Repetitive Behaviors In Young Children with Autism: Specificity and Stability

Background:  

Research indicates that the type and severity of restricted and repetitive behaviors and interests (RRBs) is one area of symptoms that differentiates autism spectrum disorders (ASD) from other developmental disorders (Bodfish, Symons, Parker, & Lewis, 2000; Richler, Bishop, Kleinke, & Lord, 2007; Richler, Huerta, Bishop, & Lord, 2010). The Repetitive Behavior Scale, Revised (RBS-R, Bodfish et al., 2000) has been used to examine RRBs in children with autism; however, few studies have used this tool to examine differences in RRBs among children with ASD compared with other developmental disorders and typical development. Studies have also not used this measure to examine repetitive behaviors over time in young children with autism.

Objectives:  

This study examined 1) differences in RRBs among children with an ASD, nonspectrum developmental delay (DD), and typical development (TD) and 2) RRBs over time in children with autism.

Methods:  

Participants included age-matched groups of 106 children with autism (mean age = 4.03 years, +/-1.10), 39 PDD-NOS (mean age = 3.86 years, +/- 1.18), 23 nonspectrum DD (nonverbal developmental quotient below 80, mean age = 3.89 years, +/-.86), and 44 TD (mean age = 3.55 years, +/-1.13). To date, 56 children in the autism group (mean age =5.45 years, +/-1.22) have Time 2 data (mean time = 1.26 years, +/-.26 years). All participants completed a cognitive measure, from which a nonverbal development quotient (NVDQ) was calculated, and the Autism Diagnostic Observation Schedule (with the Social Affect “new” algorithm score used for this study). RRBs were examined using the RBS-R, a parent report measure that includes 5 subscale scores: Stereotypic Behavior, Self-Injurious Behavior, Compulsive Behavior, Rituals/Sameness Behavior, and Restricted Interests. Measures were repeated at Time 2 in the autism group.

Results:  

Preliminary results of ANCOVA (controlling for NVDQ) revealed that children with autism and PDD-NOS scored significantly higher than TD on the RBS-R total score and all subscales except Self Injurious Behavior; and significantly higher than DD on the total score and 3 of 5 subscales (stereotypic behavior, compulsive behavior, restricted interests). No significant differences were found between autism and PDD-NOS. In the autism group (N=56), repeat measure t-tests revealed no significant differences between Time 1 and Time 2 RBS-R total and subscale scores. Hierarchical regression analyses found that RRBs at Time 1 significantly predicted RRBs at Time 2, and age, NVDQ, and Social Affect at Time 1 did not contribute significantly to the model.

Conclusions:  

Preliminary analyses found the RBS-R to be a useful measure in finding that certain types of RRBs differentiate children with ASD compared to DD, and almost all RRBs are more common in ASD compared to TD. Additionally, results indicated that over a one year timeframe, RRBs overall were highly stable in children with autism. This study provides information about the types of RRBs that may be specifically associated with ASD as well as the stability of RRBs in young children with autism.