Johanna G. Nicholas

Effects of Early Auditory Experience on the Spoken Language of Deaf Children at 3 Years of Age

Objective: By age 3, typically developing children have achieved extensive vocabulary and syntax skills that facilitate both cognitive and social development. Substantial delays in spoken language acquisition have been documented for children with severe to profound deafness, even those with auditory oral training and early hearing aid use. This study documents the spoken language skills achieved by orally educated 3-yr-olds whose profound hearing loss was identified and hearing aids fitted between 1 and 30 mo of age and who received a cochlear implant between 12 and 38 mo of age. The purpose of the analysis was to examine the effects of age, duration, and type of early auditory experience on spoken language competence at age 3.5 yr. Design: The spoken language skills of 76 children who had used a cochlear implant for at least 7 mo were evaluated via standardized 30-minute language sample analysis, a parent-completed vocabulary checklist, and a teacher language-rating scale. The children were recruited from and enrolled in oral education programs or therapy practices across the United States. Inclusion criteria included presumed deaf since birth, English the primary language of the home, no other known conditions that interfere with speech/language development, enrolled in programs using oral education methods, and no known problems with the cochlear implant lasting more than 30 days. Results: Strong correlations were obtained among all language measures. Therefore, principal components analysis was used to derive a single Language Factor score for each child. A number of possible predictors of language outcome were examined, including age at identification and intervention with a hearing aid, duration of use of a hearing aid, pre-implant pure-tone average (PTA) threshold with a hearing aid, PTA threshold with a cochlear implant, and duration of use of a cochlear implant/age at implantation (the last two variables were practically identical because all children were tested between 40 and 44 mo of age). Examination of the independent influence of these predictors through multiple regression analysis revealed that pre-implant–aided PTA threshold and duration of cochlear implant use (i.e., age at implant) accounted for 58% of the variance in Language Factor scores. A significant negative coefficient associated with pre-implant–aided threshold indicated that children with poorer hearing before implantation exhibited poorer language skills at age 3.5 yr. Likewise, a strong positive coefficient associated with duration of implant use indicated that children who had used their implant for a longer period of time (i.e., who were implanted at an earlier age) exhibited better language at age 3.5 yr. Age at identification and amplification was unrelated to language outcome, as was aided threshold with the cochlear implant. A significant quadratic trend in the relation between duration of implant use and language score revealed a steady increase in language skill (at age 3.5 yr) for each additional month of use of a cochlear implant after the first 12 mo of implant use. The advantage to language of longer implant use became more pronounced over time. Conclusions: Longer use of a cochlear implant in infancy and very early childhood dramatically affects the amount of spoken language exhibited by 3-yr-old, profoundly deaf children. In this sample, the amount of pre-implant intervention with a hearing aid was not related to language outcome at 3.5 yr of age. Rather, it was cochlear implantation at a younger age that served to promote spoken language competence. The previously identified language-facilitating factors of early identification of hearing impairment and early educational intervention may not be sufficient for optimizing spoken language of profoundly deaf children unless it leads to early cochlear implantation.

Personal, social, and family adjustment in school-aged children with a cochlear implant.

Objective The present study sought to document the psycho-social adjustment of 181 school-aged deaf children who have had a cochlear implant for 4 or more yr and to examine parental satisfaction with the outcome of the implantation process on their child’s life and on their family’s life in general. Design Three measures were employed. One measure was a self-report instrument designed to assess perceived self-competence in children, one was a rating scale completed by parents that sought to assess the degree of their child’s personal-social adjustment, and the third was a questionnaire given to parents on which they rated their satisfaction with aspects of the cochlear implant and how it had affected their child’s functioning within the context of family life. Results Children generally perceived themselves (and parents perceived their children) as being competent and well adjusted in most aspects of daily life. Parents expressed a generally positive view of cochlear implantation and its effects on family life. None of the social-emotional adjustment measures was significantly related to the speech perception, speech production or language skills the child achieved postimplant. However, the parents’ satisfaction with their child’s cochlear implantation was significantly related to their child’s speech and language achievements. On the perceived self-competence instrument, younger children and those with longer use of the updated SPEAK speech processor gave themselves higher ratings. Parent ratings of their child’s adjustment tended to be higher for girls than for boys, for more rather than less intelligent children, and for children enrolled in private as opposed to public school settings. Conclusions Deaf children who have used a cochlear implant for 4 to 6 yr report that they are coping successfully with the demands of their social and school environment, regardless of their speech and language achievements after implantation. Parents’ ratings indicate that these children are emotionally and socially well adjusted and that they have benefited from cochlear implantation. To the extent that the children and their parents accurately reported their attitudes and feelings regarding their experiences at home and at school, these results represent an impressive level of personal and social adjustment when compared with previous literature on adjustment problems in deaf children. The extent to which these results are associated with cochlear implantation has not been determined and awaits comparative data from children without implants.

Estimating the influence of cochlear implantation on language development in children

Research studies reviewed here have identified a wide variety of factors that may influence a childs auditory, speech and language development following cochlear implantation. Intrinsic characteristics of the implanted child, including gender, family socioeconomic status, age at onset of hearing loss and pre-implant residual hearing may predispose a child to greater or lesser post-implant benefit. Intervention characteristics that may influence outcome include age of the child when deafness is identified and amplification and habilitation is initiated, the communication mode used with the child and the type of classroom/therapy employed. Characteristics of the implant itself include generation of technology used, the age of the child when implant stimulation is initiated, and the amount of time the child has used the implant. These factors interact in unpredictable ways, so that isolated correlations between predictor variables and outcome scores may be difficult to interpret. Results for two independent samples of children tested by different laboratories were compared using multiple regression analysis to take into account relationships among predictor variables. Implant age was a significant predictor, and children in both samples who received a cochlear implant sometime between their first and second birthday achieved oral receptive vocabulary levels within one standard deviation of hearing age-mates. Age at implant accounted for a similar proportion of variance in receptive vocabulary outcome scores in each sample. A unique predictor was then added to each analysis. The addition of pre-implant aided threshold not only increased the total predicted variance, but also increased the effect of implant age as a predictor variable. A different result was observed in the other sample, when the added predictor variable was non-verbal IQ, where the estimated contribution of implant age was reduced. Future studies are advised to control for independent contributions of implant age, non-verbal IQ, and pre-implant aided thresholds when examining expected outcomes.

Rehabilitation factors contributing to implant benefit in children

This study was performed to investigate factors contributing to auditory, speech, language, and reading outcomes after 4 to 6 years of multichannel cochlear implant use in children with prelingual deafness. The analysis controlled for the effects of child, family, and implant characteristics so that the educational factors most conducive to maximum implant benefit could be identified. We tested 136 children from across the United States and Canada. All were 8 or 9 years of age, had an onset of deafness before 3 years of age, underwent implantation by 5 years of age, and resided in a monolingual English-speaking home environment. Characteristics of the child and the family (primarily nonverbal IQ) accounted for approximately 20% of the variance in outcome after implantation. An additional 24% was accounted for by implant characteristics and 12% by educational variables, particularly communication mode. Oral education appears to be an important educational choice for children who have undergone cochlear implantation before 5 years of age.

Effects of communication mode on skills of long-term cochlear implant users

In contrast to predictions by Deaf activists, this group of adolescents with and without cochlear implants had strikingly similar identity beliefs. Both groups indicated a high degree of approval of Bicultural identity statements, which reflect a balanced view of the hearing and deaf cultures. Although the sample was small, inspection of the data indicates that the absolute values and distributional characteristics for the DIDS scores of the two groups were highly similar on all scales except the Hearing identity scale. Because many implant users receive audiological benefit, it is not surprising that they describe emulating the hearing majority as a desirable goal.

Spoken language benefits of extending cochlear implant candidacy below 12 months of age

Objective To test the hypothesis that cochlear implantation surgery before 12 months of age yields better spoken language results than surgery between 12 and 18 months of age. Study Design Language testing administered to children at 4.5 years of age (±2 mo). Setting Schools, speech-language therapy offices, and cochlear implant (CI) centers in the United States and Canada. Participants Sixty-nine children who received a cochlear implant between ages 6 and 18 months of age. All children were learning to communicate via listening and spoken language in English-speaking families. Main Outcome Measure Standard scores on receptive vocabulary, expressive, and receptive language (includes grammar). Results Children with CI surgery at 6 to 11 months (n = 27) achieved higher scores on all measures as compared with those with surgery at 12 to 18 months (n = 42). Regression analysis revealed a linear relationship between age of implantation and language outcomes throughout the 6- to 18-month surgery-age range. Conclusion For children in intervention programs emphasizing listening and spoken language, cochlear implantation before 12 months of age seems to provide a significant advantage for spoken language achievement observed at 4.5 years of age.

Persistent Language Delay Versus Late Language Emergence in Children With Early Cochlear Implantation

PURPOSE The purpose of the present investigation is to differentiate children using cochlear implants (CIs) who did or did not achieve age-appropriate language scores by midelementary grades and to identify risk factors for persistent language delay following early cochlear implantation. MATERIALS AND METHOD Children receiving unilateral CIs at young ages (12-38 months) were tested longitudinally and classified with normal language emergence (n = 19), late language emergence (n = 22), or persistent language delay (n = 19) on the basis of their test scores at 4.5 and 10.5 years of age. Relative effects of demographic, audiological, linguistic, and academic characteristics on language emergence were determined. RESULTS Age at CI was associated with normal language emergence but did not differentiate late emergence from persistent delay. Children with persistent delay were more likely to use left-ear implants and older speech processor technology. They experienced higher aided thresholds and lower speech perception scores. Persistent delay was foreshadowed by low morphosyntactic and phonological diversity in preschool. Logistic regression analysis predicted normal language emergence with 84% accuracy and persistent language delay with 74% accuracy. CONCLUSION CI characteristics had a strong effect on persistent versus resolving language delay, suggesting that right-ear (or bilateral) devices, technology upgrades, and improved audibility may positively influence long-term language outcomes.

The effects of audibility and novel word learning ability on vocabulary level in children with cochlear implants.

Abstract Objectives A novel word learning (NWL) paradigm was used to explore underlying phonological and cognitive mechanisms responsible for delayed vocabulary level in children with cochlear implants (CIs). Methods One hundred and one children using CIs, 6–12 years old, were tested along with 47 children with normal hearing (NH). Tests of NWL, receptive vocabulary, and speech perception at 2 loudness levels were administered to children with CIs. Those with NH completed the NWL task and a receptive vocabulary test. CI participants with good audibility (GA) versus poor audibility (PA) were compared on all measures. Analysis of variance was used to compare performance across the children with NH and the two groups of children with CIs. Multiple regression analysis was employed to identify independent predictors of vocabulary outcomes. Results Children with CIs in the GA group scored higher in receptive vocabulary and NWL than children in the PA group, although they did not reach NH levels. CI-aided pure tone threshold and performance on the NWL task predicted independent variance in vocabulary after accounting for other known predictors. Discussion Acquiring spoken vocabulary is facilitated by GA with a CI and phonological learning and memory skills. Children with CIs did not learn novel words at the same rate or achieve the same receptive vocabulary levels as their NH peers. Maximizing audibility for the perception of speech and direct instruction of new vocabulary may be necessary for children with CIs to reach levels seen in peers with NH.

Interdependence of linguistic and indexical speech perception skills in school-age children with early cochlear implantation.

Objectives: This study documented the ability of experienced pediatric cochlear implant (CI) users to perceive linguistic properties (what is said) and indexical attributes (emotional intent and talker identity) of speech, and examined the extent to which linguistic (LSP) and indexical (ISP) perception skills are related. Preimplant-aided hearing, age at implantation, speech processor technology, CI-aided thresholds, sequential bilateral cochlear implantation, and academic integration with hearing age-mates were examined for their possible relationships to both LSP and ISP skills. Design: Sixty 9- to 12-year olds, first implanted at an early age (12 to 38 months), participated in a comprehensive test battery that included the following LSP skills: (1) recognition of monosyllabic words at loud and soft levels, (2) repetition of phonemes and suprasegmental features from nonwords, and (3) recognition of key words from sentences presented within a noise background, and the following ISP skills: (1) discrimination of across-gender and within-gender (female) talkers and (2) identification and discrimination of emotional content from spoken sentences. A group of 30 age-matched children without hearing loss completed the nonword repetition, and talker- and emotion-perception tasks for comparison. Results: Word-recognition scores decreased with signal level from a mean of 77% correct at 70 dB SPL to 52% at 50 dB SPL. On average, CI users recognized 50% of key words presented in sentences that were 9.8 dB above background noise. Phonetic properties were repeated from nonword stimuli at about the same level of accuracy as suprasegmental attributes (70 and 75%, respectively). The majority of CI users identified emotional content and differentiated talkers significantly above chance levels. Scores on LSP and ISP measures were combined into separate principal component scores and these components were highly correlated (r = 0.76). Both LSP and ISP component scores were higher for children who received a CI at the youngest ages, upgraded to more recent CI technology and had lower CI-aided thresholds. Higher scores, for both LSP and ISP components, were also associated with higher language levels and mainstreaming at younger ages. Higher ISP scores were associated with better social skills. Conclusions: Results strongly support a link between indexical and linguistic properties in perceptual analysis of speech. These two channels of information appear to be processed together in parallel by the auditory system and are inseparable in perception. Better speech performance, for both linguistic and indexical perception, is associated with younger age at implantation and use of more recent speech processor technology. Children with better speech perception demonstrated better spoken language, earlier academic mainstreaming, and placement in more typically sized classrooms (i.e., >20 students). Well-developed social skills were more highly associated with the ability to discriminate the nuances of talker identity and emotion than with the ability to recognize words and sentences through listening. The extent to which early cochlear implantation enabled these early-implanted children to make use of both linguistic and indexical properties of speech influenced not only their development of spoken language, but also their ability to function successfully in a hearing world.

Emergence of speech sounds between 7 and 24 months of cochlear implant use.

Abstract Objectives To investigate the process of speech development in five 42-month-old children with profound deafness who received cochlear implants (CIs) between 19 and 36 months of age and five normal hearing (NH) age mates. Methods Conversational samples were collected and transcribed. Sounds produced correctly within meaningful words (target sounds) and recognizable sounds produced in spontaneous productions (target-less sounds) were analyzed for all 10 children. Results Revealed that there was overlap in the total number of vowels and consonants produced by the two groups. The differences between the two groups were more evident in the target condition, whereas the two groups were more similar in the target-less condition. Discussion The similarities documented in the target-less repertoire of CI and NH children underscore the importance of examining the emerging sound system to predict the end-point sound system in children with CIs. Using target and target-less speech sound comparisons offers a supplementary view of the emergent process of speech sound development and is a valid method of analysis. Results suggest that early implantation may help some children with profound deafness develop speech sounds in a manner similar to NH age mates.