A review of 25 major studies investigating the value of sensory integration therapy (SIT) for autistic children has concluded that this most popular of therapies has no scientific support.
Only three of the 25 studies found benefits from SIT, and these three all had serious methodological flaws. Eight of the studies found mixed results, while 14 studies reported no benefits. Many of the reviewed studies had serious methodological flaws.
It has been suggested that SIT may even be harmful, in that it may lead to an increase in undesirable behavior. Regardless, by taking up time that could otherwise be spent on effective therapies, the use of SIT is not recommended.
The only scientifically valid treatment and intervention for individuals on the autism spectrum is said to be applied behavior analysis, in which, unfortunately, few are trained. With applied behavior analysis, the therapist teaches children age-appropriate skills and offers systematic, repetitious positive reinforcement for desired behaviors.
 Sensory integration therapy for autism spectrum disorders: A systematic review. Research in Autism Spectrum Disorders [Internet]. 2012 ;6(3):1004 - 1018. Available from: http://www.sciencedirect.com/science/article/pii/S1750946712000074