Cognitive Development in Children with Autism Spectrum Disorder and the Moderating Role of Intervention and ASD Persistence

This study examined whether Bayley Scales of Infant and Toddler Development-III (Bayley-III) standardized cognitive scores from toddlers diagnosed with autism spectrum disorder (ASD) predict intellectual quotient (IQ) at early school age and whether ASD persistence or interventions received moderate this relationship. Children diagnosed clinically with ASD at 12-36 months underwent research assessments at 5-7 years. Of 212 children diagnosed as toddlers, 133 continued to meet DSM-5 ASD criteria based on current functioning at school age ("persistent ASD"), and 79 did not ("non-persistent ASD"). A moderate positive correlation was found between baseline cognitive scores in toddlerhood and school age IQ (r (210) = 0.45, <i>p</i> < 0.001). Children with baseline cognitive scores < 70 showed greater variation in school age IQ compared to those with baseline scores > 85. Non-persistent ASD status was associated with a higher rate of cognitive change from toddler to school age (S_diff = 15.044; z = 4.432, <i>p</i> < 0.001). Overall, 94.3% of the sample received ASD-specific interventions. There was no relation between hours of ASD-specific interventions and change in cognitive trajectories for children with non-persistent ASD and an inverse relationship for children with persistent ASD.