Nonword Repetition with Spectrally Reduced Speech

Nonword repetition skills were examined in 24 pediatric cochlear implant users and 18 normal-hearing adult listeners. The normal-hearing adult listeners heard spectrally degraded nonwords that were processed through an acoustic simulation of a cochlear implant designed to mimic the auditory input received by cochlear implant users. Two separate groups of normal-hearing adult listeners assigned perceptual accuracy ratings to the nonword responses of the pediatric cochlear implant users and the normal-hearing adult speakers. Overall, the nonword repetitions of children using cochlear implants were rated as more accurate than the nonword repetitions of the adults. The nonword repetition accuracy ratings from both groups of subjects were correlated with their openand closed-set word recognition scores and with their forward digit spans. However, only the accuracy scores from pediatric cochlear implant users were correlated with measures of speech production accuracy. This finding may reflect the lack of variance in the accuracy ratings and the linguistic analysis of the adults’ nonword repetitions as well as differences in overall fluency of the productions. In terms of overall accuracy, the children performed better on speech perception tasks, while the adults were better on working memory tasks. These results suggest that although the pediatric cochlear implant users had more experience and success in perceiving speech under degraded auditory conditions with their cochlear implant, developmental differences in their memory skills prevent them from performing as well on working memory tasks as mature listeners who were exposed to a spectrally degraded speech for only a short period of time in the laboratory.