In this comprehensive systematic review and meta-analysis of group design studies of nonpharmacological early interventions designed for young children with autism spectrum disorder (ASD), we report summary effects across 7 early intervention types (behavioral, developmental, naturalistic developmental behavioral intervention [NDBI], TEACCH, sensory-based, animal-assisted, and technology-based), and 15 outcome categories indexing core and related ASD symptoms. A total of 1,615 effect sizes were gathered from 130 independent participant samples. A total of 6,240 participants, who ranged in age from 0 -8 years, are represented across the studies. We synthesized effects within intervention and outcome type using a robust variance estimation approach to account for the nesting of effect sizes within studies. We also tracked study quality indicators, and report an additional set of summary effect sizes that restrict included studies to those meeting prespecified quality indicators. Finally, we conducted moderator analyses to evaluate whether summary effects across intervention types were larger for proximal as compared with distal effects, and for context-bound as compared to generalized effects. We found that when study quality indicators were not taken into account, significant positive effects were found for behavioral, developmental, and NDBI intervention types. When effect size estimation was limited to studies with randomized controlled trial (RCT) designs, evidence of positive summary effects existed only for developmental and NDBI intervention types. This was also the case when outcomes measured by parent report were excluded. Finally, when effect estimation was limited to RCT designs and to outcomes for which there was no risk of detection bias, no intervention types showed significant effects on any outcome.

An ever-growing literature has aimed to determine how individuals with autism spectrum disorder (ASD) differ from their typically developing (TD) peers on measures of multisensory integration (MSI) and to ascertain the degree to which differences in MSI are associated with the broad range of symptoms associated with ASD. Findings, however, have been highly variable across the studies carried out to date. The present work systematically reviews and quantitatively synthesizes the large literature on audiovisual MSI in individuals with ASD to evaluate the cumulative evidence for (a) group differences between individuals with ASD and TD peers, (b) correlations between MSI and autism symptoms in individuals with ASD and (c) study level factors that may moderate findings (i.e., explain differential effects) observed across studies. To identify eligible studies, a comprehensive search strategy was employed using the ProQuest search engine, PubMed database, forwards and backwards citation searches, direct author contact, and hand-searching of select conference proceedings. A significant between-group difference in MSI was evident in the literature, with individuals with ASD demonstrating worse audiovisual integration on average across studies compared to TD controls. This effect was moderated by mean participant age, such that between-group differences were more pronounced in younger samples. The mean correlation between MSI and autism and related symptomatology was also significant, indicating that increased audiovisual integration in individuals with ASD is associated with better language/communication abilities and/or reduced autism symptom severity in the extant literature. This effect was moderated by whether the stimuli were linguistic versus non-linguistic in nature, such that correlation magnitudes tended to be significantly greater when linguistic stimuli were utilized in the measure of MSI. Limitations and future directions for primary and meta-analytic research are discussed.

We examined the quality of evidence supporting the effects of Naturalistic Developmental Behavioral Interventions (NBDIs) for facilitating change in young children with autism. We also investigated whether effects varied as a function of specific features of the intervention, samples, and outcomes measured. Twenty‐seven studies testing the effects of NDBIs were extracted from data collected for the Autism Intervention Meta‐analysis (Project AIM), a comprehensive meta‐analysis of group design, nonpharmacological intervention studies for children with autism aged 0–8 years. We extracted effect sizes for 454 outcomes from these studies for use in meta‐regression analyses testing associations between intervention effects and mean participant chronological age, language age, autism symptomatology, percentage of sample reported as male, cumulative intervention intensity, interventionist, outcome boundedness, outcome proximity, and risk of parent/teacher training correlated measurement error. The extant literature on NDBIs documents effects on social communication, language, play, and cognitive outcomes. However, our confidence in the positive and significant summary effects for these domains is somewhat limited by methodological concerns. Intervention effects were larger for context‐bound outcomes (relative to generalized), and for proximal outcomes (relative to distal). Our results indicate that NDBIs have promise as an approach for supporting development for some, but not all of the core and related features of autism in early childhood. Confidence in summary effect estimates is limited by study quality concerns, particularly an overreliance on measures subject to high detection bias. The results of this review support the use of proximity and boundedness as indicators of the limits of intervention effects. Lay summary Naturalistic Developmental Behavioral Interventions may increase language, social communication, play skills, and cognition in young children with autism, but these increases are largest for skills directly targeted by the intervention, and in contexts that are similar to that of the intervention. These conclusions are tempered by some concerns regarding research design across the studies that have been conducted to date. Autism Res 2021, 14: 817–834. © 2021 International Society for Autism Research and Wiley Periodicals LLC

No abstract