Though limited, findings of existing studies suggest that preschool children with autism exhibit cognitive and functional improvement when receiving behavioural intervention with applied behavioural analysis for approximately 20 hours per week or more. It is not clear, however, which subset of children with autism derive the most benefit, which components of therapy are integral to positive outcomes, whether similar results would be observed in older children with autism, whether there are definable long term functional benefits, or whether reported gains in IQ translate into happier people with greater functioning in the community.
It is important for policy makers, program developers and clinical researchers to consider identifying pre-treatment characteristics of those receiving therapy, measuring treatment fidelity, evaluating progress in therapy to determine whether therapy is or continues to be of benefit, and comparing the value of early intensive behavioural therapy to other early interventions for autism.
Methodological flaws in the primary studies that were examined in reviews suggest that standard measures for assessment, continued evaluation of progress, and long term functional outcomes are required in future study design. Improved research methods would provide more reliable evidence about therapeutic effectiveness and would assist in the planning of individualized treatment programs aimed at more successful outcomes.