The effectiveness of applied behaviour analysis interventions for people with Autism Spectrum Disorder

Publication Details

This systematic review considers the evidence for the effectiveness of interventions grounded in the principles of applied behaviour analysis for people with autism spectrum disorder.

Released on Education Counts: April 2010

Author(s): Marita Broadstock and Anne Lethaby, New Zealand Guidelines Group.

Date Published: 19 December 2008

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Executive Summary

Background

This systematic review considers the evidence for the effectiveness of interventions grounded in the principles of applied behaviour analysis for people with autism spectrum disorder.

The Ministry of Education and the Ministry of Health (‘the Ministries’) sponsored and funded the development of a New Zealand Guideline on Autism Spectrum Disorder (ASD), a draft of which was released in December 2006. In response to comments received during consultation, the Ministries put out an open Request for Tender (RFT) (Ministries of Health and Education 2007) to undertake independent, systematic reviews of published research on the effectiveness of applied behaviour analysis interventions (ABA) for people with ASD. Two review groups were contracted by the Ministry of Education to provide parallel reviews using different methodological approaches. The findings from both reviews will be considered by the ASD cross government Senior Officials Group and where they identify implications for the current Guideline on ASD, these will be considered by the ASD Living Guideline Working Group (LGWG).

Objectives and Research Questions

The objective of the review is to consider the effectiveness of ABA-based interventions for people with ASD. 

ABA-based interventions can be defined as ‘those in which the principles of learning theory are applied in a systematic and measurable manner to increase, reduce, maintain and/or generalise target behaviours’ (Ministries of Health and Education 2007). Well-established principles and techniques of ABA include (a) reinforcement, (b) shaping, (c) chaining, (d) fading, (e) response and stimulus prompting, (f) discrimination training, (g) programming, and (h) functional assessment.

The clinical questions identified in the RFT (Ministries of Health and Education 2007) were:

To what extent are interventions and strategies based on the principles of applied behaviour analysis effective in leading to the following outcomes for people with autism spectrum disorders:

  • social development and relating to others
  • development of cognitive (thinking) skills 
  • development of functional and spontaneous communication which is used in natural environments
  • engagement and flexibility in developmentally appropriate tasks and play and later engagement in vocational activities
  • development of fine and gross motor skills
  • prevention of challenging behaviours and substitution with more appropriate and conventional behaviours
  • development of independent organisational skills and other behaviours
  • generalisation of abilities across multiple natural environments outside the treatment setting
  • maintenance of effects after conclusion of intervention
  • improvement in behaviours considered non-core ASD behaviours, such as sleep disturbance, self mutilation, aggression, attention and concentration problems.

Review Methods

A systematic method of literature searching, selection and appraisal was employed in the preparation of this report, consistent with New Zealand Guidelines Group review processes.

Systematic searches were undertaken in late June 2008 to identify relevant articles. The search was limited to articles published in the English language between 1998 and 2007, inclusive. Sources included six general bibliographic databases, 16 health technology assessment/guideline databases and citation searching from retrieved references. This was supplemented by potentially relevant references submitted to the Ministries as part of consultation regarding the draft ASD Guideline. Relevant publications referenced in material obtained in the course of our review on the topic were also identified.

Studies were included if they:

  • were primary (original) group studies with a parallel control group or were secondary research (systematic reviews and meta-analyses), where they reported on eligible interventions, had a clear review question, and used at least two searching sources;
  • evaluated interventions which were predominantly based on the principles of applied behaviour analysis;
  • considered comparators including usual care, another intervention or application of interventions;
  • reported on individuals with a diagnosis of autism spectrum disorder or where results are reported separately for this group;
  • reported on at least six participants with ASD in either intervention or comparator arm;
  • presented data on at least one standardised and/or quantitative outcome measure relevant to outcomes identified in the research question.
Research papers were excluded if they:
  • were non-systematic reviews, correspondence, editorials, expert opinion articles, comments, case reports, book chapters, articles published only in abstract form, conference proceedings, news items, unpublished work;
  • were case series, case studies, uncontrolled studies without a comparison group, or were single case experimental study designs (except where reported in included systematic reviews);
  • reported on people diagnosed with Rett’s Disorder or Childhood Degenerative Disorder;
  • did not provide separate analyses/syntheses of results for eligible interventions;
  • were not deemed appropriate to the research question or nature of review, including those reporting on outcomes solely relating to safety; the acceptability of, or ethical, economic or legal considerations relating to ABA; or the impact on persons other than those diagnosed with ASD.

Key Findings and Conclusions

  • Of 1517 articles identified by the search strategy, 43 publications were identified as eligible for appraisal and inclusion in the review. These were: 21 systematic reviews or evidence-based guidelines, and 20 primary studies (8 randomised controlled trials (RCTs), one quasi randomised study, 3 cohort studies and 8 non-randomised experimental studies). 
  • This systematic review provides consistent evidence across a range of studies of reasonable quality that interventions based on the principles of ABA can produce beneficial outcomes in young children with ASD, and appear to hold more promise when compared to eclectic/standard care approaches.
  • The majority of primary studies evaluated variations on early intensive behavioural intervention (EIBI) programmes. Evidence from two of three studies which compared interventions of similarly high intensity suggests that EIBI can improve language skills, IQ and adaptive behaviour, although individual responses were highly variable. From comparisons of programmes of varying intensity, there was insufficient evidence to recommend the optimal number of intervention contact hours, although one study found that effectiveness diminished beyond 20 hours per week. Comparisons between interventions delivered by clinic staff and those of similar intensity directed by parents (with some specialist training or supervision provided) did not reveal differences in outcomes for participants with ASD.
  • The Picture Exchange Communication System (PECS) can lead to positive effects for preschoolers and primary school children with ASD, although these may not be maintained beyond treatment. 
  • There was generally consistent evidence that video modelling can lead to positive impacts for children with ASD, and qualified support for social skills interventions generally. There was insufficient evidence to determine the effects of a range of other behavioural intervention approaches evaluated in single studies. 
  • There is consistent review evidence that behavioural interventions can reduce challenging or problem behaviour dramatically, although evidence is lacking concerning whether these effects are maintained or generalised.
  • Functional behaviour analysis conducted prior to an intervention increases its effectiveness, and there is evidence to support experimental functional analysis as a particulary effective FBA approach.
  • Identifying patterns in the study results was limited by the heterogeneity of the evidence base, reflected in varying intervention approaches, treatment intensity, comparators, study settings, sample characteristics (particularly age of participants), and outcomes.
  • This report extends and strengthens the ASD Guideline’s (Ministries of Health and Education 2008) recommendations relating to ABA. It identifies emerging evidence for superior benefits of behavioural approaches over eclectic/standard care approaches in education, treatment and managing problem behaviour for people with ASD in their early childhood. However this finding should be treated with caution as results were not always consistent, the number of studies where potential confounding factors were controlled were few, and responses to interventions between individuals were highly variable.
  • Future research is needed to maximise treatment success and the direction of available resources by identifying the specific characteristics of behavioural treatment and the individuals receiving it that lead to best results.
  • The current review’s findings should be considered in conjunction with those of an independent systematic review conducted in parallel for the Ministries that included SCED primary studies. It is recommended that the findings of this report are reviewed and updated as relevant high quality evidence emerges.