Objective

Delayed onset of independent walking is common in intellectual disability (ID). However, in children with autism spectrum disorders (ASD), delayed walking has not been reported as frequently, despite the high rate of concurrent ID in ASD. This study directly examined the relationship between delayed walking and severity of ID in children with ASD versus other non-ASD diagnoses.

Method

Participants were 1185 individuals (ASD, n = 903; non-ASD, n = 282) who received an assessment at age 4 to 12 years (6.89 ± 2.25) that yielded an estimate of nonverbal IQ (NVIQ) and retrospectively reported age of walking from the Autism Diagnostic Interview-Revised. The relationship between diagnostic group and delayed walking (defined as occurring at ≥16 months) as a function of NVIQ was explored using the Cox proportional hazards model.

Results

Children with ASD were less likely to exhibit delayed walking than those with non-ASD diagnoses, and this difference was larger at lower levels of NVIQ (P = .002). For example, rates of delayed walking for ASD and non-ASD were 13% and 19%, respectively, in those with NVIQ >85 but 31% and 60% in children with NVIQ <70.

Conclusions

Although lower IQ scores were associated with increased rates of late walking in both ASD and non-ASD groups, children with low IQ were more likely to show delayed walking in the absence of ASD. This raises the possibility of separate etiological pathways to ID in children with and without ASD.

The topic of this special issue on secondary versus idiopathic autism allows for discussion of how different groups may come to manifest autism spectrum disorder (ASD) or ASD-like symptoms despite important etiological differences. A related issue is that, because many of the social communication deficits that define ASD represent a failure to acquire developmentally expected skills, these same deficits would be expected to occur to some extent in all individuals with intellectual disability (ID). Thus, regardless of etiology, ASD symptoms may appear across groups of individuals with vastly different profiles of underlying deficits and strengths. In this focused review, we consider the impact of ID on the diagnosis of ASD. We discuss behavioral distinctions between ID and ASD, in light of the diagnostic criterion mandating that ASD should not be diagnosed if symptoms are accounted for by ID or general developmental delay. We review the evolution of the autism diagnosis and ASD diagnostic tools to understand how this distinction has been conceptualized previously. We then consider ways that operationalized criteria may be beneficial for making the clinical distinction between ID with and without ASD. Finally, we consider the impact of the blurred diagnostic boundaries between ID and ASD on the study of secondary versus idiopathic ASD. Especially pertinent to this discussion are findings that a diagnosis of ID in the context of an ASD diagnosis may be one of the strongest indicators that an associated condition or specific etiological factor is present (i.e., secondary autism).

The ability to demonstrate and quantify changes in social communication skills has been hindered by a lack of existing measures with appropriate standardization and psychometric properties. Such a measure would be helpful for research in many populations but would be particularly crucial for detecting incremental changes in youth with neurodevelopmental disorders who might gain skills but still lag substantially behind same-age peers. Although study designs and statistical methods are under development to try to account for slow and/or nonlinear, but potentially meaningful, improvements,¹ there is a dearth of measures designed to capture growth and loss of social communication skills. This opinion piece outlines the argument for such a measure and the primary issues to consider in its development.

Testing cognitive skill development is important for diagnostic, prognostic, and monitoring purposes, especially for young children and individuals with neurodevelopmental disorders. Developmental tests have been created for infants and toddlers, while traditional IQ tests are often employed beginning in the later preschool period. However, IQ tests rely on developmental skills that are rapidly changing during early childhood. Here, we introduce the idea of prerequisite skills in developmental domains, which are discrete skills required for, but not explicitly tested by, traditional IQ tests. Focusing on general cognition, particularly among children with a chronological or mental age under 4 years, may fail to capture important nuances in skill development. New skill-based assessments are needed in general, and in particular for categorization, which is foundational to higher-order cognitive skills. Novel measures quantifying categorization skills would provide a more sensitive measure of development for young children and older individuals with low developmental levels.

Structural magnetic resonance imaging (MRI) scans at high spatial resolution can detect potential foci of early brain dysmaturation in children with autism spectrum disorders (ASD). In addition, comparison between MRI and behavior measures over time can identify patterns of brain change accompanying specific outcomes. We report structural MRI data from two time points for a total of 84 scans in children with ASD and 30 scans in typical controls (mean age time one = 4.1 years, mean age at time two = 6.6 years). Surface-based cortical morphometry and linear mixed effects models were used to link changes in cortical anatomy to both diagnostic status and individual differences in changes in language and autism severity. Compared with controls, children with ASD showed accelerated gray matter volume gain with age, which was driven by a lack of typical age-related cortical thickness (CT) decrease within 10 cortical regions involved in language, social cognition, and behavioral control. Greater expressive communication gains with age in children with ASD were associated with greater CT gains in a set of right hemisphere homologues to dominant language cortices, potentially identifying a compensatory system for closer translational study. Hum Brain Mapp 37:2616-2629, 2016. © 2016 Wiley Periodicals, Inc.

In "The Need for a Clinically Useful Schema of Social Communication," Blank et al. present an observation and coding method (The Initiating, Responding, Expectancy Violations [IREV] schema) for identifying "expectancy violations (EVs)," which may signal clinically significant departures from normal social communication behavior (eg, in individuals with autism spectrum disorder [ASD]).¹ The authors point out that "historically, observation of a patient's (social communication) has not been part of the routine psychiatric mental status examination," and argue that this is an important missed opportunity for clinicians. Several direct observation methods exist for identifying and/or monitoring changes in social communication deficits associated with ASD.² Despite their established diagnostic validity, it remains true that these measures used in isolation will result in a relatively high rate of "false positives"-usually comprising children who are better described with other diagnoses (eg, intellectual disability, language disorder, attention-deficit/hyperactivity disorder [ADHD]).² This underscores the critical importance of context when interpreting observed social communication deficits.

Background

Recent large-scale initiatives have led to systematically collected phenotypic data for several rare genetic conditions implicated in autism spectrum disorder (ASD). The onset of developmentally expected skills (e.g. walking, talking) serve as readily quantifiable aspects of the behavioral phenotype. This study's aims were: (a) describe the distribution of ages of attainment of gross motor and expressive language milestones in several rare genetic conditions, and (b) characterize the likelihood of delays in these conditions compared with idiopathic ASD.

Methods

Participants aged 3 years and older were drawn from two Simons Foundation Autism Research Initiative registries that employed consistent phenotyping protocols. Inclusion criteria were a confirmed genetic diagnosis of one of 16 genetic conditions (Simons Searchlight) or absence of known pathogenic genetic findings in individuals with ASD (SPARK). Parent-reported age of acquisition of three gross motor and two expressive language milestones was described and categorized as on-time or delayed, relative to normative expectations.

Results

Developmental milestone profiles of probands with genetic conditions were marked by extensive delays (including nonattainment), with highest severity in single gene conditions and more delays than idiopathic ASD in motor skills. Compared with idiopathic ASD, the median odds of delay among the genetic groups were higher by 8.3 times (IQR 5.8-16.3) for sitting, 12.4 times (IQR 5.3-19.5) for crawling, 26.8 times (IQR 7.7-41.1) for walking, 2.7 times (IQR 1.7-5.5) for single words, and 5.7 times (IQR 2.7-18.3) for combined words.

Conclusions

Delays in developmental milestones, particularly in gross motor skills, are frequent and may be among the earliest indicators of differentially affected developmental processes in specific genetically defined conditions associated with ASD, as compared with those with clinical diagnoses of idiopathic ASD. The possibility of different developmental pathways leading to ASD-associated phenotypes should be considered when deciding how to employ specific genetic conditions as models for ASD.

There is a critical need for accurate screening tools for autism spectrum disorder in very young children so families can access tailored intervention services as early as possible. However, there are few screeners designed for children 18-24 months. Developing screeners that pick up on the signs of autism spectrum disorder in very young children has proved even more challenging. In this study, we examined a new autism-specific parent-report screening tool, the Early Screening for Autism and Communication Disorders for children between 12 and 36 months of age. Field-testing was done in five sites with 471 children screened for communication delays in primary care or referred for familial risk or concern for autism spectrum disorder. The Early Screening for Autism and Communication Disorders was tested in three age groups: 12-17, 18-23, and 24-36 months. A best-estimate diagnosis of autism spectrum disorder, developmental delay, or typical development was made. Analyses examined all 46 items and identified 30 items that best discriminated autism spectrum disorder from the non-spectrum groups. Cutoffs were established for each age group with good sensitivity and specificity. Results provide preliminary support for the accuracy of the Early Screening for Autism and Communication Disorders as an autism-specific screener in children 12-36 months with elevated risk of communication delay or autism spectrum disorder.

Objective

To identify and summarize clinical practice guidelines for autism spectrum disorder (ASD) and intellectual disability (ID) for the Package of Interventions for Rehabilitation for the World Health Organization (WHO).

Data sources

Academic databases, Google Scholar, guideline databases, and professional society websites were searched using the general criteria "ASD/ID" AND "rehabilitation" AND "guideline," restricted to English-only guidelines.

Study selection

Work group members independently screened titles and abstracts (1952 ASD; 1027 ID) and excluded articles if not (1) a guideline; (2) about rehabilitation; (3) published since 2008; or (4) about ASD/ID. Full-text screening (29 ASD; 5 ID) involved 3 additional exclusion criteria: (1) contained conflict of interest; (2) lacked information on strength of recommendation; or (3) failed the Appraisal of Guidelines for Research and Evaluation II instrument. Six guidelines (4 ASD: 2 on youth, 1 on adults, 1 on all ages; 2 ID: 1 on challenging behaviors, 1 on mental health) resulted.

Data extraction

Work group members extracted 524 recommendations (386 ASD; 138 ID) from the guidelines including the level of evidence, diagnostic and age group, recommendation type (assessment, intervention, service), target, and valence.

Data synthesis

Of the 270 intervention recommendations (212 ASD; 58 ID), only 36 for ASD and 47 for ID were empirically based. Most comprised biomedical (23%), pharmacologic (29%), and psychosocial (21%) interventions for ASD and behavioral (14%), pharmacologic (29%), and psychological (14%) interventions for ID. Intervention recommendations primarily targeted coexisting conditions (56% ASD; 93% ID), whereas core symptoms received much less attention (26% ASD).

Conclusions

Clinical practice guidelines reviewed for ASD and ID primarily contained recommendations based on expert opinion, with the plurality of recommendations relating to pharmacologic treatment. Vital next steps include identifying relevant interventions for inclusion in the WHO Package and continuing to conduct rigorous intervention research, particularly on core symptoms of these conditions, to extend recommendations for high-quality guidelines.

Autism is a brain disorder characterized by social impairments. Progress in understanding autism has been hindered by difficulty in obtaining brain-relevant tissues (eg, cerebrospinal fluid [CSF]) by which to identify markers of disease and targets for treatment. Here, we overcome this barrier by providing evidence that mean CSF concentration of the "social" neuropeptide arginine vasopressin (AVP) is lower in children with autism versus controls. CSF AVP concentration also significantly differentiates individual cases from controls and is associated with greater social symptom severity in children with autism. These findings indicate that AVP may be a promising CSF marker of autism's social deficits. Ann Neurol 2018;84:611-615.