Association Between Cortical Auditory Evoked Potentials Recorded Directly Through Cochlear Implants and Post-Implantation Auditory and Speech Outcomes

Suhail Habib AllahJoseph Attias^*

• University of Haifa, Haifa, Israel

Following recent demonstrations that electrically evoked cortical auditory evoked potentials (eCAEPs) can be recorded directly through cochlear implants (CIs) in both children and adults, this study examined how eCAEP waveform characteristics relate to auditory and speech outcomes in CI users. It also evaluated how age at implantation and current age influence the latencies and amplitudes of the P1–N1–P2 complex within the context of auditory cortical developmental plasticity. The study included 25 children and 12 adults, all bilaterally implanted with Advanced Bionics devices. Intracochlear eCAEPs were recorded from 33 ears in children and 21 ears in adults. Responses were elicited by brief (10 ms) electrical stimulation at the apical electrode of the stimulated CI, while recordings were obtained from basal electrode 13 of the contralateral CI referenced to the case. Each session lasted about 5 minutes. Children were 2.7–16.7 years old (mean 11.5), and adults 18.5–49.1 years (mean 33.8). Age at implantation ranged from 0.5–8.1 years in children (mean 1.75) and 1.6–43.6 years in adults (mean 23.5). Auditory and speech performance were assessed using CAP, SIR, and monosyllabic word recognition in quiet and noise. Reliable eCAEPs containing all obligatory components were obtained from all ears. Children showed significantly shorter P1–N1 latencies and larger amplitudes than adults. Age at implantation emerged as the strongest predictor of cortical latency, with earlier implantation associated with shorter P1–N1 latencies. Most children demonstrated age-appropriate P1 latencies comparable to normal-hearing peers, whereas only adults implanted in early childhood showed similar patterns. Adults more frequently exhibited a split P2 waveform, possibly reflecting altered cortical integration. Significant correlations were found between eCAEP latencies and speech perception, particularly in noise, indicating functional relevance of cortical processing efficiency. Higher CAP and SIR scores were associated with shorter P1–N1 latencies. Overall, the findings provide near-field neurophysiological evidence for sensitive periods in auditory cortical development and highlight intracochlear eCAEPs as an objective biomarker of cortical function and plasticity in CI users. This method supports real-time monitoring of neuroplastic changes and offers a promising platform for translational auditory neuroscience in both pediatric and adult populations.