Limited use and benefit of residual low-frequency hearing in children with cochlear implants

Introduction This study aimed to evaluate the use and benefit of preserved low-frequency acoustic hearing in children with cochlear implants. Cochlear implantation with hearing preservation offers potential benefits by allowing for the combined use of electrical and acoustic hearing in children. However, the extent to which preserved hearing impacts real-life auditory outcomes is unclear. Methods We conducted a cross-sectional, within-subject study involving 14 pediatric patients (19 ears) who underwent successful hearing preservation cochlear implantation. Participants were assessed on speech perception in noise, pitch discrimination, melody identification, and prosody perception, under two conditions: (1) the test condition, which was their everyday listening configuration—either electroacoustic stimulation or electro-natural stimulation (ENS), and (2) the control condition, where their ear canal was plugged, removing access to any preserved hearing. Results Only two ears used an electroacoustic stimulation system; the rest used their cochlear implant without any acoustic amplification, that is, ENS. No statistically significant improvements were observed when residual hearing was accessible, although there was a trend toward better music perception in the test condition. Better low-frequency residual hearing was associated with better pitch discrimination and melody identification. Excitation pattern analysis showed that the level of residual hearing in the study cohort provided limited access to low-frequency acoustic cues for the test stimuli used. Discussion The cohort showed limited use and little benefit from preserved acoustic hearing. Further research should determine if the provision of appropriate amplification would lead to better outcomes and explore why electroacoustic stimulation systems are not commonly used in children with preserved acoustic hearing.