Restricted, Repetitive Behavior: A Comparison of Children with Autism Spectrum Disorder, Obsessive-Compulsive Disorder, Down Syndrome and Two Typical Control Groups

Background:  Restricted, repetitive behavior (RRB) is a core feature in a wide variety of neurodevelopmental and neuropsychiatric  disorders including autism spectrum disorders (ASD), Tourette syndrome (TS), and Obsessive-Compulsive Disorder (OCD), among many others. RRBs also vary as a function of developmental status, and children with Down syndrome (DS) for example, exhibit repetitive behavior commensurate to their mental age status. Few empirical efforts have compared the rates of RRB in various groups of children representing a range of neurodevelopmental or neuropsychiatric disorders .

Objectives:  We aim to examine rates of RRB in children with the following diagnoses: ASD, OCD, Down syndrome, as well as two groups of neuro-typical children – one matched to the Mental Age, another to the Chronological Age of the DS group. We examine the clinical sensitivity of the Childhood Routines Inventory (CRI) with children of varying diagnostic status

Methods:  : Parents of two-hundred fourteen children and adolescents ranging in age from 1 to 14 (1 to 21 years for the DS group) completed the CRI. Participants were recruited from a university-based clinic in the Northeast (the OCD group (n=42)) as well as sites in the Southeastern US (the DS (n=44), ASD (n=41) and neurotypical groups (CA match n=42; MA match n=45).  The CRI is a 19-item parent-report inventory assessing restricted, repetitive behavior. The CRI was normed on over 1500 families of typically-developing children yielding a two-factor structure—Repetitive Behavior and “Just Right” behavior (Evans, Leckman, Carter, Reznick, Henshaw, King & Pauls, 1997). Subsequently, factor analyses were performed on a sample of 319 children with neurodevelopmental disorders, and the factor structure yielded al third factor – sensory sensitivities. Whereas other measures of RRB tend to yield restricted ranges in typically-developing children, the CRI is normally distributed in typically-developing samples, allowing for more rigorous comparisons of typical and clinical samples.

Results:  ANOVA compared the means of three CRI scales across diagnostic groups. For the Just Right factor groups differed significantly (F(4,204)=14.02, p < .0001). Post hoc tests revealed that the ASD group had significantly higher scores than all other groups.  Similar results emerged for the Repetitive Behavior subscale (F(4,200)=40.72, p< .0001): the ASD group was significantly higher than all other groups, followed by DS, OCD and then CA-matched typical children.  Only the ASD group differed from all other groups on the sensory sensitivities factor (F(4,205)= 17.18, p<.0001).

Conclusions:  The factor structure of the CRI is best represented by a 3-factor structure in children with neurodevelopmental disorders. The three factors differentiate children with ASD from other diagnostic groups, as well as from MA- and CA-matched typical children. The CRI provides a useful clinical and research tool for assessing restricted, repetitive behavior in both typically and atypically-developing children.