Prevalence, severity and correlates of restricted and repetitive behaviours in children with autistic spectrum disorders: a cross-sectional study

Previous studies have highlighted the marked heterogenous nature and
presentation of restricted and repetitive behaviours (RRBs) displayed by
children with a diagnosis of an autistic spectrum disorder (ASD). Research to
date has focused on either prevalence or severity of RRBs in children and
most studies have neglected to use autism-specific measurements of RRBs.
This cross-sectional study attempts to address this gap in the literature.
Severity, prevalence and clinical correlates (age, IQ, adaptive behaviour and
gender) of RRBs were examined in a group of 48 children (39 males, 9
females; (age range 3:1 years- 12:10 years; mean age 7:5 years) with
confirmed diagnoses of ASDs. Children were divided into two groups (17 preschool
children and 31 primary-school children) on the basis of school
placement.
The Stanford Binet Intelligence Scales-Fifth Edition was administered to all
children and parents/guardians completed a measure of adaptive behaviour
(Vineland Adaptive Behavior Scale-Second Edition). Finally, all parents were
asked to rate their children's RRBs by completing the Repetitive Behaviour
Scale-Revised. Analyses revealed that age appears to be a factor in the
phenomenology of RRBs in autistic spectrum disorders. With the exception of
compulsive behaviours (which appear to become more severe and more
prevalent with age), RRBs were rated as becoming more severe but not more
prevalent as children get older. No significant association was found between
RRBs and IQ although lower functioning children (IQ<69) were rated as
displaying more 'low-level' RRBs (Self-injurious behaviours). Finally, no significant relationship was found between adaptive behaviour or gender and
repetitive behaviour, nor were any associations found in terms of prevalence
or severity. Results of this study highlight the complexity, diversity and
heterogeneity of RRB symptoms in children with ASDs and provides further
evidence for a much-needed re-categorisation and re-definition of the autism
phenotype.
Keywords: autistic spectrum disorders, restricted and repetitive behaviours,
prevalence, severity, clinical correlates, triad of impairment.

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