framing are needed.