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.