# Speech-Evoked Cortical Auditory Potentials as Biomarkers of Auditory Maturation in Children with Cochlear Implants

## TL;DR

The study finds that speech-evoked brain signals can track auditory development in children with cochlear implants, showing how experience and implant use affect brain maturation.

## Contribution

Speech-evoked cortical auditory potentials are proposed as objective biomarkers for auditory cortical maturation in pediatric cochlear implant users.

## Key findings

- P1 latency was significantly longer in cochlear implant users than in normal-hearing children for low- and high-frequency speech stimuli.
- P1 latency in cochlear implant users decreased with longer implant-use duration, indicating experience-dependent cortical plasticity.
- No significant difference in P1 latency was observed for mid-frequency speech stimuli between the two groups.

## Abstract

What are the main findings?

P1 latency—a cortical marker of auditory maturation—was significantly longer in cochlear implant (CI) users than in age-matched normal-hearing (NH) children for low- (/m/) and high-frequency (/t/) speech stimuli.

In NH children, P1 latency shortened with increasing age, while in CI users it decreased with longer implant-use duration, indicating experience-dependent cortical plasticity.

No significant difference in P1 latency was observed for mid-frequency (/g/) stimuli, suggesting frequency-specific maturation dynamics.

What is the implication of the main finding?

Speech-evoked cortical auditory evoked potentials (CAEPs) provide a reliable, objective biomarker for assessing auditory cortical development and plasticity in pediatric CI users.

Integrating multi-frequency CAEP testing into peri-operative and rehabilitation protocols can help monitor cortical maturation, optimize implant programming, and guide individualized auditory-verbal therapy.

Objectives: This study aimed to evaluate auditory cortical maturation in pediatric cochlear implant (CI) users using speech-evoked cortical auditory evoked potentials (CAEPs) and to compare P1 latency responses with age-matched normal-hearing (NH) peers. Secondary objectives included examining the relationship between P1 latency, age, and duration of implant use to assess experience-dependent cortical plasticity. Materials and Methods: Seventy children were enrolled, including 40 prelingually deaf CI users and 30 NH controls matched for age and sex. CAEPs were recorded using the HEARLab system with three speech tokens representing low (/m/), mid (/g/), and high (/t/) frequencies, presented at 55 dB SPL in a free-field setup. The P1 component was identified as the first positive deflection between 50 and 150 ms after stimulus onset. Group comparisons were performed using Student’s t-test, and correlations between P1 latency, age, and implant-use duration were analyzed using the Pearson correlation test (p < 0.05). Results: Mean P1 latencies were significantly longer in CI users than in NH peers for the /m/ and /t/ stimuli (p = 0.036 and p = 0.045, respectively), while no significant difference was found for /g/ (p = 0.542). In NH children, P1 latency negatively correlated with age (r = −0.44, p < 0.05), indicating maturation-related shortening. Among CI users, longer implant-use duration was associated with shorter P1 latencies across all speech tokens (/m/: r = −0.37; /g/: r = −0.49; /t/: r = −0.43; p < 0.05 for all). Conclusions: Speech-evoked CAEPs provide a sensitive and objective measure of auditory cortical development in children with cochlear implants. P1 latency reflects both chronological and hearing-age-related maturation, supporting its clinical use as a biomarker for cortical plasticity and rehabilitation progress in pediatric CI care.