Variables affecting outcome of early intervention in autism spectrum disorder

Heterogeneity in autism spectrum disorder (ASD) is reflected in the child's characteristics, including clinical variability in the severity of autism symptoms, cognitive ability, and language skills. Also, substantial individual differences are apparent about treatment outcomes. The effects of early intervention in ASD constitute one of the important questions ASD researchers face today. To what extent do factors such as child and family characteristics, intervention approach, and specific treatment components, influence outcome? This review focused on which preintervention factors better predicted outcome in each of the different outcome measures used most frequently in ASD research, including autism severity, cognitive ability, and adaptive behavior skills. For outcome in autism severity, predictors included child's baseline age, cognitive ability, autism severity, and the type of treatment approach used. For cognitive gains, predictors included baseline autism severity, maternal and educational level, and the type and intensity of the treatment. For outcome in adaptive behavior skills, predictors included baseline cognitive ability, autism severity, maternal age, and the treatment approach and intensity. Future studies in this field should expand the scope of factors, look for more specific behaviors, and investigate the interplay between a child's characteristics, familial factors, and various treatment aspects that might affect the outcome of the intervention.