Recently emerging intervention studies for toddlers with autism spectrum disorders (ASD) were reviewed through a systematic assessment of intervention outcomes, research rigor, and intervention features. The review includes published peer-reviewed experimental studies of toddlers with high risk for or diagnosis of ASD in which the majority of interventions occurred before age 36 months. Of 20 identified research studies, 6 were group comparison studies, all of which showed small to large magnitudes of effect when a uniform metric was applied. Fourteen were single-case design (SCD) studies, all of which reported effects on a variety of outcomes. When grouped by area of intervention focus (communication, general development, family well-being, imitation, joint attention, and play), commonly identified needs within focus areas were for replication, common measures, and authentic practices. A majority of studies in most focus areas showed strong to acceptable levels of research rigor, though this is an area of ongoing need.
Keywords: autism spectrum disorders, disabilities and development delays, Part C services, components of practice, infants and toddlers, young children, instruction
Research on intervention for toddlers with autism spectrum disorders (ASD) began appearing in the literature over the past decade in response to considerable interest in the potential for earlier intervention to enhance outcomes. These early investigations were furthered by improved general awareness of ASD and early identification initiatives that included toddler screening protocols (e.g., Robins, Fein, Barton, & Green, 2001), recommendation by the American Academy of Pediatrics for universal 18-month ASD screening at toddler well-child checks (Johnson & Myers, 2007), and a toddler version of the Autism Diagnostic Observation Schedule (Luyster et al., 2008). Recently, toddler research in ASD received a boost as private and public funding prioritized early intervention research (Autism Speaks, 2011; Interagency Autism Coordinating Committee, 2005). The emergent stage of toddler intervention research in ASD presents an opportunity to inform early intervention practice and future research at an important juncture.
Our assessment of the need for review of toddler intervention studies first considered reviews of interventions for young children with ASD already conducted, all of which were found to have included all or a majority of children older than age 36 months. These reviews addressed parent-implemented early intervention (Brookman-Frazee, Vismara, Drahota, Stahmer, & Openden, 2009; McConachie & Diggle, 2007), comprehensive intervention programs (Eikeseth, 2009; Eldevik et al., 2009; Howlin, Magiati, & Charman, 2009; Reichow & Wolery, 2009; Rogers & Vismara, 2008; Virués-Ortega, 2010), and interventions to facilitate social interaction (Reichow & Volkmar, 2010). Six of the 10 reviews focused on early intensive behavioral intervention studies, the most studied comprehensive intervention approach for preschoolers with autism, and all reported evidence of effects but noted limitations related to methodological concerns (Eikeseth, 2009; Eldevik et al., 2009; Howlin et al., 2009; Reichow, 2012; Reichow & Wolery, 2009; Virués-Ortega, 2010).
Intervention for preschoolers (ages 3 through 5) typically targets more developmentally advanced outcomes than those for toddlers (ages 1 to 3), is more oriented to group settings, and is guided by policy less integrally centered on families. For these reasons, and because toddlers and families were not prominently featured in the earlier reviews of preschool interventions, findings on preschool interventions can be difficult to generalize to toddlers and their families.
Although the need is clear for toddler intervention research to be reviewed separately, the relatively small collection of studies and their diversity of research designs, intervention purposes, and outcome measures are limiting factors. …