Background: Autism spectrum disorder (ASD) is one of emerging neurodevelopmental disorder on 20^th century with a remarkable increasing prevalence. Pusponegoro and pediatric neurologists in Indonesia based on their clinical experience observed that sensory integration occupational therapy (SI-OT) might be useful as ASD treatment for young children especially under 5 years old.

Objective: To evaluate the influence of SI-OT in reducing negative behavior of children ages 2 to 5 years with ASD.

Methods: The study conducted in two clinics. The study population were new ASD children ages 2 to 5 years. Subject were collected with consecutive sampling. Behavior profile were assessed with Aberrant Behavior Checklist (ABC)-2 before and after SI-OT twice a week for 12 weeks. Analysis of normal value with t test and Wilcoxon test for unequally distributed value.

Results: A total of 42 ASD subjects were studied, 50% were 3 years, and boys to girl ratio were 5 to 1. The highest negative behavior was hyperactivity 23,61 (SD 8,91) followed by social withdrawal 16,81 (SD 8,16), and irritability 11,43 (SD 6,99). Stereotypic median was 5,25 and inappropriate speech 2,00. After SI-OT, all negative behavior decreased significantly p<0.001. Hyperactivity decreased to 12,71 (SD 8,36) about 53,8%, social withdrawal to 7,94 (SD 6,18) 47,2%, irritability to 6,62 (SD 4,99) 57,9%, and median of stereotypic 19,0% and inappropriate speech 50%.

Conclusions: We found that SI-OT twice a week for 12 weeks significantly reduced negative behavior of young ASD children especially ages 2 to 5 years.