AbstractAutism spectrum disorder (ASD) has a variety of causes, and its clinical expression is generally associated with substantial disability throughout the lifespan. Recent advances have led to ...earlier diagnosis, and deep phenotyping efforts focused on high risk infants have helped advance the characterization of early behavioral trajectories. Moreover, biomarkers that measure early structural and functional connectivity, visual orienting, and other biological processes have shown promise in detecting the risk of autism spectrum disorder even before the emergence of overt behavioral symptoms. Despite these advances, the mean age of diagnosis is still 4-5 years. Because of the broad consistency in published guidelines, parameters for high quality comprehensive assessments are available; however, such models are resource intensive and high demand can result in greatly increased waiting times. This review describes advances in detecting early behavioral and biological markers, current options and controversies in screening for the disorder, and best practice in its diagnostic evaluation including emerging data on innovative service models.
•There is robust evidence that behavioral signs of ASD can be detected by 1 year.•Risk markers extend from atypical social communication to motor delays.•Unusual trajectories of language and ...cognitive skills are reported in ASD.•A combined behavioral and biomarker approach may help with early detection of ASD.
Earlier identification and diagnosis of autism spectrum disorders (ASDs) can improve opportunities for children to benefit from intervention and lessen the burden on concerned parents. This review summarizes current knowledge about early signs of autism. Convergent data from both retrospective studies and prospective studies of high-risk infants indicate that ASD symptoms emerge in the first two years of life, affecting multiple developmental domains, mapping onto symptom dimensions consistent with current diagnostic frameworks including social-communication, and repetitive interests/behaviors but also extending to motor delays and atypical regulation of attention and emotion. Recent findings have shed new light on patterns of symptom onset and progression, and promise to inform early detection and diagnosis. Further attention to effective application of new findings and related challenges in building health system capacity to ensure timely access to specialized assessment and interventions is needed to fully realize the promise of improved outcomes resulting from this research.
Autism spectrum disorder is associated with diverse social, educational, and occupational challenges. To date, no standardized, internationally accepted tools exist to assess autism spectrum ...disorder–related functioning. World Health Organization’s International Classification of Functioning, Disability and Health can serve as foundation for developing such tools. This study aimed to identify a comprehensive, a common brief, and three age-appropriate brief autism spectrum disorder Core Sets. Four international preparatory studies yielded in total 164 second-level International Classification of Functioning, Disability and Health candidate categories. Based on this evidence, 20 international autism spectrum disorder experts applied an established iterative decision-making consensus process to select from the candidate categories the most relevant ones to constitute the autism spectrum disorder Core Sets. The consensus process generated 111 second-level International Classification of Functioning, Disability and Health categories in the Comprehensive Core Set for autism spectrum disorder—one body structure, 20 body functions, 59 activities and participation categories, and 31 environmental factors. The Common Brief Core Set comprised 60 categories, while the age-appropriate core sets included 73 categories in the preschool version (0- to 5-year-old children), 81 in the school-age version (6- to 16-year-old children and adolescents), and 79 in the older adolescent and adult version (⩾17-year-old individuals). The autism spectrum disorder Core Sets mark a milestone toward the standardized assessment of autism spectrum disorder–related functioning in educational, administrative, clinical, and research settings.
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.
Training primary care providers to provide diagnostic assessments for autism spectrum disorder (ASD) decreases wait times and improves diagnostic access. Outcomes related to the quality of these ...assessments and the impacts on system capacity have not been systematically examined. This systematic review identifies and summarizes published studies that included ASD diagnostic training for primary care providers (PCPs) and aims to guide future training and evaluation methods.
Systematic searches of electronic databases, reference lists, and journals identified 6 studies that met 3 inclusion criteria: training for PCPs, community setting, and training outcome(s) reported. These studies were critically reviewed to characterize (1) study design, (2) training model, and (3) outcomes.
All studies were either pre-post design or nonrandomized trials with a relatively small number of participants. There was considerable heterogeneity among studies regarding the training provided and the program evaluation process. The most evaluated outcomes were access to autism diagnosis and accuracy of diagnosis.
Training PCPs to make ASD diagnoses can yield high diagnostic agreement with specialty teams' assessments and reduce diagnostic wait times. Current data are limited by small sample size, poor to fair quality study methodology, and heterogenous study designs and outcome evaluations. Evidence is insufficient to draw conclusions about the overall effects of training PCPs for ASD diagnostic assessments. Since further research is still needed, this review highlights which outcomes are relevant to consider when evaluating the quality of ASD assessments across the continuum of approaches.
The diagnosis of autism spectrum disorder (ASD) has been found to be remarkably stable but few studies have followed children not initially diagnosed with ASD beyond 3 years of age to examine late or ...delayed diagnoses. The present study used a prospective familial-risk design to identify children who had undergone multiple comprehensive assessments in preschool and were determined to be negative for ASD only to meet criteria for ASD when tested in middle childhood.
Data were pooled across 3 research teams studying later-born siblings of children with ASD. Fourteen children met inclusion criteria for the late-diagnosed group and were compared with a large sample of high- and low-risk siblings from the same sites who had ASD or typical development (TD) outcomes at 3 years of age.
As a group, the late-diagnosed children scored between the TD and ASD groups on most measures administered at 3 years and differed significantly from the ASD group on most measures. However, there was significant heterogeneity among the late-diagnosed cases. Seven showed very little evidence of ASD in preschool, whereas 7 demonstrated subtle, subthreshold symptomatology.
Some children with ASD might present with a subtle phenotype early in life or show a prolonged time course of symptom development. This emphasizes the need for screening and surveillance schedules that extend past 36 months and continued evaluation of any child who presents with atypical early development and/or high-risk status. The findings also shed light on reasons why the mean age of ASD diagnosis remains older than 4 years.
Families with early concerns about infant symptoms of ASD have limited access to experienced professionals for screening and guidance. Telehealth has been used to reduce access disparities in other ...pediatric populations and has shown promise in parent-implemented interventions for ASD. We investigated the feasibility of a novel level-2 telehealth assessment of infants’ early social communication and ASD symptoms, the Telehealth Evaluation of Development for Infants (TEDI). Parents of eleven infants aged 6–12 months were coached to administer specific semi-structured behavioral probes. Initial feasibility, reliability, and acceptability benchmarks were met. These findings suggest the feasibility of screening infants via telehealth, and are supportive of further large-scale efforts to validate this method for longitudinal monitoring of symptomatic infants in community settings.
Objective: First-degree relatives of persons with an autism spectrum disorder (ASD) are at increased risk for ASD-related characteristics. As little is known about the early expression of these ...characteristics, this study characterizes the non-ASD outcomes of 3-year-old high-risk (HR) siblings of children with ASD. Method: Two groups of children without ASD participated: 507 HR siblings and 324 low-risk (LR) control subjects (no known relatives with ASD). Children were enrolled at a mean age of 8 months, and outcomes were assessed at 3 years. Outcome measures were Autism Diagnostic Observation Schedule (ADOS) calibrated severity scores, and Mullen Verbal and Non-Verbal Developmental Quotients (DQ). Results: At 3 years, HR siblings without an ASD outcome exhibited higher mean ADOS severity scores and lower verbal and non-verbal DQs than LR controls. HR siblings were over-represented (21% HR versus 7% LR) in latent classes characterized by elevated ADOS severity and/or low to low-average DQs. The remaining HR siblings without ASD outcomes (79%) belonged to classes in which they were not differentially represented with respect to LR siblings. Conclusions: Having removed a previously identified 18.7% of HR siblings with ASD outcomes from all analyses, HR siblings nevertheless exhibited higher mean levels of ASD severity and lower levels of developmental functioning than LR children. However, the latent class membership of four-fifths of the HR siblings was not significantly different from that of LR control subjects. One-fifth of HR siblings belonged to classes characterized by higher ASD severity and/or lower levels of developmental functioning. This empirically derived characterization of an early-emerging pattern of difficulties in a minority of 3-year-old HR siblings suggests the importance of developmental surveillance and early intervention for these children. (Contains 1 figure and 7 tables.)
Background
The diagnosis of autism spectrum disorder (ASD) made before age 3 has been found to be remarkably stable in clinic‐ and community‐ascertained samples. The stability of an ASD diagnosis in ...prospectively ascertained samples of infants at risk for ASD due to familial factors has not yet been studied, however. The American Academy of Pediatrics recommends intensive surveillance and screening for this high‐risk group, which may afford earlier identification. Therefore, it is critical to understand the stability of an ASD diagnosis made before age 3 in young children at familial risk.
Methods
Data were pooled across seven sites of the Baby Siblings Research Consortium. Evaluations of 418 later‐born siblings of children with ASD were conducted at 18, 24, and 36 months of age and a clinical diagnosis of ASD or Not ASD was made at each age.
Results
The stability of an ASD diagnosis at 18 months was 93% and at 24 months was 82%. There were relatively few children diagnosed with ASD at 18 or 24 months whose diagnosis was not confirmed at 36 months. There were, however, many children with ASD outcomes at 36 months who had not yet been diagnosed at 18 months (63%) or 24 months (41%).
Conclusions
The stability of an ASD diagnosis in this familial‐risk sample was high at both 18 and 24 months of age and comparable with previous data from clinic‐ and community‐ascertained samples. However, almost half of the children with ASD outcomes were not identified as being on the spectrum at 24 months and did not receive an ASD diagnosis until 36 months. Thus, longitudinal follow‐up is critical for children with early signs of social‐communication difficulties, even if they do not meet diagnostic criteria at initial assessment. A public health implication of these data is that screening for ASD may need to be repeated multiple times in the first years of life. These data also suggest that there is a period of early development in which ASD features unfold and emerge but have not yet reached levels supportive of a diagnosis.
Opportunities to communicate first-person perspectives are essential for self-determination. However, many autistic youth are excluded from sharing their perspectives, specifically those who are ...minimally verbal or with lower intellectual functioning. Current challenges to capturing their voices include a lack of appropriate inclusive methodologies. Propose an inclusive strength-oriented method to capture first-person perspectives of autistic adolescents. Our protocol (“Autism Voices”) includes a pre-interview survey and semi-structured interview using universal design strategies. It was piloted with 33 participants who were representative of diverse language and cognitive abilities. A coding scheme was developed to identify communicative acts used by participants and mitigation strategies used by interviewers to enhance communication. Interviewer strategies that enhanced communication included question formulation, use of pictures, offering various output modalities, and flexible implementation of the protocol. Non-verbal and alternative communication responses (e.g. choosing to not respond) were informative to youth’s lived experience, especially for minimally verbal participants. Overall, our results highlight that communication goes beyond verbally answering questions and that participants’ unconventional communication conveyed rich information. Autism Voices provides a promising method to promote the inclusion of autistic youth in research.
Lay abstract
The perspective of autistic individuals is often left uncaptured, and as a result they are often excluded from making decisions that impact them. Conventional communication can be challenging for many autistic individuals, especially those who are minimally verbal or who have an associated intellectual disability. Currently, a lack of appropriate methods to capture voices across the spectrum is a barrier. In the present study, we developed the Autism Voices protocol using universal design principles to capture the perspectives and experiences of autistic youth with a range of language or intellectual abilities. This protocol was then used with 33 autistic youth aged 11 to 18 years. A scoring rubric was developed to capture the unconventional communication used by the participants and the mitigation strategies used by interviewers to facilitate the interview. Many components of the protocol were found to effectively facilitate communication between the participant and interviewer, including the use of picture cards to support verbal questions/prompts, the fact that participants could respond with their preferred communication methods (writing, texting, pointing), and the fact that interviews were applied flexibly to adapt to each participant. Unconventional communication and mitigation strategies were mostly observed in interviews with minimally verbal individuals, but a fine-grained analysis showed participants were still communicating something through this unconventional communication. Our protocol could help promote the inclusion of more autistic individuals in research and showed that unconventional modes of communication like echolalia provide an understanding that participants’ are invested in conversations and certain topics are more meaningful than others.
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