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Upcoming Workshop
The Neurocognition of
Developmental Language Disorders
A CBBC Workshop
Abstracts
Funder Presentation NIDCD Funding Opportunities in Childhood Language Disorders Judith Cooper
NIDCD, NIH
Bethesda, MarylandAn overview of currently NIDCD-funded research in language, and specifically on language disorders in children, will be provided. In addition, recent relevant initiatives will be discussed. The type of research, and research foci, for which investigators might seek NIDCD funding will be presented.
Research Presentations Timing Matters Writ Large and Small: Toward a Neuroscience of Disorders of Linguistic Growth
University of Kansas
Lawrence, KansasLanguage acquisition is guided by mechanisms of change. Models of language impairment focus on possible breakdowns in these mechanisms, with putative etiological sources including highly specified linguistic operations, genetics, brain functioning, perceptual processing, cognitive disabilities, and learning algorithms, among others. At the same time, there is emerging evidence of striking parallels in the ways in which children with Specific Language Impairment (SLI) acquire language as compared to their unaffected peers. The full picture includes robust mechanisms as well as selective weaknesses. The evidence ranges from growth/timing mechanisms writ large, in the form of growth trajectories over months and years, to growth writ small, in the form of detailed linguistic error analyses, and even smaller, in the timing of ERP responses within clauses. This talk will review the evidence and lay out some key dimensions in capturing the similarities and differences, across different linguistic domains. It will conclude with a call for updated maturational models as a way to link genetic, neurological, and behavioral growth/timing phenomena that drive language acquisition in children with and without language impairments.
FOXP2, the KE Family and the Development of Speech and Language
UCL Institute of Child Health, University College London, and Great Ormond Street Hospital for Children
London, United KingdomThe 'core' deficit in the affected KE family members is an orofacial and verbal dyspraxia. This suggests an underlying impairment in the rapid selection and accurate sequencing of orofacial movements that are most evident in speech. Structural neuroimaging in the affected members revealed bilateral abnormalities in a number of motor, and speech and language-related brain regions. Functional neuroimaging during verb generation and repetition tasks disclosed a distinctly atypical pattern of activation, viz. diffuse, bilateral, and located predominantly in posterior cortical regions. Direct comparison between affected and unaffected family members indicated that the FOXP2 mutation is associated with significant underactivation in several regions that had been found to be morphologically abnormal, including Broca's area as well as the inferior frontal gyrus and putamen on the right. Together, these structural and functional MR results provide a coherent explanation for the affected members' striking and persistent disorder. The neuropsychological and neuroimaging findings will be related to the genetic basis of the disorder in the KE family, and to the pattern of gene expression during embryological development in humans and in mice. The convergence of data from the behavioural, neuroimaging, and gene expression studies lead to a tentative model of the neuroanatomy of the speech and language system.
Procedural memory in Developmental Language Impairment
Georgetown University
Washington, DCSpecific Language Impairment (SLI) has generally been explained by either of two broad classes of hypotheses, which posit either a deficit specific to grammar, or a largely non-linguistic processing impairment. Here we explore an alternative perspective. We suggest that SLI may be largely explained by the abnormal development of brain structures that constitute the procedural memory system. This system, which is composed of a network of inter-connected structures rooted in frontal/basal-ganglia circuits, subserves the learning and execution of motor and cognitive skills, and may be specialized for sequences and rules. Evidence has also implicated procedural memory in aspects of grammar. According to the Procedural Deficit Hypothesis, a significant proportion of individuals with SLI suffer from abnormalities of this brain network, leading to impairments of the linguistic and non-linguistic functions that depend on it. In contrast, functions such as lexical and declarative memory, which depend largely on other brain structures, are expected to remain essentially spared. We suggest that the neurocognitive data — from behavioral, Event-Related Potential, functional neuroimaging, and anatomical studies — are consistent with this perspective, and moreover suggest that lexical and declarative memory play an important compensatory role. Broader implications and issues are discussed, including an examination of the co-occurrences and similarities among SLI, autism, dyslexia, and ADHD.
Examination of the Role of Working Memory Limitations in Specific Language Impairment
University of Wisconsin-Madison
Madison, WisconsinChildren with specific language impairment (SLI) have been characterized as having 'limited processing capacity.' Within different theoretical accounts, processing limitations in SLI have been conceptualized as deficits in auditory/temporal processing, generalized speed of processing, executive function, phonological storage, or working memory. This talk will primarily focus on evidence for the role of working memory limitations in SLI. Data will be presented from a large cohort of school-age children and adolescents who were participants in an epidemiologic, longitudinal investigation of language impairment (Collaboration on Specific Language Impairment). This sample includes children with a wide range of profiles with respect to nonverbal cognition and language abilities. The role of processing limitations will be considered from the perspective of both group and individual differences. Results indicate that individuals with SLI, as a group, display deficits on a variety of verbal working memory tasks that are apparent even when extant language skills are taken into account or clinical language difficulties have resolved. Working memory is an important predictor of later language abilities. Performance on verbal working memory tasks at second grade is a significant, unique predictor of overall language outcomes at tenth grade. Additionally, deficits on a spatial working memory task provide evidence for domain-general working memory limitations in SLI. Although the group findings of working memory deficits are robust and compelling, it is also critical to note that not every child with SLI exhibits working memory problems and that limitations in other cognitive processes have also been implicated in SLI. Findings from these studies and prior research in the literature will be interpreted relative to the Interactive-Multiple Path Account of SLI. Support for this work was provided by the National Institute on Deafness and Other Communicative Disorders and the National Institute of Child Health and Human Development.
Neurophysiological Markers of Developmental Language Impairment
Max Planck Institute for Human Cognitive and Brain Sciences
Leipzig, GermanyOver the past years the neurophysiological markers of the stages of normal language development have been described with respect to phonological, lexical-semantic and syntactic processes. Against the background of these data, event-related brain potential findings on the processing of phonological, lexical-semantic and syntactic processes in infants with a familial risk for SLI and children with a test-defined risk for SLI and their age-matched controls will be presented. Data from a longitudinal study allowed us to conduct predictive and retrospective analyses and thereby to establish links between the brain's reaction to language input during the first months of life and the language behavior measured later during development. These analyses suggest that for those children that are diagnosed with SLI during childhood, atypical (non-typical) event-related brain responses to particular aspects of phonologically relevant acoustic parameters are already apparent by the age of 2 months. The implications of this finding with respect to the deficit underlying SLI are discussed.
Phonological and Speech Processing Deficits in Developmental Dyslexia and Specific Language Impairment
Amy S. Desroches
The University of Western Ontario
London, Ontario, CanadaIt has been suggested that language difficulties in specific language impairment (SLI) can be traced to problems with speech processing. This hypothesis bears a remarkable resemblance to an earlier hypothesis concerning reading deficits in dyslexia — that a phonological impairment in these children leads to reading difficulties. On the other hand, relatively few studies have examined both groups in parallel with respect to reading, language and phonological processing. We present data from a range of behavioral and event-related potential (ERP) studies that directly assesses the extent of phonology and speech perception difficulties in children with either reading or language impairment, or both. Our data reveal many important similarities in dyslexia and SLI. However, we also present data indicating some divergence between these groups, in particular with respect to the finding that speech perception deficits are much more likely to be observed in language impaired children. Moreover, we observe little difference in the degree of phonological processing deficits in the two groups, which seems to defy the hypothesis that the two differ only with respect of degree of impairment. We believe our data do support a processing deficit view of both disorders, and we present evidence from connectionist modeling that might help demonstrate how processing deficits lead to reading and language difficulties. On the other hand, we also suggest that the exact nature of the processing deficit differs in the two populations, leading to slightly different problems with reading, speech perception and language.