This study investigated the effects of hearing history on consonant perception scores and confusion patterns in early implanted youth (i.e., child-implanted) and post-lingually implanted adults (i.e., adult-implanted), as well as in participants with normal hearing (NH) who listened to spectrally degraded (vocoded) stimuli. Vocoded consonant perception improved with chronological age in children with NH. For the cochlear implant (CI) users, more auditory experience and shorter durations of deafness were associated with better consonant perception scores, especially in child-implanted listeners. Individuals in the child-implanted group also made significantly more errors in identifying the voiceless fricative, /θ/, than did adult-implanted listeners. Individual differences in phoneme error patterns could inform personalized intervention strategies, and child-implanted listeners might derive particular benefit from interventions that improve access to formant transitions or high-frequency energy. Moreover, while CI experience and early implantation benefit many CI users of all ages, delayed intervention may be more detrimental to the speech perception outcomes of prelingually deafened than post-lingually implanted individuals.
Jahn et al. (Sun,) studied this question.