Stereotypic and Repetitive Behaviour in Individuals with Autism Spectrum Disorder: a Systematic Review of Intervention Practices

Background: A demonstration of stereotypic and repetitive behaviour (SRB) is one of three criterion required to receive a diagnosis of autism (APA, 2000). Behaviours may include restricted interests, repetitive movements or intense, constant interest in parts of an object (APA, 2000). When SRBs become so intrusive that they affect a child's ability to attend, learn and interact they require intervention. A systematic review utilizes a replicable procedure and provides unbiased and transparent quantitative and qualitative information. Evaluation of studies that use a systematic methodology aid in determining which interventions are supported by evidence to ensure that best practices are put forth for use by intervention providers. This form of review has yet to be completed in the area of SRB interventions for individuals with autism. Objectives: The objectives of the review were to: 1) identify the intervention practices used to reduce SRBs in individuals with ASD; 2) describe the participants, outcomes and intervention methods; 3) evaluate the methodological quality of the empirical evidence. Methods: A systematic search of 20 electronic databases was completed. Sixty-four studies were included after examination by two independent reviewers who applied the following inclusion criteria: 1) interventions focusing on SRBs; 2) participants of any age diagnosed with Autism, Asperger's Syndrome or Pervasive Developmental Disorder; 3) study design was either a randomized control trial (RCT), quasi group or single case experimental design; 4) published from the year 1994 onward in English. Methodological quality was assessed. Studies underwent a quality assessment to evaluate aspects of participant selection/attrition, comparison groups, design, application of the intervention, and analysis (AACPDM, 2004; Gersten et al., 2005; Jadad et al., 1996). Data was systematically extracted and reported in evidence tables. Further, studies were classified according to the continuum of interventions for ASD including biologically based, behavioural, therapy based, reinforcement based, sensory, exercise based, restricted interests as a component of the intervention, developmental and other interventions (Roberts & Prior, 1996). Characteristics of these studies were summarized using descriptive statistics and reported by category of intervention. Results: The majority of the participants were American, Caucasian, school-aged males with a diagnosis of autism. A wide range of SRBs were examined including repetitive movement, vocalizations, self-injurious behaviours and echolalia typically in school or home settings. Overall, the methodological quality of the RCTs (n=14) was moderate to strong. Quasi group designs (n=7) were found to be of low quality and single case designs (n=43) were of moderate quality. Interventions evaluated using group designs were primarily biologically based, while single subject interventions were reinforcement and therapy based. Short term positive effects have been demonstrated for the majority of interventions however, no intervention has enough empirical support to be considered an evidence-based practice (Reichow, Volkmar & Cicchetti, 2007). Conclusions: Results indicate a variety of interventions are in place; however, only preliminary evidence exists to support their implementation. Increased methodological rigor is required in future research to determine evidence-based practices.