UC San Diego
Investigation of Early Symptom Presentation in Children Under Age Three with Risk for Autism
- Author(s): Bacon, Elizabeth Catherine
- et al.
Given the rise in frequency of autism spectrum disorder (ASD) diagnoses and the importance of early diagnosis for access to intervention services, there has been a push for early identification. Several early markers of ASD have been identified, however, these markers have largely been established in baby siblings of children with ASD, and the extent of generalization to a non-sibling population is unknown. Additionally, diagnostic stability at young ages is somewhat variable, pointing to a need for further research to improve early identification processes. The current project studied 299 toddlers, including early- identified cases of ASD (identified at-risk for ASD at initial and subsequent evaluations), late-identified cases of ASD (initially considered nonspectrum, then identified at-risk for ASD at a subsequent evaluation), children with language delay, and typically developing children. Every six to twelve months children participated in a battery of assessments including developmental and diagnostic tests, eye-tracking, an exploration task, and a free play observation. Aims were to : 1) assess whether early markers of ASD identified in the baby sibling literature were replicable within the current sample, 2) identify early behavioral markers within late-identified ASD cases, and 3) analyze trajectories of development until age three. A reduction in social-communication skills was seen in both ASD groups at initial assessments, including increased preference for non-social stimuli, increased stereotypic play, and reduced exploration, use of gestures, social vocalizations, and social referencing. However, the late-identified cases of ASD were difficult to differentiate from children with language delay. ASD groups showed different developmental trajectories; the early-identified cases showed more impairment initially, but showed greater improvement over time than the late- identified ASD group. Many of the early behavioral markers identified in the baby sibling literature were replicated. Increased preference for geometric stimuli, increased stereotypic play, and reduced exploration and social referencing indicated the highest risk for ASD and may be useful for identifying ASD in toddlers. Additionally, different developmental trajectories between early and late-identified children with ASD point to possible subgroups of ASD. These data provide important information regarding early development of ASD and provide direction for future refinement of the early detection process