Intensive Behavioural Intervention for the Treatment of Autism Spectrum Disorder in Preschool and School Age Children: A Systematic Review and Meta-Analysis

Abstract

Intensive Behavioural Intervention (IBI) is one of the most widely used treatments for children with an autism spectrum disorder (ASD). While IBI has been recognized as the treatment of choice for very young children with an ASD, its sensible use among school age children is a matter of dispute. The aim of this thesis was to determine the clinical effectiveness of IBI, as compared with no treatment or treatment-as-usual, for the management of cognitive functioning and adaptive skills in preschool and school age children with an ASD, as well as to examine predictors of treatment response. Peer-reviewed, English language publications were identified using MEDLINE, EMBASE, PsychINFO, CINAHL, and ERIC from 1995 to September 1, 2014. Grey literature and reference lists of published papers were also searched for relevant records. Retrieved citations were screened by two independent reviewers, and data extraction was performed by a single reviewer with verification by a second reviewer. The methodological quality and procedural fidelity of included studies was assessed by one reviewer, and a subset of included studies were pooled in a random-effects meta-analysis using the standardized mean difference (SMD) effect size. A total of 24 unique studies were selected for inclusion in this review, comprising a total of 1,816 participants. Findings revealed that IBI improves full-scale IQ (SMD ES = 0.66, 95% CI 0.46 to 0.85, p<0.00001; 13 studies) and adaptive skills (SMD ES = 0.57, 95% CI 0.33 to 0.82, p<0.00001; 12 studies) in preschool and school age children with an ASD, with seemingly higher clinical benefits in children aged under 4 years at intake. Better outcomes with IBI are predicted by children’s relatively younger age, increased cognitive and adaptive ability, as well as a milder severity of symptoms at treatment entry. Results warrant careful interpretation in light of several methodological limitations and inadequate monitoring of procedural fidelity.