Meghan R. Swanson

Early brain development in infants at high risk for autism spectrum disorder

Brain enlargement has been observed in children with autism spectrum disorder (ASD), but the timing of this phenomenon, and the relationship between ASD and the appearance of behavioural symptoms, are unknown. Retrospective head circumference and longitudinal brain volume studies of two-year olds followed up at four years of age have provided evidence that increased brain volume may emerge early in development. Studies of infants at high familial risk of autism can provide insight into the early development of autism and have shown that characteristic social deficits in ASD emerge during the latter part of the first and in the second year of life. These observations suggest that prospective brain-imaging studies of infants at high familial risk of ASD might identify early postnatal changes in brain volume that occur before an ASD diagnosis. In this prospective neuroimaging study of 106 infants at high familial risk of ASD and 42 low-risk infants, we show that hyperexpansion of the cortical surface area between 6 and 12 months of age precedes brain volume overgrowth observed between 12 and 24 months in 15 high-risk infants who were diagnosed with autism at 24 months. Brain volume overgrowth was linked to the emergence and severity of autistic social deficits. A deep-learning algorithm that primarily uses surface area information from magnetic resonance imaging of the brain of 6–12-month-old individuals predicted the diagnosis of autism in individual high-risk children at 24 months (with a positive predictive value of 81% and a sensitivity of 88%). These findings demonstrate that early brain changes occur during the period in which autistic behaviours are first emerging.

Randomized controlled trial of parental responsiveness intervention for toddlers at high risk for autism.

This study tested the effects of a parent-mediated intervention on parental responsiveness with their toddlers at high risk for an autism spectrum disorder (ASD). Participants included caregivers and their 66 toddlers at high risk for ASD. Caregivers were randomized to 12 sessions of an individualized parent education intervention aimed at improving parental responsiveness or to a monitoring control group involving 4 sessions of behavioral support. Parental responsiveness and child outcomes were measured at three time points: at beginning and end of the 3-month treatment and at 12-months post-study entry. Parental responsiveness improved significantly in the treatment group but not the control group. However, parental responsiveness was not fully maintained at follow up. There were no treatment effects on child outcomes of joint attention or language. Children in both groups made significant developmental gains in cognition and language skills over one year. These results support parental responsiveness as an important intervention target given its general association with child outcomes in the extant literature; however, additional supports are likely needed to fully maintain the treatment effect and to affect child outcomes.

Functional neuroimaging of high-risk 6-month-old infants predicts a diagnosis of autism at 24 months of age

Functional brain imaging of 6-month-old infants with a high familial risk for autism predicts a diagnosis of autism at 24 months of age. Predicting the future with brain imaging In a new study, Emerson et al. show that brain function in infancy can be used to accurately predict which high-risk infants will later receive an autism diagnosis. Using machine learning techniques that identify patterns in the brain’s functional connections, Emerson and colleagues were able to predict with greater than 96% accuracy whether a 6-month-old infant would develop autism at 24 months of age. These findings must be replicated, but they represent an important step toward the early identification of individuals with autism before its characteristic symptoms develop. Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social deficits and repetitive behaviors that typically emerge by 24 months of age. To develop effective early interventions that can potentially ameliorate the defining deficits of ASD and improve long-term outcomes, early detection is essential. Using prospective neuroimaging of 59 6-month-old infants with a high familial risk for ASD, we show that functional connectivity magnetic resonance imaging correctly identified which individual children would receive a research clinical best-estimate diagnosis of ASD at 24 months of age. Functional brain connections were defined in 6-month-old infants that correlated with 24-month scores on measures of social behavior, language, motor development, and repetitive behavior, which are all features common to the diagnosis of ASD. A fully cross-validated machine learning algorithm applied at age 6 months had a positive predictive value of 100% [95% confidence interval (CI), 62.9 to 100], correctly predicting 9 of 11 infants who received a diagnosis of ASD at 24 months (sensitivity, 81.8%; 95% CI, 47.8 to 96.8). All 48 6-month-old infants who were not diagnosed with ASD were correctly classified [specificity, 100% (95% CI, 90.8 to 100); negative predictive value, 96.0% (95% CI, 85.1 to 99.3)]. These findings have clinical implications for early risk assessment and the feasibility of developing early preventative interventions for ASD.

A Parent-Mediated Intervention That Targets Responsive Parental Behaviors Increases Attachment Behaviors in Children with ASD: Results from a Randomized Clinical Trial

The current study is a randomized clinical trial evaluating the efficacy of Focused Playtime Intervention (FPI) in a sample of 70 children with Autism Spectrum Disorder. This parent-mediated intervention has previously been shown to significantly increase responsive parental communication (Siller et al. in J Autism Dev Disord 43:540–555, 2013a). The current analyses focus on children’s attachment related outcomes. Results revealed that children who were randomly assigned to FPI showed bigger increases in attachment-related behaviors, compared to children assigned to the control condition. Significant treatment effects of FPI were found for both an observational measure of attachment-related behaviors elicited during a brief separation-reunion episode and a questionnaire measure evaluating parental perceptions of child attachment. The theoretical and clinical implications of these findings are discussed.

Walking, Gross Motor Development, and Brain Functional Connectivity in Infants and Toddlers

Abstract Infant gross motor development is vital to adaptive function and predictive of both cognitive outcomes and neurodevelopmental disorders. However, little is known about neural systems underlying the emergence of walking and general gross motor abilities. Using resting state fcMRI, we identified functional brain networks associated with walking and gross motor scores in a mixed cross-sectional and longitudinal cohort of infants at high and low risk for autism spectrum disorder, who represent a dimensionally distributed range of motor function. At age 12 months, functional connectivity of motor and default mode networks was correlated with walking, whereas dorsal attention and posterior cingulo-opercular networks were implicated at age 24 months. Analyses of general gross motor function also revealed involvement of motor and default mode networks at 12 and 24 months, with dorsal attention, cingulo-opercular, frontoparietal, and subcortical networks additionally implicated at 24 months. These findings suggest that changes in network-level brain–behavior relationships underlie the emergence and consolidation of walking and gross motor abilities in the toddler period. This initial description of network substrates of early gross motor development may inform hypotheses regarding neural systems contributing to typical and atypical motor outcomes, as well as neurodevelopmental disorders associated with motor dysfunction.

Promoting Early Identification of Autism in the Primary Care Setting: Bridging the Gap Between What We Know and What We Do

During the last decade, research on Autism Spectrum Disorder (ASD) has made tremendous progress with regard to early identification and diagnosis. These advances were made possible by a growing number of rigorous research studies with large sample sizes that utilized a combination of: (1) retrospective parent report and home video studies [1], (2) prospective studies of infant siblings of children with ASD [2], (3) population-wide studies of ASD screening tools [3], and (4) studies on the early stability of diagnostic classifications [4]. Advances in best practices related to early identification are reflected in a 2006 policy statement published by the American Academy of Pediatrics [5], and a corresponding set of clinical practice guidelines [6]. According to these guidelines, it is recommended that Primary Care Providers (PCPs; e.g., family physicians, pediatricians) administer formal screening tests during every well-child visit scheduled at 18 and 24 months, independent of known risk factors or reported concerns. Moreover, PCPs are urged to promptly refer children for Early Inter‐ vention1 services as soon as ASD is seriously considered.

Parent coaching increases the parents’ capacity for reflection and self-evaluation: results from a clinical trial in autism

ABSTRACT Family-centered parent coaching interventions in autism strive to encourage family engagement and support parent reflection and self-evaluation. This includes the parents’ capacity to: (1) carefully observe the child’s behavior; (2) reflect upon the child’s thoughts, motives, and feelings; (3) consider links between the child’s internal experiences and observable behavior; and (4) grapple with the complex interplay among the child’s experiences and behaviors, contextual factors, parenting strategies, as well as parental goals and emotions. The current study reports data from a clinical trial of Focused Playtime Intervention (FPI), a parent coaching intervention targeting responsive parental behaviors and child communication. Seventy children with autism between 2 and 6 years and their parents were randomly assigned to participate in FPI for 12 weeks or an active control intervention. The Insightfulness Assessment was administered and used (a) to classify parents’ baseline capacity for reflection and self-evaluation as either established (i.e., positively insightful) or emerging, and (b) to capture longitudinal change in the parents’ capacity between baseline, exit (~5 months after baseline), and follow up (~14 months after exit) using a dimensional composite subscale score. Results revealed a significant treatment effect of FPI on growth in the parents’ capacity for reflection and self-evaluation, conditional on the parents’ classification at baseline. That is, parents whose capacity for reflection and self-evaluation was classified as emerging at baseline (n = 42) showed higher rates of growth when assigned to FPI, compared to the control condition. A similar treatment effect was not found for parents whose baseline capacity for reflection and self-evaluation was classified as established (i.e., positively insightful). This is the first study to show that a family-centered parent coaching intervention effectively increases the capacity for reflection and self-evaluation in parents of young children with autism. This capacity may enable parents to adapt and implement intervention strategies flexibly across contexts, daily routines, and interactions.

Development of white matter circuitry in infants with fragile x syndrome

Importance Fragile X syndrome (FXS) is a genetic neurodevelopmental disorder and the most common inherited cause of intellectual disability in males. However, there are no published data on brain development in children with FXS during infancy. Objective To characterize the development of white matter at ages 6, 12, and 24 months in infants with FXS compared with that of typically developing controls. Design, Setting, and Participants Longitudinal behavioral and brain imaging data were collected at 1 or more time points from 27 infants with FXS and 73 typically developing controls between August 1, 2008, and June 14, 2016, at 2 academic medical centers. Infants in the control group had no first- or second-degree relatives with intellectual or psychiatric disorders, including FXS and autism spectrum disorder. Main Outcomes and Measures Nineteen major white matter pathways were defined in common atlas space based on anatomically informed methods. Diffusion parameters, including fractional anisotropy, were compared between groups using linear mixed effects modeling. Fiber pathways showing group differences were subsequently examined in association with direct measures of verbal and nonverbal development. Results There were significant differences in the development of 12 of 19 fiber tracts between the 27 infants with FXS (22 boys and 5 girls) and the 73 infants in the control group (46 boys and 27 girls), with lower fractional anisotropy in bilateral subcortical-frontal, occipital-temporal, temporal-frontal, and cerebellar-thalamic pathways, as well as 4 of 6 subdivisions of the corpus callosum. For all 12 of these pathways, there were significant main effects between groups but not for the interaction of age × group, indicating that lower fractional anisotropy was present and stable from age 6 months in infants with FXS. Lower fractional anisotropy values in the uncinate fasciculi were correlated with lower nonverbal developmental quotient in the FXS group (left uncinate, F = 10.06; false discovery rate–corrected P = .03; right uncinate, F = 21.8; P = .004). Conclusions and Relevance The results substantiate in human infants the essential role of fragile X gene expression in the early development of white matter. The findings also suggest that the neurodevelopmental effects of FXS are well established at 6 months of age.

A novel framework for the local extraction of extra-axial cerebrospinal fluid from MR brain images

The quantification of cerebrospinal fluid (CSF) in the human brain has shown to play an important role in early postnatal brain developmental. Extr a-axial fluid (EA-CSF), which is characterized by the CSF in the subarachnoid space, is promising in the early detection of children at risk for neurodevelopmental disorders. Currently, though, there is no tool to extract local EA-CSF measurements in a way that is suitable for localized analysis. In this paper, we propose a novel framework for the localized, cortical surface based analysis of EA-CSF. In our proposed processing, we combine probabilistic brain tissue segmentation, cortical surface reconstruction as well as streamline based local EA-CSF quantification. For streamline computation, we employ the vector field generated by solving a Laplacian partial differential equation (PDE) between the cortical surface and the outer CSF hull. To achieve sub-voxel accuracy while minimizing numerical errors, fourth-order Runge-Kutta (RK4) integration was used to generate the streamlines. Finally, the local EA-CSF is computed by integrating the CSF probability along the generated streamlines. The proposed local EA-CSF extraction tool was used to study the early postnatal brain development in typically developing infants. The results show that the proposed localized EA-CSF extraction pipeline can produce statistically significant regions that are not observed in previous global approach.

Language delay aggregates in toddler siblings of children with autism spectrum disorder

BackgroundLanguage delay is extremely common in children with autism spectrum disorder (ASD), yet it is unclear whether measurable variation in early language is associated with genetic liability for ASD. Assessment of language development in unaffected siblings of children with ASD can inform whether decreased early language ability aggregates with inherited risk for ASD and serves as an ASD endophenotype.MethodsWe implemented two approaches: (1) a meta-analysis of studies comparing language delay, a categorical indicator of language function, and language scores, a continuous metric, in unaffected toddlers at high and low familial risk for ASD, and (2) a parallel analysis of 350 unaffected 24-month-olds in the Infant Brain Imaging Study (IBIS), a prospective study of infants at high and low familial risk for ASD. An advantage of the former was its detection of group differences from pooled data across unique samples; an advantage of the latter was its sensitivity in quantifying early manifestations of language delay while accounting for covariates within a single large sample.ResultsMeta-analysis showed that high-risk siblings without ASD (HR-noASD) were three to four times more likely to exhibit language delay versus low-risk siblings without ASD (LR-noASD) and had lower mean receptive and expressive language scores. Analyses of IBIS data corroborated that language delay, specifically receptive language delay, was more frequent in the HR-noASD (n = 235) versus LR-noASD group (n = 115). IBIS language scores were continuously and unimodally distributed, with a pathological shift towards decreased language function in HR-noASD siblings. The elevated inherited risk for ASD was associated with lower receptive and expressive language scores when controlling for sociodemographic factors. For receptive but not expressive language, the effect of risk group remained significant even when controlling for nonverbal cognition.ConclusionsGreater frequency of language delay and a lower distribution of language scores in high-risk, unaffected toddler-aged siblings support decreased early language ability as an endophenotype for ASD, with a more pronounced effect for receptive versus expressive language. Further characterization of language development is warranted to refine genetic investigations of ASD and to elucidate factors influencing the progression of core autistic traits and related symptoms.