Can Temperament Add to Our Understanding of Early Autism? Differences Between Toddlers Who Screen Positive for Autism v. Developmental Delay

Background: Previous studies have examined the temperament profiles of children with ASD, and increasing evidence is demonstrating it to be a potentially useful endophenotype in very young children with ASD.  Temperament has been demonstrated in the developmental literature to be related to psychobiological traits, which may be implicated early on in children at risk for ASD. 

Objectives: The current study compared temperament profiles between toddlers showing significant early signs of autism and toddlers with speech or other developmental delays. 

Methods: 817 toddlers born in 2006 were screened at a local pediatric clinic using the M-CHAT and CSBS.  Of those who screened positive (after phone follow-up) on the questionnaires, 32 were brought in for an in-person screening with the ADOS, Mullen Scales of Early Learning, and Vineland Adaptive Behavior Scales-II.  Seventeen parents also completed the Carey Temperament Scales, before they were told the results of the in-person screening.  Seven of these were determined to be showing significant early signs of autism (EA) based on in-person screening measures and clinical judgment. The remaining 8 were determined to be negative for early signs of autism, but had speech or other developmental delays (DD).  The EA and DD groups were analyzed for differences in temperament domains (i.e. Approach, Adaptability, Intensity, Mood, Persistence, Distractibility, Threshold, Activity, Rhythmicity).  The Mullen Scales were included as a covariate.   

Results: A MANCOVA using the Mullen Scales Early Learning Composite (ELC) as a covariate was conducted. The MANCOVA did not indicate a main effect of group (EA versus DD) for the temperament domains (F(9,4) = .814, p = .6).  However, when ELC was covaried the EA group demonstrated a trend toward lower scores on Adaptability (EA: M = 3.6, SD = 1.3; DD: M = 4.1, SD = .6; F(9,1) = 3.5, p <.10) and Approach (EA: M = 3.3, SD = .9; DD: M= 4.04, SD = .5; F(9,1) = 2.6, p <.10).   

Conclusions: The present study found that among toddlers who screened positive on the M-CHAT or CSBS-ITC, those who also screened positive by clinical judgment may be more likely to have parental reports of less social approachability toward others, as well as less adaptability, compared to those who screened negative by clinical judgment.  This may suggest that temperament characteristics could be helpful in understanding the early presentation of autism, especially from parental reports.  Along with social, cognitive, and other domains, this may help us identify early endophenotypes of autism.