Temperamental Features in Toddlers with ASD Are Independent of Symptom Severity

Background:  Temperament is defined as constitutionally-based aspects of behavior in the domains of reactivity and regulation (Rothbart and Bates, 1998). Temperament in toddlers with Autism Spectrum Disorder (ASD) remains largely unexplored, and information on the temperamental profiles of this cohort may shed light on their developmental patterns, heterogeneity of presentation, and treatment options. While research in this area has begun, it mainly focuses on the affective and attentional differences between toddlers with ASD and their typically developing and developmentally delayed peers (Garon, 2009; Koller, 2014). To complement previous work, this study examined the associations between temperament and autism symptom severity in a large sample of toddlers with ASD.

Objectives:  The main goal was to examine the relationship between temperamental domains of the Toddler Behavior Assessment Questionnaire-Supplemental (TBAQ-S) and the severity of autism symptoms (ADOS-G) in toddlers with ASD, thereby determining whether the TBAQ-S captures a construct independent of social features in toddlers with ASD. 

Methods:  182 toddlers with ASD (149 males) between 16 and 48 months of age (mean age = 28 months) were derived from a clinic-referred sample and received a comprehensive developmental and diagnostic assessment of cognitive, language, and social-communication skills. Prior to the testing, parents completed the TBAQ-S,  which includes three composite scales: Attention— Attentional Focusing, Attentional Shifting, Inhibitory Control, Low Pleasure, Perceptual Sensitivity; Negative Emotion—Discomfort, Sadness, Soothability/Falling Reactivity, Anger, and Social Fear; and Surgency—Positive Anticipation, High-Intensity Pleasure, Activity Level, and Social Fear (Goldsmith, 1996; Jones, 1999). Associations between the TBAQ-S and ADOS-G severity were determined.

Results:  Partial Pearson’s r correlations, accounting for chronological age, were performed between the ADOS calibrated severity scores (CSS) and the thirteen TBAQ-S subscale scores as well as the three TBAQ-S composite scale scores.  No significant correlations were found between any subscale or composite scale and ADOS severity. The three composite scales were modestly negatively correlated with CSS (Attention: r = -.12; Negative Emotion: r = -.16; Surgency: r= -.18).

Conclusions:  The findings indicate that temperamental dimensions of behavior are largely independent of autism symptomatology, indicating the unique contribution of temperament to an individual’s behavioral profile and strengthening the independent value of both the ADOS and the TBAQ-S. These results are perhaps not surprising, given that temperament captures vastly different aspects of behavior than that measured by the ADOS. Dimensions of temperament may further expand our understanding of the heterogeneity in functioning and development within the autism spectrum.