A comparison of vowel production by children with multichannel cochlear implants or tactile aids: perceptual evidence.

OBJECTIVE: To examine changes in perceived vowel production accuracy over time in prelingually deafened children who use a multichannel cochlear implant (Nucleus 22 channel) or a multichannel tactile aid (Tactaid 7) and to compare the levels of perceived vowel production accuracy attained by the two device groups. DESIGN: The subjects were participants in longitudinal studies of the effects of sensory aids on the development of perceptual, speech, and language skills. As part of these studies, imitative vowel productions were elicited and transcribed before each child received their sensory aid and at 6 mo intervals thereafter. Data for the current study was obtained from the predevice interval and a later interval (postdevice) that was an average of 1.8 yr after the subjects received their respective devices. The subjects' vowel productions were judged for accuracy in matching an imitative model and for correctness of vowel features (height and place). Within-group analyses were completed to determine if vowel production scores improved over the course of the study for each device group. Between group comparisons were performed to examine differences in mean scores at each interval. RESULTS: Before receiving their multichannel devices, the two groups of subjects demonstrated similar imitative vowel production skills. After an average of 1.8 yr of device use, the cochlear implant subjects demonstrated significantly improved production of diphthongs and all vowel categories except low vowels. The Tactaid 7 subjects demonstrated significant improvement only in the production of diphthongs. Thus, cochlear implant recipients' vowel production skills were found to be significantly better than those of the Tactaid 7 users after a comparable amount of device experience. CONCLUSIONS: The vowel production gains of the cochlear implant subjects were similar in amount to those noted in other studies of children who use the Nucleus multichannel cochlear implant and further confirm the potential of this device for improved speech production in prelingually deafened children. The differences between the performance of the two groups demonstrate that vowel production skills improved to a greater degree through use of a multichannel cochlear implant than through use of the Tactaid 7.

Comparison of multichannel tactile aids and multichannel cochlear implants in children with profound hearing impairments.

Speech perception skills of prelingually deafened children who used the multichannel Tactaid 7 (n = 10) were compared to those of a matched group of children who used the Nucleus 22 channel cochlear implant (n = 10). Group scores were compared on a closed-set test of word recognition and on an open-set test of phrase recognition in the pre-device condition and at a post-device interval after an average of 1.5 years of multichannel device use. The results revealed that the scores of the implant users improved significantly between the pre- and post-device intervals on all measures. Moreover, the scores of the implant users were significantly higher than those of the tactile aid users on all measures. In contrast, the scores of the tactile aid users showed negligible change over time, except on a test that evaluated open-set recognition of phrases with both auditory and visual cues. The results suggest that children can learn to recognize words and understand speech without lipreading with a multichannel implant, whereas children who used the multichannel tactile aid demonstrate limited speech recognition skills only if auditory/tactile cues are combined with lipreading.