Introduction: Autism spectrum disorder (ASD) is one of the neurodevelopmental disorders of childhood, but small percentage of children with ASD are diagnosed before the age of three. The aim of this study was to investigate the psychometric properties of the Persian version of the Modified Autism Checklist in Infants.
Methods: This study was conducted on a population of toddlers from specialized centers and hospitals in Isfahan. Inclusion criteria included a diagnosis of autism, age between 18-36 months, Persian language proficiency, and parental consent. Exclusion criteria included unwillingness to participate, incomplete checklist, neurological disorders, and severe disabilities. The Persian version of the checklist was initially translated by expert translators, then reviewed, and the final version was administered to 318 toddlers.
Results: Construct validity analysis identified three underlying factors explaining 43% of the variance. Convergent validity was assessed using CHAT, PDDS, and the CHAT versions completed by doctors and parents. Diagnostic validity demonstrated the tool's ability to differentiate between typical and ASD toddlers. The omega coefficients for the reliability of the three factors were 0.920, 0.773, and 0.680, respectively. The sensitivity and specificity of the tool were higher in identifying boys with autism. The area under the ROC curve was 0.85 for girls and 0.90 for boys. Cut-off points were determined to be 6 for girls and 4 for boys.
Conclusion: The M-CHAT-R/F has desirable psychometric properties, although some items require revision. The tool performs well across different gender groups and can be effectively used for early diagnosis of autism in toddlers.