This study evaluates the effectiveness of occupational therapy using Ayres Sensory Integration® (ASI) in preschool children with autism spectrum disorder (ASD). The aim is to determine whether ASI, when added to usual individualized education program (IEP)-based education, improves adaptive functioning, goal attainment, and sensory processing.

Children aged 48 to 59 months with a diagnosis of ASD were recruited from a pediatric rehabilitation center in Istanbul, Türkiye. Participants were randomly assigned to either an intervention group receiving ASI in addition to usual care or a control group receiving usual care only.

The intervention lasted 12 weeks. Outcomes were assessed before and after the intervention using standardized measures including the Vineland Adaptive Behavior Scales-Second Edition (VABS-II), Goal Attainment Scaling (GAS), and the Sensory Profile.

The study is designed as a single-blind randomized controlled trial, with outcome assessments conducted by individuals who were not involved in the intervention.

This single-blind randomized controlled trial was conducted to examine the effectiveness of occupational therapy using Ayres Sensory Integration® (ASI) in children with autism spectrum disorder (ASD). The study was carried out in a pediatric rehabilitation center in Istanbul, Türkiye between June 2021 and January 2023.

Participants were children aged 48 to 59 months who were diagnosed with ASD according to DSM-5-TR criteria and confirmed by a licensed child psychiatrist. Additional inclusion criteria included the presence of sensory processing difficulties identified through standardized assessments. Children with prior ASI intervention, significant neurological conditions, or additional developmental diagnoses were excluded.

After baseline assessment, participants were randomly assigned using a computer-based randomization system with concealed allocation. The intervention group received ASI delivered by a trained occupational therapist in addition to usual individualized education program (IEP)-based education. The ASI intervention consisted of approximately 36 hours over 12 weeks, typically delivered as three sessions per week, each lasting about 60 minutes. The control group continued to receive usual IEP-based educational services.

Outcome measures included adaptive functioning assessed by the Vineland Adaptive Behavior Scales-Second Edition (VABS-II), individualized goal performance measured by Goal Attainment Scaling (GAS), and sensory processing evaluated using the Sensory Profile. All outcomes were assessed at baseline and after the 12-week intervention period by evaluators who were blinded to group allocation.

The primary objective of the study was to determine whether ASI provides additional benefit beyond usual care in improving functional outcomes in children with ASD.

Inclusion Criteria:

• Age between 48 and 59 months
• Diagnosis of autism spectrum disorder (ASD) according to DSM-5-TR, confirmed by a licensed child psychiatrist
• Classification of ASD based on the Turkish Version of the Gilliam Autism Rating Scale-2 (TV-GARS-2)
• Ongoing participation in an individualized education or therapy program during the study period
• Presence of sensory processing difficulties identified through standardized assessments (e.g., Sensory Profile or Sensory Integration and Praxis Test)

Exclusion Criteria:

• Previous or ongoing occupational therapy based on Ayres Sensory Integration®
• Receiving educational or therapeutic services exceeding the individualized program
• Presence of additional neurological or developmental conditions (e.g., cerebral palsy, Down syndrome)
• Known seizure disorders or other significant neurological conditions

De-identified individual participant data underlying the results reported in this study will be made available upon reasonable request to the corresponding author, in accordance with institutional policies and ethical regulations.

Data will be available beginning 6 months after publication and will remain available for 5 years.

Data will be available to researchers who provide a methodologically sound proposal and receive approval from the study investigators, in accordance with institutional and ethical guidelines.

Outcome assessors were blinded to group allocation.