Toddler Talk Project
Characterizing Early Language Development in Children Diagnosed with an Autism Spectrum Disorder (ASD)
This project investigates the empirical overlap recently demonstrated between the language impairments observed within the autism spectrum and those observed outside it in other language specific disorders. Delays in language development and impairments in communication ability constitute a diagnostic feature of Autistic Disorder and PDD-NOS/Atypical Autism; communication challenges are also well documented among children with Asperger’s Disorder. Thus, the motivation of this study is to determine whether the language impairments observed in Autism Spectrum Disorder (ASD) involve a unique constellation of phenomena (the distinct category account), or whether they differ only quantitatively from those observed in language-specific disorders (the dimensional account). The first specific objective will evaluate the early language skills of a large sample of children on the autism spectrum at age 2;6; a comparable objective will evaluate language outcomes by assessing the same children at age 5;6. Further objectives will compare longitudinally two autism spectrum subgroups with two recently collected samples – one of late talkers with specific language delay and one of typically developing young children – who received the same assessments as those proposed for the participants on the autism spectrum. This longitudinal comparison will utilize a series of group design experimental studies to examine mechanisms and patterns of novel word learning, the link between lexical and grammatical skills, and the relation between early language abilities and verbal repetition. Findings from this project will significantly advance the understanding of the nature of early language development in ASD, will lead to more accurate early diagnosis by clarifying the boundaries between late talkers with and without ASD, and will provide more refined language phenotypes that should direct better fitting treatment approaches.
Language Processes Lab in the news:
"New Project Could Help Predict Autism in Children Earlier: A new project at the Waisman Center in Madison is offering families the chance to have a professional diagnosis for autism in children much earlier than ever before." Madison Channel 3 News reports. - April 19, 2007.
Early Language Learning Project
The Early Language Learning Project (conducted in collaboration with Dr. Julia Evans and Dr. Robin Chapman) is focused on examining linguistic processing abilities of toddlers with late onset of language development compared to those with typical patterns of language acquisition. In this longitudinal project we are investigating variables that predict language outcomes at kindergarten and assessing links between early limitations in linguistic processing capacity and subsequent diagnosis of SLI. This project is funded by the National Institutes of Health (NIDCD). Supplemental funding for this project has also supported an investigation of dialectal characteristics of African American toddlers, based on spontaneous language samples, such that typical dialect usage can ultimately be compared to patterns observed in early language delay.
Project Outcomes:
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The MacArthur Communicative Development Inventory (MCDI), a parent report measure of early vocabulary and grammar skills, was found to be useful in characterizing the language skills of late-talking toddlers with specific language delay when compared to other language assessment tests administered directly to the child.
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At 2 1/2 years, late talkers were less likely that a group of younger children with the same vocabulary level (16-month-olds) to combine words into short 'sentences.' This suggests that late talkers have delayed onset of sentence structure development with the same vocabulary building blocks as the younger children with age-expected language skills.
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On the "picnic task" which focused on the ability to learn new words at 2 1/2 years of age, late talkers were significantly poorer than typical talkers at producing novel words. Further, toddlers with typical language skills seemed to be sensitive to the resemblance of novel words to real words, but late talkers as a group were not.
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Toddlers' ability to learn new words on the picnic task at 2 1/2 years was a predictor of their grammatical skills at 3 1/2 years of age.
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At 2 1/2 years, there are few differences in the production of non-standard forms (e.g., "He go home" for "He is going home") by toddlers from Standard American English (SAE) and African American English (AAE) speaking backgrounds. However, by 3 1/2 years of age these toddlers differ in the number and frequency of non-standard forms produces and adult listeners who are familiar with both dialects can distinguish between child speakers from these different linguistic backgrounds.
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Over time, children identified as late talkers had similar patterns of growth in vocabulary and grammar as children without language delays, even though the late talkers had reduced levels of skills. These late talkers formed two distinct groups based on vocabulary and grammar skills: one group who caught up to the group of children with typical language skills ("late bloomers") and one group who continued to show delays.
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The vast majority of late-talking toddlers had good language outcomes at kindergarten. Only 10% displayed language problems that qualified them for a clinical diagnosis of language impairment at 5 1/2 years of age. As a group, however, those children who had initially been late talkers continued to be less highly skilled in language areas at kindergarten age than children with typical early developmental profiles.
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Three measurements given at 2 1/2 years which examine language production (MCDI, Preschool Language Scale-3, and picnic task) significantly predicted expressive language abilities at 5 1/5 years. The combined use of these three measures may be helpful clinically to predict which toddlers with language delay are likely to catch up on their own and which are likely to have persistent language problems.
Midwest Collaboration on SLI
Susan Ellis Weismer is an investigator on the Midwest Collaboration on Specific Language Impairment, an NIH-funded clinical research center (P50 grant) directed by J. Bruce Tomblin at the University of Iowa. The clinical research center consists of a group of researchers from various universities who are conducting an epidemiologic, longitudinal investigation of language impairment in school-age children and adolescents. This research currently focuses on working memory and language processing skills in adolescents with spoken language disorders and reading disabilities.
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Project 2: Processing Abilities in Children with Specific Language Impairment
This investigation involves a continuation of a longitudinal, epidemiologic study of developmental language impairment, the Midwest Collaboration on Child Language Impairment (Director: J.B. Tomblin, University of Iowa). The aim of this subcontract for Project 2 is to evaluate a limited processing capacity account of oral language impairment in adolescents who have a history of specific language impairment (SLI). Performance on various processing measures is being assessed in 8th and 10th grades for children with typical spoken language abilities, specific language impairment (SLI) and nonspecific language impairment (NLI). Data from these same children during the elementary school period is being used to determine the stability of processing abilities and the degree to which the children's earlier performance on processing tasks predicts later language abilities. A new direction of research that has been undertaken in this project entails a functional neuroimaging study; findings from this study are being used, along with behavioral data, to more thoroughly assess the claim that processing capacity limitations play a role in developmental language disorder.
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Project 3: Processing Abilities in Children with Reading Disabilities
The aim of this subcontract for Project 3 is to evaluate the role of limitations in processing capacity in children with reading disabilities by examining the relation between working memory capacity, oral language processing, and reading abilities. Performance on various linguistic and spatial working memory measures is being assessed in 8th and 10th grades for poor readers and good readers, with children with reading comprehension deficits being considered separately from those with decoding difficulties. Data from these same children during the elementary school period will be used to determine the degree to which the children's earlier performance on processing tasks can predict later reading abilities.
