Phoneme Perception in Children With Bilateral Cochlear Implants or Hearing Aids in Quiet, Noise, and Reverberation

OBJECTIVES: The assessment of aided phoneme perception is essential in validating whether hearing aids and cochlear implants adequately meet the amplification and rehabilitation needs of children. Phonemes are commonly used in such assessments to minimize the influence of semantic context and vocabulary knowledge. Traditionally, they have been presented by clinicians using their own voices. This study directly compared the performance of phoneme detection, discrimination, and identification among children with normal hearing, children using hearing aids, children with cochlear implants, and adults with normal hearing. Laboratory procedures and recorded sound files were used throughout. In addition, phoneme discrimination performance was assessed in challenging acoustic environments-specifically those with noise and/or reverberation-mirroring the types of settings children frequently encounter. DESIGN: A total of 60 children and 42 adults participated in the study. The children had an average age of 10 ± 2 yrs, and the adults an average age of 27 ± 5 yrs. The children were divided into 3 groups of 20: those with normal hearing, those using bilateral hearing aids, and those with bilateral cochlear implants. Children with hearing devices were recruited through the Copenhagen Hearing and Balance Center (Rigshospitalet, Denmark) and were tested using their own devices, all fitted according to present best practices. Aided phoneme detection and identification were assessed using the Ling 6(HL) CD sound files, while phoneme discrimination was evaluated using a subset of the DANOK speech corpus. Testing was conducted in a spatial hearing laboratory to examine the impact of noise and reverberation on performance. RESULTS: The results of this study indicate that, aside from minor differences in low-frequency speech phonemes, there were no significant differences between children with hearing aids and those with cochlear implants in phoneme detection, identification, or discrimination across a range of acoustic conditions. All children demonstrated Ling sound detection thresholds in quiet within normal limits, with average thresholds across all Ling sounds below 20 dB HL for all groups (rising to a maximum average of 22 dB HL when analyzed per Ling sound and participant group). Phoneme discrimination was significantly affected by reverberation and noise in all children-more so than in adults-with the most pronounced effects observed in children using hearing aids or cochlear implants. CONCLUSIONS: The procedures for aided phoneme detection, discrimination, and identification presented in this study are valuable tools for objectively assessing outcomes and validating benefit in children using hearing aids and cochlear implants. This is particularly important for children with cochlear implants, as electroacoustic verification through real-ear measures is not possible for these devices. The results suggest that phoneme perception in children with hearing aids and those with cochlear implants-despite the fundamentally different nature of these technologies (acoustic versus electric stimulation)-does not differ significantly. The reduced performance in noisy and reverberant conditions among children, especially those with hearing devices, underscores the importance of optimizing signal to noise ratios and acoustic environments in children's everyday settings to support speech perception, auditory development, and overall wellbeing.