Measuring Restricted Interests and Repetitive Behaviors in Infant Siblings at-Risk for ASD: Comparing HOME-Setting Versus Clinic Performance of 12 Month Olds

Background:

Approximately 20% of younger siblings of children with ASD are at an increased risk for developing ASD (Ozonoff, 2011). According to DSM-5, symptomatology involves restricted, repetitive patterns of behavior (RRB); however, these indicators are only more recently examined in younger siblings. During the second and third year, studies have demonstrated repetitive hand/finger mannerisms become more pronounced among children with ASD and less pronounced among children with developmental delays (DD) and typical development (TD). Zwaigenbaum et al. (2013) summarized prospective studies, in comparison to retrospective studies, more consistently identified RRB as early as 12 months in children with subsequent ASD diagnosis, citing atypical and repetitive behavior with objects and visual exploration of objects. Further, Stronach & Wetherby (2012) examined RRB among toddlers (mean age 20 months) in clinic and home settings, identifying higher presence of RRB in clinic, given the nature of structured probes and repeated presentations of objects.

Objectives:

This study examines the relationship between home observation and clinical assessment of RRB among 53 (projecting 70 by May 2017) 12-month old infants considered at-risk for ASD, given sibling status.

Methods:

High-risk, 12-month infant siblings were seen for communication assessments as part of a federally-funded longitudinal study examining risk and resilience. The assessment battery included two samples of early social-communication behavior: Communication & Symbolic Behavior Scales (CSBS-DP; Wetherby & Prizant, 2002) and a video-recorded home observation. The Systematic Observation of Red Flags of ASD (SORF) is an ASD-specific screening instrument that captures red flags related to social-communication and interaction and RRBs. The SORF was used to rate early symptomatology within clinic (Clinic-SORF) and home (Home-SORF) settings. Pearson’s correlation examined linear association between red flags observed in the Clinic-SORF compared to the Home-SORF. Paired t-tests examined differences between number of social-communication and RRB red flags observed using Clinic-SORF and Home-SORF. Further, differences in four specific behaviors of interest from the RRB domain were explored: (1) repetitive movements with objects, (2) repetitive body movements/posturing, (3) sticky attention to objects, and (4) unusual sensory exploration/excessive interest in sensory aspects of environment.

Results:

Pearson’s correlation indicated significant association between total observed red flags obtained from home and clinic settings (r= 0.382; p<0.01). There was no significant difference between the number of Social-Communication red flags observed in the Home-SORF and Clinic-SORF. However, there were significantly more RRB red flags observed on the Clinic-SORF compared to the Home-SORF. With further analysis at the item level in RRB domain, Clinic-SORF revealed a significantly higher score than Home-SORF for the following items: repetitive movements with objects (p<0.001), sticky attention to objects (p<0.001), and unusual sensory exploration/excessive interest in sensory aspect of environment (p<0.001). There was no difference between Home-SORF and Clinic-SORF for repetitive body movements/posturing.

Conclusions:

Findings suggest home observation and clinic assessment highlight similar social-communication and social-interaction vulnerabilities. Significantly though, while the CSBS is primarily examining communication, structured tasks involving objects and communicative temptations may reveal increased amounts of RRB, therefore exposing earlier symptomatology and providing more quantitative assessment of red flags in this diagnostic domain.