Influence of implantation age on school-age language performance in pediatric cochlear implant users.

OBJECTIVE: This study examined specific spoken language abilities of 160 children with severe-to-profound sensorineural hearing loss followed prospectively 4, 5, or 6 years after cochlear implantation. STUDY SAMPLE: Ninety-eight children received implants before 2.5 years, and 62 children received implants between 2.5 and 5 years of age. DESIGN: Language was assessed using four subtests of the Comprehensive Assessment of Spoken Language (CASL). Standard scores were evaluated by contrasting age of implantation and follow-up test time. RESULTS: Children implanted under 2.5 years of age achieved higher standard scores than children with older ages of implantation for expressive vocabulary, expressive syntax, and pragmatic judgments. However, in both groups, some children performed more than two standard deviations below the standardization group mean, while some scored at or well above the mean. CONCLUSIONS: Younger ages of implantation are associated with higher levels of performance, while later ages of implantation are associated with higher probabilities of continued language delays, particularly within subdomains of grammar and pragmatics. Longitudinal data from this cohort study demonstrate that after 6 years of implant experience, there is large variability in language outcomes associated with modifiers of rates of language learning that differ as children with implants age.

Moving towards accurate and early prediction of language delay with network science and machine learning approaches.

Due to wide variability of typical language development, it has been historically difficult to distinguish typical and delayed trajectories of early language growth. Improving our understanding of factors that signal language disorder and delay has the potential to improve the lives of the millions with developmental language disorder (DLD). We develop predictive models of low language (LL) outcomes by analyzing parental report measures of early language skill using machine learning and network science approaches. We harmonized two longitudinal datasets including demographic and standardized measures of early language skills (the MacArthur-Bates Communicative Developmental Inventories; MBCDI) as well as a later measure of LL. MBCDI data was used to calculate several graph-theoretic measures of lexico-semantic structure in toddlers' expressive vocabularies. We use machine-learning techniques to construct predictive models with these datasets to identify toddlers who will have later LL outcomes at preschool and school-age. This approach yielded robust and reliable predictions of later LL outcome with classification accuracies in single datasets exceeding 90%. Generalization performance between different datasets was modest due to differences in outcome ages and diagnostic measures. Grammatical and lexico-semantic measures ranked highly in predictive classification, highlighting promising avenues for early screening and delineating the roots of language disorders.

Spoken language development in children following cochlear implantation.

CONTEXT: Cochlear implantation is a surgical alternative to traditional amplification (hearing aids) that can facilitate spoken language development in young children with severe to profound sensorineural hearing loss (SNHL). OBJECTIVE: To prospectively assess spoken language acquisition following cochlear implantation in young children. DESIGN, SETTING, AND PARTICIPANTS: Prospective, longitudinal, and multidimensional assessment of spoken language development over a 3-year period in children who underwent cochlear implantation before 5 years of age (n = 188) from 6 US centers and hearing children of similar ages (n = 97) from 2 preschools recruited between November 2002 and December 2004. Follow-up completed between November 2005 and May 2008. MAIN OUTCOME MEASURES: Performance on measures of spoken language comprehension and expression (Reynell Developmental Language Scales). RESULTS: Children undergoing cochlear implantation showed greater improvement in spoken language performance (10.4; 95% confidence interval [CI], 9.6-11.2 points per year in comprehension; 8.4; 95% CI, 7.8-9.0 in expression) than would be predicted by their preimplantation baseline scores (5.4; 95% CI, 4.1-6.7, comprehension; 5.8; 95% CI, 4.6-7.0, expression), although mean scores were not restored to age-appropriate levels after 3 years. Younger age at cochlear implantation was associated with significantly steeper rate increases in comprehension (1.1; 95% CI, 0.5-1.7 points per year younger) and expression (1.0; 95% CI, 0.6-1.5 points per year younger). Similarly, each 1-year shorter history of hearing deficit was associated with steeper rate increases in comprehension (0.8; 95% CI, 0.2-1.2 points per year shorter) and expression (0.6; 95% CI, 0.2-1.0 points per year shorter). In multivariable analyses, greater residual hearing prior to cochlear implantation, higher ratings of parent-child interactions, and higher socioeconomic status were associated with greater rates of improvement in comprehension and expression. CONCLUSION: The use of cochlear implants in young children was associated with better spoken language learning than would be predicted from their preimplantation scores.

Validity of the MacArthur-Bates Communicative Development Inventories for measuring language abilities in children with cochlear implants.

PURPOSE: To examine the validity of the MacArthur-Bates Communicative Development Inventories (CDI) for measuring language abilities in children with profound hearing loss who are using cochlear implants. METHOD: Twenty-four children with cochlear implants and their mothers participated in this study. Children ranged in age from 32 months to 86 months (the majority were 32 to 66 months old). The number of months postimplantation ranged from 3 to 60 (the majority were around 24 months). Mothers completed the CDI before behavioral testing. Behavioral measures included the Reynell Developmental Language Scales and measures of vocabulary and grammar from a spontaneous language sample. RESULTS: Both the Words and Gestures and the Words and Sentences forms of the CDI were shown to have excellent validity for this sample of children, if they had language that was in the range measured by the instrument. Correlations with behavioral measures ranged from .41 to .93 and were comparable to those reported for children with typical development. CONCLUSIONS: The CDI forms are valid tools to use with children who are using cochlear implants and who are in the early stages of language development, even if they are older than the norming sample. Age-equivalence may be obtained if children score below the median for the oldest age norms. They may also be used to describe the language of children who are not at ceiling. Specific recommendations for interventionists are provided.

Nonword repetition and language development in 4-year-old children with and without a history of early language delay.

PURPOSE: This study examined the usefulness of the Nonword Repetition Test (NRT; C. Dollaghan & T. F. Campbell, 1998) with 4-year-old children and the relationship among the NRT, language, and other aspects of mental processing. METHOD: The NRT was administered to 64 children at 4 years of age; 44 had a history of typical language development (HTD), and 20 had a history of language delay (HLD) at 16 months of age. Study 1 compared methods of scoring phoneme errors to determine whether the NRT was appropriate for this age group. Study 2 examined whether the NRT differentiated HTD from HLD. Study 3 examined the relations among scores on the NRT and standardized tests of language and mental processing. RESULTS: The NRT was found to be appropriate for 4-year-old children. Although all children had normal language abilities at the time of the study, the NRT (and several aspects of language and mental processing) differentiated between HTD and HLD. Relations among the NRT and other measures of language and mental processing were different from those previously reported, an unexpected finding that is inconsistent with traditional accounts of working memory and its relation to language development. Potential explanations are explored, and some directions for future research are suggested.

Categorization and Its Developmental Relation to Early Language.

Three studies examine the developmental relation between early linguistic and cognitive achievements. Studies 1 and 2 attempt to replicate previous findings of a strong temporal link between the ages at there is a sharp rise in new nominal productions and the appearance of 2-category grouping using a longitudinal design. Studies 1 and 2 differ principally in whether the same stimuli were employed each time the children's categorization was tested or whether different stimuli were employed. Study 3 compares the categorization performance of children identified as late talkers to age-matched and language-matched controls cross-sectionally. Our findings consistently show that children's ability to classify objects in a spatial of temporal order is independent of advances in productive vocabulary growth. These results suggest that although children's developing knowledge of object categories may underlie developments in categorization and naming such developments depend on other abilities as well Studyin the past experiences of the child and the particular context in which the behavior is exhibited may be a more meaningful approach to understanding changes in categorization and ultimately its relation to language.

Language development in children at risk for language impairment: cross-population comparisons.

At 3 years of age the spontaneous language of 17 typically developing children was compared to two groups of toddlers who were at risk for language delay for very different reasons. One at-risk group, late talkers, appeared normal in all respects except for their delayed language. These 20 children scored at or below the fifteenth percentile for expressive vocabulary on the MacArthur Communicative Development Inventory (Fenson et al., 1993) when originally identified at 20-27 months of age and within the normal range on the Bayley Scales of Infant Development (Bayley, 1969). The other group, 21 children with unilateral focal brain injury, suffered localized damage to their brain prenatally, perinatally, or within the first 6 months of life. Results indicated that both of the at-risk groups were still significantly lower in vocabulary diversity and grammar at 3 years of age. There was also significantly greater variability in the at-risk groups than in the control groups, and in the children with focal brain injury than in the late talkers in both areas. The importance of language comprehension to development in this period was supported by two findings. First, children with focal brain injury had significantly lower scores than late talkers on the Index of Productive Syntax, a test of emerging grammar, and had been lower in comprehension on a standardized test of language comprehension a year earlier. Second, late talkers with delay in comprehension as well as production had significantly lower scores on IPSyn than those with normal comprehension, suggesting that they are at greater risk for continued delay. Qualitative analyses indicated that the at-risk groups produced the same kinds of errors, but that late talkers produced a substantially greater proportion of errors in obligatory contexts than did children with focal brain injury.

Language development after cochlear implantation: an epigenetic model.

Growing evidence supports the notion that dynamic gene expression, subject to epigenetic control, organizes multiple influences to enable a child to learn to listen and to talk. Here, we review neurobiological and genetic influences on spoken language development in the context of results of a longitudinal trial of cochlear implantation of young children with severe to profound sensorineural hearing loss in the Childhood Development after Cochlear Implantation study. We specifically examine the results of cochlear implantation in participants who were congenitally deaf (N = 116). Prior to intervention, these participants were subject to naturally imposed constraints in sensory (acoustic-phonologic) inputs during critical phases of development when spoken language skills are typically achieved rapidly. Their candidacy for a cochlear implant was prompted by delays (n = 20) or an essential absence of spoken language acquisition (n = 96). Observations thus present an opportunity to evaluate the impact of factors that influence the emergence of spoken language, particularly in the context of hearing restoration in sensitive periods for language acquisition. Outcomes demonstrate considerable variation in spoken language learning, although significant advantages exist for the congenitally deaf children implanted prior to 18 months of age. While age at implantation carries high predictive value in forecasting performance on measures of spoken language, several factors show significant association, particularly those related to parent-child interactions. Importantly, the significance of environmental variables in their predictive value for language development varies with age at implantation. These observations are considered in the context of an epigenetic model in which dynamic genomic expression can modulate aspects of auditory learning, offering insights into factors that can influence a child's acquisition of spoken language after cochlear implantation. Increased understanding of these interactions could lead to targeted interventions that interact with the epigenome to influence language outcomes with intervention, particularly in periods in which development is subject to time-sensitive experience.

Current state of knowledge: implications for developmental research--key issues.

This is the final article in a series of five review articles and one editorial that summarizes the proceedings of the National Institute on Deafness and Other Communication Disorders workshop on Outcomes Research in Children with Hearing Loss held December 12 and 13, 2006. The purpose of this article is to highlight the recommendations that emerged during the workshop, addressing the developmental needs of children with hearing impairment. The information in this summary is based on the National Institute on Deafness and Other Communication Disorders workshop minutes available at http://www.nidcd.nih.gov/funding/programs/hb/outcomes/recommendations.htm. General research issues focus on funding mechanisms, access to a sufficient population, experimental cohorts and control groups, research methods and outcomes, standardization of testing across agencies and intervention programs, and facilitating access to data. Discussion of those issues is followed by an outline that presents future needs in outcomes research, including research design, sources of variance, research needs and gaps, and development of measurement tools.

Ties between the lexicon and grammar: cross-sectional and longitudinal studies of bilingual toddlers.

Studies using the English and Spanish MacArthur Communicative Development Inventories demonstrated that the grammatical abilities of 20-30-month-old bilingual children were related more strongly to same-language vocabulary development than to broader lexical-conceptual development or maturation. First, proportions of different word types in each language varied with same-language vocabulary size. Second, individual changes in predicate and closed class word proportion scores were linked to growth in same-language vocabulary but not to total conceptual vocabulary. Third, increases in English utterance length and English and Spanish sentence complexity were related to growth in same-language vocabulary but not to growth in conceptual vocabulary. Increases in Spanish utterance length were linked to growth in both Spanish vocabulary and conceptual vocabulary. Possible mechanisms underlying these patterns are considered.

Dynamics of Word Comprehension in Infancy: Developments in Timing, Accuracy, and Resistance to Acoustic Degradation.

Online comprehension of naturally spoken and perceptually degraded words was assessed in 95 children ages 12 to 31 months. The time course of word recognition was measured by monitoring eye movements as children looked at pictures while listening to familiar target words presented in unaltered, time-compressed, and low-pass-filtered forms. Success in word recognition varied with age and level of vocabulary development, and with the perceptual integrity of the word. Recognition was best overall for unaltered words, lower for time-compressed words, and significantly lower in low-pass-filtered words. Reaction times were fastest in compressed, followed by unaltered and filtered words. Results showed that children were able to recognize familiar words in challenging conditions and that productive vocabulary size was more sensitive than chronological age as a predictor of children's accuracy and speed in word recognition.