Early Behavioral Indicators of Optimality of Developmental Outcome in an ASD Risk-Enriched Sample

Poster Presentation
Thursday, May 2, 2019: 11:30 AM-1:30 PM
Room: 710 (Palais des congres de Montreal)
R. Landa1 and M. Tahseen2, (1)Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore, MD, (2)Kennedy Krieger Institute, Baltimore, MD

Chronological transition into the second year is characterized by developmental transitions in communication, social engagement, and play. Early experience across such domains during this developmental transition could entrain a distributed system of social-cognitive and symbolic processing, possibly optimizing development and reducing degree of later manifestation of autism spectrum disorder (ASD) symptomatology.


To define behavioral profiles at 14 months that differentiate ASD symptomatology level at age 2 to 3 years. Hypothesis: Profiles defined by early language, gesture, social, and repetitive/restricted behavior patterns will be associated with later ASD symptomatology level.


Children at low and high familial risk (LR N=98, HR N=323) for ASD were enrolled in a prospective, longitudinal study and assessed at mean age 14.51 months (sd=.74), with 419 having outcome assessment (mean age=36.17 months; sd=2.53).

Clustering variables at 14 months: Mullen Scales of Early Learning Expressive Language (EL) T score (Mullen, 1995), Communication and Symbolic Behavior Scales Caregiver Questionnaire (CSBS CQ) Object Use and Social composite standard scores (Wetherby & Prizant, 2002), Autism Diagnostic Observation Schedule (ADOS) Repetitive and Restricted Behavior section total score (RRB; Lord et al., 2002). Post hoc analysis variables: CSBS CQ Emotion & Eye Gaze, Communication, and Gestures subscale standard scores; ADOS Calibrated Severity Score (CSS); Clinical judgment of ASD+/ASD-; Mullen EL T scores.

Hierarchical agglomerative cluster analysis, with clustering determined by Ward’s (1963) method was performed. Squared Euclidean distance served as the similarity measure. Variables were standardized to control for unequal scaling. To determine the optimal number of clusters to retain, we used: visual examination of the dendogram, Mojena’s Rule One, and examination of fusion coefficients (Lorr, 1983; Milligan & Cooper, 1985; Mojena, 1977). A MANOVA was conducted to compare the retained clusters on the four clustering variables. Additional post-hoc analyses used ANOVA and chi square.


A 2-cluster solution was most optimal; Jaccard coefficients indicated high stability for both clusters (>.70). Cluster 1 (n=300) scored significantly lower on all clustering variables at 14 months than Cluster 2 (n=120) (Table 1). A significantly greater percentage of toddlers in Cluster 1 (hereafter, At-Risk) were identified as ASD+ at outcome, X2(1, N=339), 18.68, p<.001, compared to those in Cluster 2. At age 36 months, toddlers in At-Risk Cluster had higher ASD symptomatology (ADOS CSS) and lower EL scores than Cluster 2 (p’s<.001). Within the At-Risk Cluster, toddlers with ASD+ outcomes scored significantly lower than non-ASD toddlers at 14 months on CSBS CQ scales of Emotion and Eye Gaze, Gestures, and Communication (p’s<.001).


A combination of more advanced spoken language, play, and social development, along with reduced RRB levels, at age 14 months appear to define an optimality profile associated with low levels of ASD symptom manifestation at age 36 months. Early coherence within and across these domains may facilitate continuous improvement in efficiency and combinations of information processing that support enhanced learning (Hunt, 1999) (and reduced ASD symptomatology) through age 36 months. Thus, exposing infants to early enriching experiences is emphasized, especially for younger siblings of children with ASD.