Onset Patterns Prior to 36 Months in Autism Spectrum Disorders

Background: Observational data from the past several decades suggest variation in the onset of autism symptomatology. At present, the relationship between symptom onset pattern and outcome in children with an Autism Spectrum Disorder (ASD) remains unclear.

Objectives: The overarching goal of the present study was to investigate differences in current functioning among children with three different autism onset patterns: plateau, regressed, and those without regression or plateau. More specifically, we examined present group differences in parental report of milestone achievement, autism symptom severity, autism diagnosis, presence or absence of cognitive impairment and phrase speech, and behavioral-educational outcomes.

Methods: Cross-sectional data were collected from parents of children aged 3–17 years with an ASD who were recruited through a U.S-based online research database. Parental report of developmental characteristics was assessed through a parent questionnaire and autism symptoms were measured via the Social Responsiveness Scale (Constantino et al., 2003) and Social Communication Questionnaire (SCQ; Western Psychological Services, Los Angeles). Exclusion criteria for this study included parent report of developmental concerns or loss of skills after their child reached 3 years of age, children that did not meet a cutoff score of ≥15 on the SCQ (to screen for an ASD), or those with a previous diagnosis of tuberous sclerosis and/or Fragile X. The final study sample totaled 2,720 participants. Multiple Linear and logistic regression models were then built to examine outcomes while controlling for demographic variables.

Results: Children of parents who reported a loss of skills were found to have later parental concerns, earlier first words and steps, delayed phrase speech and toilet training compared to children without regression or plateau (p<.001). Children with a developmental plateau had later parental concerns (p<.001). Both children with regression (39%) and plateau (17%) demonstrated elevated autism symptom scores, earlier age at diagnosis, and an increased risk for currently being non-verbal (OR 1.92; OR 1.55), diagnosed with autistic disorder (OR 2.23; OR 1.35), in a supportive academic setting (OR 1.85; OR 1.41) and having a 1:1 classroom aide within that setting (OR 1.63; OR 1.44) compared to children without regression or plateau (all p<.05).

Conclusions: Results from the multivariate analyses indicated that children with regression have a distinct developmental pattern marked by less delayed early development; however, following regression, these children evidenced elevated autism symptom scores and an increased risk for poorer outcomes when compared with their affected peers. These findings were particularly robust for the children of parents who reported the regression as severe. For children with a plateau or developmental halt, a very under researched group, several alarming outcomes emerged from the data. These findings hold important implications to theory, policy, and practice.