In the “Gray” Zone: Exploring the Diagnostic Course of Young Children with Unclear Presentation at Initial ASD Referral

Background: The benefits of early identification of autism spectrum disorder (ASD) and subsequent intervention have been well-documented in the existing literature. As a result, there has been an increasing interest in earlier evaluation and diagnosis of children with symptoms concerning for ASD. However, given the overlap of ASD with other developmental conditions (e.g., language disorder, developmental delay, behavioral difficulties), accurate identification can be difficult, especially in young children. 

Objectives: To examine the diagnostic course of young children referred for ASD evaluation who did not clearly meet diagnostic criteria at initial evaluation. 

Methods: Subjects include young children who were referred to a large, tertiary care medical center for an interdisciplinary evaluation of suspected ASD. All children included did not receive an ASD diagnosis at initial evaluation; however, all were deemed high-risk due to remaining prominent concerns for ASD and re-evaluation in 6-12 months was recommended. Only those children who returned for this recommended follow-up were included (n = 5). A descriptive review of diagnostic course and child characteristics was conducted.   

Results: The average age at which children completed initial evaluation was 38 months (SD = 17.79 months; range = 27-69 months). All children received either a language disorder (n =1) or global developmental delay diagnosis (n = 4) at initial evaluation. A diagnosis of Disruptive Behavior Disorder was also provided for 2 children. Some qualitative factors which may have contributed to the difficulty of diagnosis at first evaluation included: very young age, behavioral profiles including isolated strengths, lack of early intervention or other treatment, and limited information about early development. Follow-up evaluation occurred on average 10.75 months after initial evaluation (SD = 3.40, range = 6-14 months). The average age at which children completed follow-up evaluation was 47 months (SD = 18.52 months; range = 37-80 months). All 5 children were diagnosed with ASD at follow-up; a developmental delay diagnosis remained appropriate for the 4 children previously categorized as such. Continued data collection will allow for assessment of additional relevant contextual factors. Further investigation of social communication difficulties captured by the administrations of the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2) will be presented.

Conclusions: It appears initial sub-threshold concern for ASD manifested more clearly at re-evaluation in the children included in the present investigation, given that all children ultimately received an ASD diagnosis. Gaining insight into the factors related to delayed diagnosis in these young children with unclear initial symptoms may help inform clinical practice.