Jana M. Iverson - US grants

This research explores the origins of the link between gesture and speech by focusing on the dynamic properties of the development of infant vocal and motor systems. The study addresses specific hypotheses derived from a model of infant vocal and motor system as coupled oscillators that can mutually entrain one another. To examine the ways in which the relative strength and stability of behaviors in the component systems influence entrainment and lead to developmental changes in the strength and specificity of vocal-motor coordination, vocalizations, rhythmic limb movements, speech, gestures, and vocal- motor and speech-gesture coordinations will be observed in infants biweekly between the ages of 2 and 19 months. Thirty full-term, normally-developing infants will be videotaped at home for 45 minutes in naturalistic and semistructured play contexts. All infant vocalizations, rhythmic limb movements, words, and gestures will be coded. Data analyses will focus on normative and milestone-related developmental change in these phenomena, patterns of co-occurrence between vocal and motor behaviors as a function of age, and the relationship between early communicative milestone achievement and the nature and temporal organization of vocal-motor coordination. This research will also assess individual differences among infants in vocal- manual coordination patterns and their potential relationship to later communication. The fact that variation in gesture use has been shown to relate to communicative delay suggests the possibility that individual variability in early vocal-manual coordination may have diagnostic significance for later communication disorders. Identification of the typical pattern and normal range of variation in early vocal-manual coordination will provide normative information required for future diagnostic research.

[unreadable] DESCRIPTION (provided by applicant): Early initiation of intensive intervention may lead to improved outcomes for children with autism spectrum disorders (ASD); yet there are currently no reliable techniques for diagnosing ASD before the age of two years. This research is designed to identify variations in frequencies of occurrence, delayed onset, and/or atypicalities in vocal, motor, and communicative skills that may index later ASD diagnosis. The approach taken involves describing the development of these skills in infant siblings of older children who have been diagnosed with Autism. Infant Siblings are known to be at elevated risk for ASD and language delay. The goal will be to distinguish prospectively between those Infant Siblings eventually diagnosed with ASD, those eventually diagnosed with Language Delay but not ASD, and those with no apparent atypicalities. One hundred fifty Infant Siblings will be observed longitudinally from ages 5 to 14 months, with follow-up at 18, 24, and 36 months. Audio- and videotaped observations designed to sample behavior in contexts that are consistent across participants, standardized instruments, and parental reports will be employed to study vocalizations, rhythmic limb movements, vocal-motor coordinations, postural and locomotor abilities, gross, fine, and oral-motor skills, words, and gestures. Diagnostic outcomes will be assessed at 36 months with the Autism Diagnostic Observation Schedule, Autism Diagnostic Inventory-Revised, and clinical judgment using DSM-IV criteria. Data from all three subgroups of Infant Siblings will also be compared to parallel data from infants with no known risk for ASD currently being followed as part of separate NAAR and NIH-funded studies. Analyses will focus on identifying behavioral markers in infancy that predict a later diagnosis of ASD, assessing their positive predictive value, sensitivity, and specificity, and on evaluating a set of hypotheses concerning variation in patterns of production and developmental trajectories of infant vocal, motor, and communicative behaviors that may differentiate groups and predict an eventual ASD or Language Delay diagnosis. We currently lack reliable methods for diagnosing autism spectrum disorders (ASD) in children younger than 2 years of age. To identify possible predictors of later ASD diagnosis, this study will focus on the development of vocal, motor, and communicative skills in infants at particular risk for ASD and relate atypicalities in infant development to diagnostic status at 3 years of age. [unreadable] [unreadable] [unreadable]

DESCRIPTION (provided by applicant): Although deficits in social communication are considered primary in autism spectrum disorders (ASD), recent evidence suggests that motor impairments also constitute a prominent component of the ASD behavioral profile. Interest in the identification of behavioral markers of ASD in infancy has recently led to a number of prospective, longitudinal studies of infants known to be at elevated risk for ASD and other developmental delays (High-Risk infants;HR). Despite the growing literature on motor concerns in ASD, relatively little attention has been devoted to the early development of motor skills in HR infants. In addition, there is wide variability in the outcomes of HR infants at age 3, and it is possible that variation in motor ability may be related to individual differences in developmental outcomes in other domains (e.g. social communication, language). This research is designed to examine fine motor and object manipulation skills in HR and comparison infants with no such risk (Low Risk infants;LR) between the ages of 12 and 36 months. The approach taken is innovative because it involves the application of newly-developed, technologically sophisticated sensor technology designed for use in unstructured settings in combination with longitudinal behavioral observation to collect finely detailed information about the organization and quality of children's movements as they perform three motor tasks at varying levels of difficulty. Supplemented by standardized motor assessments, these data will support the analysis of fine motor and object manipulation abilities in a much more subtle and sophisticated fashion than has heretofore been possible. Twenty HR infants already being followed from 5 to 36 months as part of a larger study and 20 LR infants will be observed at home at ages 12, 14, 18, 24, and 36 months as they perform motor tasks that involve reaching for, transporting, and placing an object at a target location. An additional cross-sectional group of 50 children, 10 at each age listed above, will also participate. Kinematic data will be collected via lightweight sensorized wristbands and sensors embedded in the objects. Analyses will focus on overall risk group differences, on change in the kinematic and behavioral variables as a function of task difficulty and age, and on group by difficulty interactions at varying ages. These will be used to evaluate developmental trajectories and possible developmental delays and impairments in the motor skill of HR children, to examine the relation between motor skills and delays exhibited by HR children in other developmental domains, and to provide preliminary information about kinematic and behavioral signatures that may be related to an eventual diagnosis of ASD. PUBLIC HEALTH RELEVANCE: The recent rapid increase in diagnosis of Autism Spectrum Disorders makes it imperative that we learn more about the early development of children at high risk for ASD. Because motor impairments are common in older children with ASD, and because infants at risk for ASD often exhibit early motor delays, the research will focus on the early development of motor skills in at-risk infants and relate this information to later developmental outcomes. To do this, a novel movement measurement technology will be employed together with detailed behavioral observations of at-risk and comparison low-risk children as they engage in a series of naturalistic motor tasks between the ages of 12 and 36 months.

DESCRIPTION (provided by applicant): Over the course of the first year, typically-developing infants rapidly acquire skills in object-directed reaching and postural control. These skills underlie increasingly sophisticated object exploration behaviors that yield information not only about objects in the world but about the effects of the infant's own actions on those objects. Object exploration and the knowledge that it generates is, in turn, foundational for the later development of language and communication. This suggests that the emergence of reaching and the progressive achievement of greater postural control, mediated by object exploration, may have cascading and far-reaching effects on later development, not only on more advanced motor planning skills, but in domains such as communication and language that are not typically conceived as being influenced by early motor development. Conversely, delays and impairments in reaching and postural development may negatively impact object exploration and, therefore, the eventual development of later, higher-order developments in motor planning, language, and communication. The work proposed in this application is designed to shed light on these previously unexplored developmental pathways by providing systematic longitudinal data on the emergence of reaching, the growth of postural control, changes in object exploration behaviors, and later developments in motor planning, language, and communication from 2.5 to 36 months of age. The research is innovative because it employs a dense, longitudinal home-visit observation schedule and combines behavioral and kinematic data to permit close tracking of advances in reaching, self-sitting and object exploration. This multi-method approach will support a detailed examination of normative and atypical developmental trajectories in these domains and their relationship to the development of later-emerging behaviors both within and across domains of development. By focusing not only on typically-developing, low-risk (LR) infants but also on infants known to be at heightened risk (HR) for communicative delays (viz., infants with an older brother or sister diagnosed with Autistic Disorder), we will be able to assess early patterns of delay and examine any negative cascading effects that they may have This, in turn, will lay the groundwork for improvements in clinical practice and design of interventions to remediate early delays and avoid their cascading effects. Successful completion of this project will result in: a) clarification of the nature of the relationship between the growh of postural control, the development of infant reaching, and improvement in object exploration skills during the first year; b) specification of the nature and extent of delays and impairments i postural control, reaching, and object exploration in HR infants; and c) identification of any predictive relations existing between early postural and motor development and later, higher-order motor, language, and communication skills as mediated by the growth of object exploration.

Summary Symptoms of Autism Spectrum Disorder (ASD) extend beyond the traditional diagnostic triad of social cognition deficits, communication impairments, and limited interests / repetitive behaviors. Converging evidence supports the presence of motor abnormalities in the domain of postural control, including balance and gait. The understanding of these impairments is limited. The long-term goal of our team is to identify mechanisms underlying motor and postural impairments in ASD to further the understanding of the bases of ASD. The proposed project represents an initial step in a program of research designed to identify potential mechanisms underlying motor and postural impairments in ASD. More specifically, here we focus on links between postural/locomotor control and cognition (specifically the top-down regulation of access to the limited process of action control, or `attention for action') in ASD. Our main hypothesis is that postural control difficulties in ASD are due to problems in attention-related processes, which then elicit action control that transiently inhibits action, slowing appropriate postural adjustment. We will test this hypothesis by using dual-task paradigms that combine information-processing (IP) tasks and challenging posture/locomotor tasks. These tasks add an additional requirement for action and thus probe the capacity of the action control process. Thirty young adults diagnosed with ASD (21-45 years old) and 30 age-, gender- and IQ- matched controls will be tested. The dual-task paradigms will include IP tasks (simple and choice reaction time tasks) concurrently presented with standing and walking tasks requiring sensorimotor re-weighting. Simple reaction time tasks minimally challenge action control, while choice reaction time tasks probe decision-making between alternative actions, thus challenging action control more than simple reaction time tasks. Potential findings of the proposed project will enhance our understanding of the etiology of motor impairments and functional consequences of balance difficulties in ASD, both of which may contribute to the development of novel and more effective therapeutic approaches.

PROJECT SUMMARY The onset of walking and growth in social communication and language are likely to be intimately connected. Advances in walking facilitate infants? exploration of the environment and lead to alterations in caregiver input; and these changes in turn provide expanded opportunities for the development of social communication and language. Relative to crawlers, walkers have greater access to distal objects, explore the environment more efficiently, move more with objects in hand, initiate social interaction more easily, and carry objects to caregivers in communicative bids creating moments of shared attention during which caregiver language input is likely to be maximally effective. Delays in the emergence and development of walking may therefore reduce opportunities for exploration and social interaction and diminish rich caregiver input beneficial for the growth of social communication and language. The purpose of this research is to conduct a detailed examination of this unstudied developmental pathway by providing prospective, longitudinal data on the emergence and development of walking, changes in locomotor exploration, advances in infant communication, alterations in caregiver communicative input, and later developments in language from 6 to 36 months of age. The study design involves intensive longitudinal observations that combine standard gait data with a rich array of infant motor, exploration, and communicative behaviors and caregiver input to be coded from video. This will permit close tracking of advances in walking, locomotor exploration, and infant and caregiver communication and evaluation of their relationship to later child language outcomes. By comparing infants known to be at heightened risk (HR) for motor and communicative delays (viz., infants with an older sibling diagnosed with Autism Spectrum Disorder) to infants with no known risk (low-risk infants, LR), this research will yield a wealth of data not only on fundamental developmental processes but on the effects of developmental delays during a critical period in development. It will also yield a deeper understanding of the ways in which infant exploration and communication and caregiver input change when infants begin to walk, and thus it will lay the groundwork for the development of novel interventions that can be delivered early with the goal of enhancing social communication and language outcomes in infants with early motor delays with a broad range of etiologies. !