Vowel perception in prelingually deafened children with multichannel cochlear implants.

Vowel perception ability for 16 prelingually deafened children using Nucleus 22-channel cochlear implants was studied at 12, 24, and 36 months postimplantation. Information transmission analysis was used to evaluate the effectiveness of the implants in conveying the essential cues required for accurate vowel identification and whether the cues used varied with experience or device use. Individual vowel identification varied widely with mean scores significantly improving between 12 and 24 months but not between 24 and 36 months. Information transmission scores for all vowel features (fronting, height, duration, and diphthongization) increased dramatically between 12 and 36 months. Results indicated that vowel height and vowel fronting were the most salient features for the subject group. There were no differences in the pattern of confusions made across test sessions or across groups when divided into "poor" and "good" users. However, there was evidence that the "good" users made better use of higher frequency formant information than the "poor" users. The results of the present study add to the accumulation of evidence pointing to the great benefit that cochlear implantation can provide to prelingually deafened children. Overall performance for the vowel recognition test used in this study was quite high and analysis of the childrens' errors suggested that their cochlear implants were reasonably effective at conveying the most essential spectral information required for vowel discrimination.