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The Behavioural/Developmental Continuum of Interventions for Autism Spectrum Disorders: A Systematic Review


Decade. 1970's. 1980's. 1990's. 2000-2007. Not reported. Single Case. Case Control. Before/After. Retrospective. RCT/CCT. 1960's. Applied Behaviour Analysis ... – PowerPoint PPT presentation

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Title: The Behavioural/Developmental Continuum of Interventions for Autism Spectrum Disorders: A Systematic Review

The Behavioural/Developmental Continuum of
Interventions for Autism Spectrum Disorders A
Systematic Review
  • Many Faces of Childhood Well Being The Early
  • November 30, 2007
  • Veronica Smith

The need for a systematic review Quantity of the
The need to systematically review autism
intervention Cost
(Ganz, 2007)
Previous Reviews
  • Review of reviews
  • 30 reviews on the effectiveness of behavioural
    and developmental interventions
  • 51 published after 2004 2 published before 2000
  • Focus varies (i.e., most focus on one
    intervention type or core behaviour of autism)
  • 83 of the reviews suffered from one or major
    methodological quality concerns
  • Therefore, the reviews are
  • vulnerable to bias that compromises their
  • need to be interpreted with caution
  • Krebs, J., et al., under review 2007

Purpose of our Systematic Review
  • 1 To identify
  • The efficacy and effectiveness studies of
    interventions for children with autism
  • 2 To describe
  • Participant characteristics, interventions,
    settings, and outcomes
  • 3 To evaluate
  • Methodological quality of the studies and the
    quality of the evidence

Methods Data Sources
  • Comprehensive searches of 22 electronic data
    bases of medical, educational, and psychological
    literature up to May 2007.
  • Other sources included hand searches, reference
    tracking, contact with authors, and contact with

Methods Review Methods
  • Included studies
  • Design
  • Clinical trials (RCT or CCT)
  • Observational analytic studies (retrospective or
  • Intervention
  • Any behavioural or developmental intervention for
    individuals diagnosed with ASD
  • Published in English
  • 2 independent reviewers assessed study relevance,
    extracted the data, and assessed the
    methodological quality of the studies

1 Identify Included Studies
86 Clinical trials 14 Retrospective or
prospective cohorts
2 Describe Types of Interventions
2 Describe ABA (31 studies)
  • Lovaas style therapy (UCLA Young Autism Project)
    or Intensive Behavioural Intervention or based or
    Discrete Trial methodology
  • Participants total 770 median 20 per study
  • 27 included toddlers, 12 included school age 4
    included adolescents 1 included adults
  • Only 6 studies indicated ethnicity
  • 13 reported autism severity individuals with
    severe symptoms were included in 7 studies 4
    studies limited participants to mild-moderate 13
    reported verbal ability 3 excluded nonverbal
  • Setting community, home, clinic, research
    facilities, and school
  • Outcomes 60 reported statistically significant
    results that favoured ABA therapy compared to

2 Describe Contemporary ABA (12 studies)
  • Discrete trial and naturalistic procedures (e.g.,
    natural reinforcers, incidental teaching)
  • Participants 573 total median 36 per study
  • 9 included toddlers 8 included school age 1
    included adolescents
  • 3 studies indicated ethnicity
  • 2 studies reported level of severity 2 studies
    included only verbal participants and 1 study
    included both verbal and non-verbal
  • Settings
  • Community, clinic, and school
  • Outcomes 100 of the studies reported
    statistically significant results that favoured
    Contemporary ABA

2 Describe Developmental Interventions (12
  • Application of developmental principles child
    centered examples of techniques imitative
    interaction, DIR, responsive teaching
  • Participants 256 total median 20 per study
  • All included toddlers 6 included school-age
  • 8 studies described ethnicity
  • Majority of studies did not report autism
    severity 2 studies included only verbal 6
    included verbal and non-verbal
  • Settings
  • Community setting, school, clinic, and research
  • Outcomes 83 of the studies reported
    statistically significant results that favoured
    developmental interventions

3 Evaluate Quality Scales
  • Group Research Quality Indicators
  • Clear description of participant characteristics
  • Description of intervention and interventionist
    (plus measurement of treatment fidelity)
  • Description of comparison group condition
  • Outcomes clearly described
  • Statistical analysis (e.g., missing data
    analysis) and results reporting (e.g., effect
    sizes and confidence intervals)
  • Randomized control trials
  • Need to follow accepted randomization procedure,
    and provide a description of dropouts and

Quality Scales Used
  • Jadad
  • 7 items (only five used for those studies that
    did not report using randomization)
  • Other scales used partially
  • Schultz Concealment of Treatment Allocation
    Schultz et al. (1995)
  • Chalmers et al. (1981)
  • Detsky et al. (1992)
  • Smith et al. (2007)

3 Evaluate Quality of Studies
  • Generally, across all the criteria, the quality
    of the studies was poor
  • Significant threats to validity in every major
    category of quality
  • 83 failed to describe the participants
    adequately to replicate the sampling procedure
  • Quality of reporting of intervention variable
    32 monitored fidelity
  • Less than half (43) reported independent outcome
  • 54 reported sources of funding

3 Evaluate Comparisons across the studies
  • Five comparisons were possible due to variations
    in type of intervention, comparison groups, and
    outcomes of interest (i.e., only 13 of 101
    studies used)
  • Two with clinically significant findings
  • High vs low intensity Lovaas favours high
    (outcome intellectual functioning)
  • Lovaas vs Special Education favours Lovaas
    (outcomes intellectual functioning, adaptive
    behaviour, communication, overall language, and
    expressive language)
  • (NB poor quality of studies and limited number
    of groups decreases generalizability of these

  • Researchers
  • Participant sampling
  • Homogeneity vs sample size
  • Intervention description
  • Treatment manuals
  • Fidelity
  • Comparison groups
  • Consider the inclusion of standard care as a
    treatment in the control group (i.e., treatment
    that is normally given)
  • Systematic use of outcomes

  • Practitioners Policy Makers
  • Provision of intervention that addresses the core
    symptoms for autism is self evident
  • Many practices reported in the research have been
    demonstrated effective
  • Should be employed with caution and closely
    monitored until a greater accumulation of
    evidence is present

Next steps
  • More work to be done
  • Systematically review the evidence contribution
    of single case research
  • Example of single case quality assessment
  • Reichow et al. (in press)

  • Funders
  • Alberta Centre for Child, Family and Community
  • Collaborators
  • Alberta Centre for Child Health Evidence
  • Principal Investigators
  • Brenda Clark, M.D.
  • Veronica Smith, Ph.D.
  • Research Team
  • Maria Ospina, M.Sc. (Project Manager)
  • Lisa Hartling, M.Sc.
  • Mohamed Karkhaneh, M.D.
  • Jennifer Seida, B.H.Sc.
  • Lisa Tjosvold, M.L.I.S.
  • Denise Thomson, M.B.A
  • Janine Odishaw, Ph.D.
  • Ben Vandermeer, M.Sc.