Rethinking the idea of late autism spectrum disorder onset

Area of Science:

• Developmental Pediatrics
• Neurodevelopmental Disorders
• Autism Research

Background:

• Autism spectrum disorder (ASD) diagnosis often occurs after age 2, termed late-onset ASD.
• Understanding early differences between early and late-diagnosed ASD is crucial.

Purpose of the Study:

• To compare clinical phenotypes of early-diagnosed ASD versus late-diagnosed ASD in toddlers.
• To identify early indicators of ASD, regardless of diagnostic timing.

Main Methods:

• Longitudinal study of 273 toddlers from 12 months to age 3.
• Utilized standardized assessments, eye-tracking, and observational measures.
• Compared early and late-diagnosed ASD, language-delayed, and typically developing groups.

Main Results:

• Both early and late-diagnosed ASD groups showed early social communication delays.
• Early-diagnosed ASD showed greater initial impairment; late-diagnosed ASD showed slower language acquisition.
• Similar early social communication deficits were observed in both ASD groups.

Conclusions:

• ASD's social communication impairments are present very early, irrespective of detection.
• Current diagnostic methods may miss early signs of ASD.
• Development of more sensitive ASD detection tools is necessary.