Purpose: This study investigated long-term speech intelligibility outcomes in 63 prelingually deaf children, adolescents, and young adults who received cochlear implants (CIs) before age 7 (M = 2;11 [years;months], range = 0;8-6;3) and used their implants for at least 7 years (M = 12;1, range = 7;0-22;5).
Method: Speech intelligibility was assessed using playback methods with naïve, normal-hearing listeners.
Results: Mean intelligibility scores were lower than scores obtained from an age- and nonverbal IQ-matched, normal-hearing control sample, although the majority of CI users scored within the range of the control sample. Our sample allowed us to investigate the contribution of several demographic and cognitive factors to speech intelligibility. CI users who used their implant for longer periods of time exhibited poorer speech intelligibility scores. Crucially, results from a hierarchical regression model suggested that this difference was due to more conservative candidacy criteria in CI users with more years of use. No other demographic variables accounted for significant variance in speech intelligibility scores beyond age of implantation and amount of spoken language experience (assessed by communication mode and family income measures).
Conclusion: Many factors that have been found to contribute to individual differences in language outcomes in normal-hearing children also contribute to long-term CI users' ability to produce intelligible speech.