Parent-Reported Features Associated with Clinical Ratings of Autism Severity in Preschool Children:

Background: Early detection of autism spectrum disorder (ASD) symptoms facilitates early intervention associated with improved developmental outcomes. Developmental improvements gained in early intervention programs are most often seen in relation to co-occurring conditions, such as adaptive and cognitive delays, instead of the ASD diagnostic symptoms of social communication and interaction, and restricted interests and repetitive behaviors. More research is needed to identify parent-reported features of ASD associated with diagnostic symptom severity so those features can be evaluated in intervention programs.

Objectives: In order to highlight potentially modifiable child characteristics, this study aimed to identify parent-reported features associated with clinical ratings of ASD severity in preschool children. 

Methods: Three groups of children 2-5 years old were ascertained for the Study to Explore Early Development (SEED): (1) those with known ASD, (2) those with another developmental delay or disorder, and (3) those identified through birth certificate records. All children were screened for ASD with the Social Communication Questionnaire upon enrollment. Children who screened positive for ASD or had a previous ASD diagnosis were asked to complete an in-person assessment that consisted of the Autism Diagnostic Observation Schedule (ADOS) and Mullen Scales of Early Learning (MSEL). Caregivers completed the Autism Diagnostic Interview – Revised (ADI-R) and an interview that gathered sociodemographic information. Children classified as ASD met ADOS criteria and either standard ADI-R criteria or one of three alternate ADI-R criteria (alternate ADI-R criteria are described elsewhere; Wiggins et al., 2015).

The association between domain scores from the ADI-R and ASD severity from the ADOS was assessed using regression analysis. Independent and dependent variables were assessed for multicollinearity. The following covariates were entered into the model: child age, child ethnicity, child race, child sex, household income, maternal age, maternal education, and MSEL expressive language, receptive language, fine motor, and visual reception scores. ADI-R domain scores associated with ASD severity were further evaluated to detect individual diagnostic items within those domains associated with ASD severity.

Results: 707 children met the SEED ASD case definition. Higher household income was associated with higher ASD severity, and more advanced expressive language skills was associated with lower ASD severity. Higher ADI-R behavioral and social domain scores were associated with higher ASD severity, when controlling for household income and expressive language ability. Within the ADI-R behavioral domain, more hand and finger mannerisms, repetitive use of objects, and unusual sensory response were each associated with higher ASD severity scores; more compulsions/rituals were associated with lower ASD severity scores. Within the ADI-R social domain, deficits in eye gaze, response to the approach of other children, and sharing enjoyment were each associated with higher ASD severity scores; less interest in other children was associated with lower ASD severity scores.

Conclusions: Our results highlight specific parent-reported ASD symptoms that are associated with clinical perception of diagnostic presentation and can be evaluated in intervention programs and research protocols. These results also highlight the need for multi-domain treatments that address the many needs of children with ASD and their families. Implications for intervention will be discussed.