Functional near-infrared spectroscopy in toddlers: Neural differentiation of communicative cues and relation to future language abilities.

The toddler and preschool years are a time of significant development in both expressive and receptive communication abilities. However, little is known about the neurobiological underpinnings of language development during this period, likely due to difficulties acquiring functional neuroimaging data. Functional near-infrared spectroscopy (fNIRS) is a motion-tolerant neuroimaging technique that assesses cortical brain activity and can be used in very young children. Here, we use fNIRS during perception of communicative and noncommunicative speech and gestures in typically developing 2- and 3-year-olds (Study 1, n = 15, n = 12 respectively) and in a sample of 2-year-olds with both fNIRS data collected at age 2 and language outcome data at age 3 (Study 2, n = 18). In Study 1, 2- and 3-year-olds differentiated between communicative and noncommunicative stimuli as well as between speech and gestures in the left lateral frontal region. However, 2-year-olds showed different patterns of activation from 3-year-olds in right medial frontal regions. In Study 2, which included two toddlers identified with early language delays along with 16 typically developing toddlers, neural differentiation of communicative stimuli in the right medial frontal region at age 2 predicted receptive language at age 3. Specifically, after accounting for variance related to verbal ability at age 2, increased neural activation for communicative gestures (vs. both communicative speech and noncommunicative gestures) at age 2 predicted higher receptive language scores at age 3. These results are discussed in the context of the underlying mechanisms of toddler language development and use of fNIRS in prediction of language outcomes.

SOCIOEMOTIONAL AND BEHAVIORAL PROBLEMS IN TODDLERS WITH LANGUAGE DELAY.

Toddlers with language delay are at risk for persistent developmental and behavioral difficulties; however, the association between socioemotional/behavior problems and language in young children is not well understood. This study explored socioemotional/behavior problems in a unique sample of toddlers with language delays using a measure developed explicitly for this age group. Toddlers identified by 18 months with receptive and expressive language delay (LD; n = 30) or typical development (TD; n = 61) were evaluated at 18 and 24 months of age using the Infant-Toddler Social and Emotional Assessment (ITSEA) and the Mullen Scales of Early Learning. Compared to toddlers who had TD, toddlers with LD had significantly more concerning scores at 18 and 24 months on all ITSEA domains. The rate of "clinical concern" on most domains was not high in either group, except that >60% of LD toddlers were in the clinical concern range on the Competence domain. Socioemotional/behavioral problems were dimensionally related to receptive and expressive language, with greater language delay associated with more concerning ITSEA scores. Socioemotional and behavioral problems are related to receptive and expressive language abilities in 18- and 24-month-olds, indicating the need for screening of both types of concerns in toddlers identified with potential language delays.

Modelling gesture use and early language development in autism spectrum disorder.

BACKGROUND: Nonverbal communication abilities, including gesture use, are impaired in autism spectrum disorder (ASD). However, little is known about how common gestures may influence or be influenced by other areas of development. AIMS: To examine the relationships between gesture, fine motor and language in young children with ASD compared with a comparison group using multiple measures and methods in a structural equation modelling framework. METHODS & PROCEDURES: Participants included 110 children with ASD and a non-ASD comparison group of 87 children (that included children with developmental delays (DD) or typical development (TD)), from 12 to 48 months of age. A construct of gesture use as measured by the Communication and Symbolic Behavior Scales-Developmental Profile Caregiver Questionnaire (CQ) and the Autism Diagnostic Observation Schedule (ADOS), as well as fine motor from the Mullen Scales of Early Learning and Vineland Adaptive Behavior Scales-II (VABS-II) was examined using second-order confirmatory factor analysis (CFA). A series of structural equation models then examined concurrent relationships between the aforementioned latent gesture construct and expressive and receptive language. A series of hierarchical regression analyses was run in a subsample of 36 children with ASD with longitudinal data to determine how gesture factor scores predicted later language outcomes. OUTCOMES & RESULTS: Across study groups, the gesture CFA model with indicators of gesture use from both the CQ (parent-reported) and ADOS (direct observation), and measures of fine motor provided good fit with all indicators significantly and strongly loading onto one gesture factor. This model of gesture use, controlling for age, was found to correlate strongly with concurrent expressive and receptive language. The correlations between gestures and concurrent language were similar in magnitude in both the ASD and non-ASD groups. In the longitudinal subsample of children with ASD, gestures at time 1 predicted later receptive (but not expressive) language outcomes on the VABS-II, after controlling for nonverbal cognition, ASD severity, age and time 1 language. CONCLUSIONS & IMPLICATIONS: This study extends research on the relationship between nonverbal communication and language by supporting the idea of an underlying construct of gesture use that includes fine motor ability and relates to language in young children with ASD. This further supports theories espousing developmental influences of motor and nonverbal communication strategies as important in early language learning.

Longitudinal study of symptom severity and language in minimally verbal children with autism.

BACKGROUND: A significant minority of children with autism spectrum disorder (ASD) are considered 'minimally verbal' due to language development stagnating at a few words. Recent developments allow for the severity of ASD symptoms to be examined using Autism Diagnostic Observation Schedule (ADOS) Social Affect (SA) and Restricted and Repetitive Behaviors (RRB) domain severity scores. The aim of the current study was to explore language outcomes in a cohort of minimally verbal children with autism evaluated through the preschool years and determine if and how ASD symptom severity in core domains predicts the development of spoken language by age 5. METHODS: The sample consisted of 70 children with autism aged 1-5 years at the first evaluation who were examined at least 1 year later, during their fifth year of age. The ADOS overall level of language item was used to categorize children as minimally verbal or having phrase speech, and the Mullen Scales of Early Learning was used as a continuous measure of expressive language. RESULTS: At Time 1, 65% (n = 47) of children in the sample were minimally verbal and by Time 2, 36% (n = 17 of 47) of them had developed phrase speech. While the Time 1 ADOS calibrated severity scores did not predict whether or not a child remained minimally verbal at Time 2, change in the SA calibrated severity score (but not RRB) was predictive of the continuous measure of expressive language. However, change in SA severity no longer predicted continuous expressive language when nonverbal cognitive ability was added to the model. CONCLUSIONS: Findings indicate that the severity of SA symptoms has some relationship with continuous language outcome, but not categorical. However, the omnipresent influence of nonverbal cognitive ability was confirmed in the current study, as the addition of it to the model rendered null the predictive utility of SA severity.

Early diagnosis of autism spectrum disorder: stability and change in clinical diagnosis and symptom presentation.

BACKGROUND: Although a diagnosis of autism spectrum disorder (ASD) appears to be stable in children as young as age three, few studies have explored stability of a diagnosis in younger children. Predictive value of diagnostic tools for toddlers and patterns of symptom change are important considerations for clinicians making early diagnoses. Most findings come from high-risk samples, but reports on children screened in community settings are also needed. METHODS: Stability of diagnosis and Autism Diagnostic Observation Schedule ­ Toddler Module (ADOS-T) classifications and scores was examined across two time points in a sample of 82 children identified through the FIRST WORDS Project.Children received two comprehensive diagnostic evaluations at average ages of 19.39 (SD = 2.12) and 36.89 (SD = 3.85) months. RESULTS: Stability was 100% when confirming and ruling out a diagnosis of ASD based on a comprehensive diagnostic evaluation that included clinic and home observations,although diagnosis was initially deferred for 17% of the sample. Receiver Operating Characteristic curves revealed excellent sensitivity and acceptable specificity for the ADOS-T compared to concurrent diagnosis. Logistic regressions indicated good predictive value of initial ADOS-T scores for follow-up diagnosis. Finally, both ASD and Non-ASD children demonstrated a decrease in Social Affect scores (i.e.,improvement), whereas children with ASD demonstrated an increase in Restricted and Repetitive Behavior scores (i.e., worsening), changes that were accounted for by nonverbal developmental level in mixed model analyses. CONCLUSIONS: Short-term stability was documented for children diagnosed at 19 months on average, although a minority of children initially showed unclear diagnostic presentations.Findings highlight utility of the ADOS-T in making early diagnoses and predicting follow-up diagnoses. Children with ASD demonstrated improvement in social communication behaviors and unfolding of repetitive behaviors, suggesting that certain early patterns of change in symptoms may be characteristic of ASD. KEYWORDS: Autism spectrum disorder, developmental delay, diagnosis, development,assessment.

Classifying and characterizing the development of adaptive behavior in a naturalistic longitudinal study of young children with autism.

BACKGROUND: Adaptive behavior, or the ability to function independently in ones' environment, is a key phenotypic construct in autism spectrum disorder (ASD). Few studies of the development of adaptive behavior during preschool to school-age are available, though existing data demonstrate that the degree of ability and impairment associated with ASD, and how it manifests over time, is heterogeneous. Growth mixture models are a statistical technique that can help parse this heterogeneity in trajectories. METHODS: Data from an accelerated longitudinal natural history study (n = 105 children with ASD) were subjected to growth mixture model analysis. Children were assessed up to four times between the ages of 3 to 7.99 years. RESULTS: The best fitting model comprised two classes of trajectory on the Adaptive Behavior Composite score of the Vineland Adaptive Behavior Scale, Second Edition-a low and decreasing trajectory (73% of the sample) and a moderate and stable class (27%). CONCLUSIONS: These results partially replicate the classes observed in a previous study of a similarly characterized sample, suggesting that developmental trajectory may indeed serve as a phenotype. Further, the ability to predict which trajectory a child is likely to follow will be useful in planning for clinical trials.

Trajectories of cognitive development in toddlers with language delays.

BACKGROUND: Toddlers with early language delays (LD) are at risk for developmental difficulties, including autism spectrum disorder (ASD). However, little is known about early cognitive skill acquisition in this population. AIMS: To explore heterogeneity in cognitive development in toddlers with significant LD (n = 30) or typical development (n = 61), and how this relates to 36-month outcomes (ASD, non-ASD delays, or no delays). METHODS: Growth mixture modeling of nonverbal and verbal mental age (NVMA, VMA) scores from the Mullen Scales of Early Learning was conducted with data from 18, 24 and 36 months. RESULTS: A two-class NVMA solution was selected (Age Appropriate, 82%, Delayed, 18%); class membership was related to the no delay outcome, and although the proportion of toddlers with ASD in the Age-Expected class was 17% compared to 50% of toddlers with non-ASD delays, this difference was not statistically significant. The best-fitting model for VMA included three classes: Age Appropriate (66%), Delay Catch-Up (23%), Delayed (11%); class assignment differed by outcome. Children in the Delay Catch-Up class were more likely to have non-ASD delays compared to ASD, while the reverse was true in the Delayed class. CONCLUSIONS: Cognitive development in toddlers with LD is heterogeneous, and delayed verbal trajectories relate to later ASD diagnosis.

Prefrontal Hemodynamics in Toddlers at Rest: A Pilot Study of Developmental Variability.

Functional near infrared spectroscopy (fNIRS) is a non-invasive functional neuroimaging modality. Although, it is amenable to use in infants and young children, there is a lack of fNIRS research within the toddler age range. In this study, we used fNIRS to measure cerebral hemodynamics in the prefrontal cortex (PFC) in 18-36 months old toddlers (n = 29) as part of a longitudinal study that enrolled typically-developing toddlers as well as those "at risk" for language and other delays based on presence of early language delays. In these toddlers, we explored two hemodynamic response indices during periods of rest during which time audiovisual children's programming was presented. First, we investigate Lateralization Index, based on differences in oxy-hemoglobin saturation from left and right prefrontal cortex. Then, we measure oxygenation variability (OV) index, based on variability in oxygen saturation at frequencies attributed to cerebral autoregulation. Preliminary findings show that lower cognitive (including language) abilities are associated with fNIRS measures of both lower OV index and more extreme Lateralization index values. These preliminary findings show the feasibility of using fNIRS in toddlers, including those at risk for developmental delay, and lay the groundwork for future studies.

Convergent and divergent validity of the Mullen Scales of Early Learning in young children with and without autism spectrum disorder.

The purpose of this study was to report on the construct, convergent, and divergent validity of the Mullen Scales of Early Learning (MSEL), a widely used test of development for young children. The sample consisted of 399 children with a mean age of 3.38 years (SD = 1.14) divided into a group of children with autism spectrum disorder (ASD) and a group of children not on the autism spectrum, with and without developmental delays. The study used the MSEL and several other measures assessing constructs relevant to the age range--including developmental skills, autism symptoms, and psychopathology symptoms--across multiple methods of assessment. Multiple-group confirmatory factor analyses revealed good overall fit and equal form of the MSEL 1-factor model across the ASD and nonspectrum groups, supporting the construct validity of the MSEL. However, neither full nor partial invariance of factor loadings was established because of the lower loadings in the ASD group compared with the nonspectrum group. Exploratory structural equation modeling revealed that other measures of developmental skills loaded together with the MSEL domain scores on a Developmental Functioning factor, supporting convergent validity of the MSEL. Divergent validity was supported by the lack of loading of MSEL domain scores on Autism Symptoms or Emotion/Behavior Problems factors. Although factor structure and loadings varied across groups, convergent and divergent validity findings were similar in the ASD and nonspectrum samples. Together, these results demonstrate evidence for the construct, convergent, and divergent validity of the MSEL using powerful data-analytic techniques.

Social (pragmatic) communication disorder: a research review of this new DSM-5 diagnostic category.

Social (pragmatic) communication disorder (SCD) is a new diagnostic category in the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5). The purpose of this review is to describe and synthesize the relevant literature from language and autism spectrum disorder (ASD) research relating to pragmatic language impairment and other previously used terms that relate to SCD. The long-standing debate regarding how social communication/pragmatic impairments overlap and/or differ from language impairments, ASD, and other neurodevelopmental disorders is examined. The possible impact of the addition of SCD diagnostic category and directions for future research are also discussed.

Comparison of DSM-IV and DSM-5 factor structure models for toddlers with autism spectrum disorder.

OBJECTIVE: The present study examined the factor structure of autism symptoms in toddlers, to aid understanding of the phenotype during the developmental period that represents the earliest manifestations of autism symptoms. This endeavor is particularly timely, given changes in symptom structure from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) to the recently released Fifth Edition (DSM-5). METHOD: Factor structure was examined in a sample of toddlers between 12 and 30 months of age (mean = 20.37 months, SD = 3.32 months) diagnosed with autism spectrum disorder (ASD) and recruited from community settings or referred for evaluation (N = 237). Confirmatory factor analyses were conducted comparing the relative fit of 4 distinct, previously proposed and validated models: DSM-5, DSM-IV, 1-factor, and an alternative 3-factor model proposed by van Lang et al. RESULTS: Findings revealed that the 1-factor model provided the poorest fit, followed by the DSM-IV model and the van Lang et al. model. The DSM-5 model provided the best fit to the data relative to other models and good absolute fit. Indicators for the confirmatory factor analyses, drawn from the Autism Diagnostic Observation Schedule-Toddler Module (ADOS-T), loaded strongly onto the DSM-5 Social Communication and Social Interaction factor and more variably onto the DSM-5 Restricted/Repetitive Language and Behavior factor. CONCLUSIONS: Results indicate that autism symptoms in toddlers, as measured by the ADOS-T, are separable and best deconstructed into the 2-factor DSM-5 structure, supporting the reorganization of symptoms in the DSM-5. Consistency of the present results in toddlers with previous studies in older children and adults suggests that the structure of autism symptoms may be similar throughout development.