Language development in profoundly deaf children with cochlear implants.

Although cochlear implants improve the ability of profoundly deaf children to understand speech, critics claim that the published literature does not document even a single case of a child who has developed a linguistic system based on input from an implant. Thus, it is of clinical and scientific importance to determine whether cochlear implants facilitate the development of English language skills. The English language skills of prelingually deaf children with cochlear implants were measured before and after implantation. We found that the rate of language development after implantation exceeded that expected from unimplanted deaf children (p < .001) and was similar to that of children with normal hearing. Despite a large amount of individual variability, the best performers in the implanted group seem to be developing an oral linguistic system based largely on auditory input obtained from a cochlear implant.

Language development in children implanted with the CLARION cochlear implant.

This study examined the development of language skills in 23 prelingually, profoundly deaf children following implantation with the CLARION Multi-Strategy Cochlear Implant. Language skills were assessed with the Reynell Developmental Language Scales (RDLS) preoperatively with hearing aids, and compared to postoperative performance after 6 months of Clarion use. The RDLS was administered in each child's preferred mode of communication, either spoken English alone or simultaneous spoken and signed English. Significant improvements were observed in average age-equivalent scores over time, both for receptive and expressive skills, although the absolute language levels of the implanted children remained delayed relative to those of hearing peers of the same chronological age. The children's rate of language growth in the first 6 months of implant use also was calculated. The results from this analysis showed that the Clarion children, on average, progressed at a rate that exceeded that of normal-hearing children of the same language age. There was no significant difference between the language performance of children who used oral versus total communication.

Children with implants can speak, but can they communicate?

English-language skills were evaluated in two groups of profoundly hearing-impaired children with the Reynell Developmental Language Scales, Revised. The first group consisted of 89 deaf children who had not received cochlear implants. The second group consisted of 23 children wearing Nucleus multichannel cochlear implants. The subjects without implants provided cross-sectional language data used to estimate the amount of language gains expected on the basis of maturation. The Reynell data from the group without implants were subjected to a regression by age. On the basis of this analysis, deaf children were predicted to make half or less of the language gains of their peers with normal hearing. Predicted language scores were then generated for the subjects with implants by using the children's preimplant Reynell Developmental Language Scale scores. The predicted scores were then compared with actual scores achieved by the subjects with implants 6 and 12 months after implantation. Twelve months after implantation, the subjects demonstrated gains in receptive and expressive language skills that exceeded by 7 months the predictions made on the basis of maturation alone. Moreover, the average language-development rate of the subjects with implants in the first year of device use was equivalent to that of children with normal hearing. These effects were observed for children with implants using both the oral and total-communication methods.

Speech intelligibility of children with multichannel cochlear implants.

The purpose of this longitudinal study is to document improvements in speech intelligibility in children who have received multichannel cochlear implants, to compare their performance to that of a matched group of children with different levels of hearing loss who use conventional hearing aids. Speech intelligibility was measured by panels of listeners who analyzed recorded speech samples preimplant and at 6-month intervals following implantation. The results of this study demonstrate that prelingually deafened children with the Nucleus multichannel cochlear implant achieved significant improvements in speech intelligibility. By the 4.5- to 7.5-year intervals, the speech intelligibility exceeded 40%.

Enhancement of expressive language in prelingually deaf children with cochlear implants.

Expressive language skills were assessed in two groups of prelingually-deafened children using the Reynell Developmental Language Scales (RDLS). Results from a group of 89 unimplanted subjects provided cross-sectional data which suggested that profoundly deaf children without implants, on average, could only be expected to make 5 months of expressive language growth in one year. Twenty-three children who received cochlear implants made up the second group of subjects and were administered the RDLS at three intervals: preimplant, 6-, and 12-months postimplant. The scores obtained at the post-implant intervals were then compared to scores that would be predicted on the basis of maturation alone, without the implant (these predictions were formulated based on the data obtained from the unimplanted subjects). At the 12-month postimplant interval, the observed mean language score was significantly higher than the predicted score. Although the mean group data were extremely encouraging, wide inter- subject variability was observed. Although the implant subjects, as a group, were substantially delayed compared with their normal hearing peers, their rate of language growth was found to match that of hearing peers, following implantation. Thus, the gap between chronological age and language age, which normally widens over time in deaf children, remained constant. Preliminary analyses over the first 2.5 years post-implant are consistent with this trend. These results suggest that early implantation (before age 3) might be beneficial to profoundly deaf children because the language delays at the time of implantation would be much smaller.

Speech perception and speech production skills of children with multichannel cochlear implants.

The acquisition of speech perception and speech production skills emerges over a protracted time course in congenitally deaf children with multichannel cochlear implants (CI). Only through comprehensive, longitudinal studies can the full impact of cochlear implantation be assessed. In this study, the performance of CI users was examined longitudinally on a battery of speech perception measures and compared with subjects with profound hearing loss who used conventional hearing aids (HA). The average performance of the multichannel cochlear implant users gradually increased over time and continued to improve even after 5 years of CI use. Speech intelligibility was assessed from recordings of the subjects' elicited speech and played to panels of listeners. Intelligibility was scored in terms of percentage of words correctly understood. The average scores for subjects who had used their CI for 4 years or more exceeded 40%.

Speech perception skills of children with multichannel cochlear implants or hearing aids.

Perceptual skills were evaluated at two intervals of cochlear implant (CI) use in 24 children with prelingual deafness who received the Nucleus multichannel CI. Their performance was compared to that of age-matched children with prelingual profound hearing losses who used conventional hearing aids (HAs). The HA subjects were grouped by unaided thresholds: "gold" subjects (pure tone average of 92 dB hearing level) and "silver" subjects (pure tone average of 104 dB hearing level). The CI users' perceptual abilities increased significantly with time. At the "early" interval (mean, 2 months of CI use), performance of the CI and silver HA groups was similar on measures of phoneme, word, and sentence recognition; the gold HA subjects' performance was superior to that of the other groups. At the "late" interval, (mean, 2.5 years of CI use), CI subjects' performance exceeded that of the silver group on all measures, and was similar to that of the gold group on vowel recognition and auditory-plus-visual sentence recognition measures.

Speech intelligibility of implanted children.

The speech intelligibility of 61 prelingually deaf children was measured prior to their receiving a multichannel cochlear implant (CI) and at subsequent intervals. The speech intelligibility of the implanted subjects was compared to that of three groups of subjects with profound hearing loss who used conventional hearing aids (HAs), grouped on the basis of unaided thresholds: "gold" (pure tone average [PTA] = 93 dB hearing level [HL]), "silver" (PTA = 103 dB HL), and "bronze" (PTA > or = 110 dB HL). Intelligibility was measured in terms of the percentage of words from a set of 10 sentences that were correctly understood by a panel of listeners. The speech intelligibility of the implanted subjects increased gradually over time, remaining relatively low throughout the first 2 years of implant use. After that time, the average speech intelligibility of the CI subjects surpassed that of the silver HA users. The gold HA subjects demonstrated speech intelligibility that was markedly better than that of the CI subjects, even after 3 1/2 or more years of implant use.

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.

Variables affecting implant performance in children.

This study examined the variables that contribute to the large individual differences in the speech perception skills of children with the Nucleus multichannel cochlear implant. Sixty-one children were tested on four measures of speech perception: two tests of closed-set word recognition, one test of open-set recognition of phrases, and one open-set monosyllabic word test, scored on the basis of the percentage of phonemes as well as words identified correctly. The results of a series of multiple regression analyses revealed that the variables of processor type, duration of deafness, communication mode, age at onset of deafness, length of implant use, and age implanted accounted for roughly 35% of the variance on two tests of closed-set word recognition, and 40% of the variance on measures that assessed recognition of words or phonemes in an open set. Length of implant use accounted for the most variance on all of the speech perception measures.

Single-channel to multichannel conversions in pediatric cochlear implant recipients.

Speech perception skills were measured in five children who had received a 3M/House single-channel cochlear implant and were subsequently upgraded to a multichannel cochlear implant (Nucleus). A rationale was developed based upon performance with the single-channel device and anticipated performance with the multichannel device. All subjects demonstrated improved acoustic thresholds with the multichannel device. Three of the children demonstrated improvements on identification tasks and two on word recognition tasks.

A comparison of speech discrimination with cochlear implants and tactile aids.

This study investigates patterns of speech discrimination in profoundly hearing-impaired children who have received cochlear implants or tactile aids. The change/no change procedure was used to assess speech discrimination in these children. Three groups of subjects were tested: the first group used 3M/House single-channel cochlear implants; the second group used Nucleus 22-channel cochlear implants; and the third group used two-channel Tactaid II+ vibrotactile aids. Nine contrasts were constructed that assessed discrimination of suprasegmental and segmental speech features. Subjects were presented with stimulus trials in which stimuli changed during the trial or in which stimuli remained the same. Hits, misses, false alarms, and correct rejections were tallied and d' values were calculated for individual subjects for each contrast. Results indicated that different patterns of speech discrimination are provided by the three sensory prosthetic devices. For all contrasts, mean discrimination performance with the Nucleus device was better than that observed for the other two devices, despite the shorter duration of subject experience with this cochlear implant. In addition, interactions between device and speech contrast were not observed. Examination of individual subject performance revealed that each device group had a distribution of good to poor performers. The results suggest that the change/no change procedure is able to provide information regarding speech perception through sensory prosthetic devices despite existing differences in vocabulary and language skills of subjects.

Prelingually deafened children's performance with the nucleus multichannel cochlear implant.

The speech perception abilities of 19 children with onset of deafness before age 3 years was examined after they received the Nucleus multichannel cochlear implant. The children were divided into two groups based on age at onset of deafness: children with congenital deafness (n = 8) and children with onset of deafness after birth but before age 3 (n = 11). There was no statistically significant difference between the scores of the two groups of subjects on 12 of the 13 speech perception tests administered. This finding suggests that children who are born deaf have the potential to derive the same benefit from cochlear implants as do children who have had some exposure to spoken language before the onset of their deafness. Examination of performance in terms of communication mode revealed that prelingually deafened children with implants who used oral communication obtained significantly higher scores on only 2 of the 13 speech perception measures than did children who used total communication. The data suggest that communication mode does not appear to account for large differences in speech perception performance among prelingually deafened children with multichannel cochlear implants.

Longitudinal evaluation of communication skills of children with single- or multichannel cochlear implants.

Performance on speech perception, speech production, and language tests was measured over time in children who used the 3M/House or the Nucleus cochlear implant. The speech perception and production results demonstrated higher performance levels and faster rates of learning for the multichannel than for the single-channel users. The performance of the children with the single-channel implant on the speech perception and production measures reached a plateau by 1.5 years post implant, whereas the children using the multichannel device continued to show improvement after 2 or more years of implant use. Changes in language were limited over time with no obvious difference in performance as a function of type of implant.

Effect of age at onset of deafness on children's speech perception abilities with a cochlear implant.

The speech perception abilities of 37 children with cochlear implants (single-channel or multichannel) were examined as a function of age at onset of deafness. There was no significant difference in the speech perception abilities of implanted children who were born deaf and those of implanted children who lost their hearing during the first 3 years of life. In contrast, the performance of children whose age at onset of deafness was 5 years or later was significantly better than that of the children with congenital or early-acquired deafness on tests of stress pattern categorization, closed-set word identification, open-set identification of common phrases, and lipreading enhancement.