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The Behavioural/Developmental
Continuum of Interventions for Autism Spectrum Disorders: A
Systematic ReviewMany Faces of Childhood Well
Being: The Early Years
November 30, 2007
Veronica Smith
The need for a systematic review: Quantity of the evidence
0
100
200
300
400
500
600
Number of Studies
1960's 1970's 1980's 1990's 2000-2007
RCT/CCT
Retrospective
Before/After
Case Control
Single Case
Not reported
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 validity; • 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 experts
Methods: Review Methods
• Included studies:– Design
• Clinical trials (RCT or CCT)• Observational analytic studies (retrospective or prospective)
– 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
0
2
4
6
8
10
12
14
16
Number of Studies
1977 1981 1985 1989 1993 1997 2001 2005
Year of Publication
Included Studies
8
86 Clinical trials
14 Retrospective or prospective cohorts
Applied Behaviour Analysis
30%
Contemporary ABA12%
Developmental Approaches
12%
Integrative Programs
14%
Communication-Focuses
Interventions10%
Environmental Modifications
1%
Sensory Motor Interventions
15%
Social Skills Interventions
6%
#2 Describe: Types of Interventions
Figure: 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 comparison
Figure: Types of Interventions
#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
Figure: Types of Interventions
#2 Describe: Developmental
Interventions (12 studies)– 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 facilities
– 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 withdrawals
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
assessment• 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 findings).
Implications
• 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
Implications
• 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)
Acknowledgements
Funders:
Alberta Centre for Child, Family and Community Research
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.AJanine Odishaw, Ph.D.Ben Vandermeer, M.Sc.
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