Behavioral Approach Characteristics and Variability In Onset Patterns and Symptom Presentation In ASD Siblings

Background:  Prospective research from longitudinal studies with infant siblings of children with ASD has suggested that timing of symptom onset may vary for children who later receive the diagnosis with some children showing ASD profiles by 14 months of age.  Both retrospective and prospective studies have suggested that variability in onset may be in part associated with individual differences in social approach-avoidance tendencies, where children with parent-reported approach tendencies are identified later (after 14 months) than their withdrawal inclined counterparts. Additionally, previous research with ASD children has shown associations between variability in behavioral approach characteristics and comorbid emotional-behavioral symptoms, such that children with approach biases showed greater comorbid internalizing impairment when compared with withdrawal-oriented children.

Objectives:  Associations between clinician-observed behavioral approach tendencies and variability in onset patterns and symptom presentation in ASD siblings were examined. Consistency with parent-report data was assessed when available.

Methods: Early versus Later onset profiles were determined for 49 subjects based on best estimate clinical judgment (CJ) ratings completed at each study time point (14, 18, 24, 30, and 36 months). Children with CJ of ASD at or before 18 months of age were classified as “Early;” all others were classified as “Later.” Behavioral Approach (BA) characteristics were measured using the Communication and Symbolic Behavior Scales, Developmental Profile (CSBS-DP) at 14 months. A BA composite was computed by adding total scores for coded Gaze Shifts, Shared Positive Affect, and Initiating Joint Attention behaviors. High versus Low BA was indicated based on a median split of the group. Additional data on BA characteristics and comorbid symptoms were gathered via parent report on the CSBS-DP and the Behavioral Assessment System for Children – Second Edition. 

Results: Results of a Chi Square analysis examining the association between High vs. Low BA and Early vs. Later onset patterns indicated significant differences for onset groups, X² (49) = 7.23, p < .01. Examination of the cross-tabulation indicated that the Later group consisted of significantly more subjects with High BA profile (15 High/7 Low), while the Early group consisted of more subjects with the Low BA profile (19 Low/8 High). However, parent report of BA characteristics did not show a significant relation to onset pattern. Results of a MANOVA examining the association between BA profiles and parent-reported comorbid symptoms at 36 months were not significant.

Conclusions: These data support previous findings showing an association between behavioral approach characteristics and onset patterns in children with ASD. Children with High BA tendencies were more often categorized as ASD Later when compared with children with Low BA tendencies. The lack of convergence with parent report data on behavioral approach tendencies may be due to limitations of the measure of approach, and/or caregivers’ lack of sensitivity to variability on this dimension at 14 months of age. Contrary to previous literature, behavioral approach tendencies were not associated with later comorbid symptoms. This may have been due to lack of sufficient longitudinal data on symptoms.