biostudies-literatureMiller MNICHD NIH HHSNational Institute of Child Health and Human Development Intellectual and Developmental Disabilities Research CenterNIMH NIH HHSNational Institute of Mental Health665-675https://www.ebi.ac.uk/biostudies/studies/S-EPMC8480432biostudies-literatureUnknown130(6)We evaluated repetitive behavior with objects in infants at risk for autism spectrum disorder (ASD) from 9 to 36 months of age, and associations between early repetitive behavior and social engagement. Infant siblings of children with ASD (high-risk) or typical development (low-risk) were administered a task eliciting repetitive object use at 9, 12, 15, 18, 24, and 36 months of age. Infants (n = 147) were classified into 1 of 3 outcome groups at 36 months: Low-Risk Non-ASD (n = 58), High-Risk Non-ASD (n = 72), and ASD (n = 17). Behavior was coded from video for frequencies of unusual visual inspection, spinning, and rotating behaviors. Differences in unusual visual inspection were most prominent, consistent, and present earliest: At 9 months, the ASD group engaged in this behavior more frequently than both other groups, persisting through 36 months. Differences in frequencies of spinning and rotating were later-appearing, more time-limited, and/or related to familial ASD risk rather than ultimate diagnosis. Sensitivity and specificity estimates for the presence of unusual visual inspection at 9 months of age were in the moderate range (.60 and .68, respectively) for ASD versus Low-Risk Non-ASD comparisons, generally increasing over time. Unusual visual inspection at 9 months predicted 12-month social behavior controlling for 9-month social behavior, but not vice versa, with no evidence of moderation by ASD diagnosis. In summary, unusual visual inspection of objects is present and stable by 9 months of age in infants developing ASD and predicts reduced social engagement three-months later. Close monitoring of this behavior may aid early detection. (PsycInfo Database Record (c) 2021 APA, all rights reserved).Journal of abnormal psychologyRepetitive behavior with objects in infants developing autism predicts diagnosis and later social behavior as early as 9 months.PMC8480432P50 HD103526R01 MH068398R01 MH121416Miller MYoung GSBelding ATubbs ASun SOzonoff SIosif AMfalseRepetitive behavior with objects in infants developing autism predicts diagnosis and later social behavior as early as 9 months.We evaluated repetitive behavior with objects in infants at risk for autism spectrum disorder (ASD) from 9 to 36 months of age, and associations between early repetitive behavior and social engagement. Infant siblings of children with ASD (high-risk) or typical development (low-risk) were administered a task eliciting repetitive object use at 9, 12, 15, 18, 24, and 36 months of age. Infants (n = 147) were classified into 1 of 3 outcome groups at 36 months: Low-Risk Non-ASD (n = 58), High-Risk Non-ASD (n = 72), and ASD (n = 17). Behavior was coded from video for frequencies of unusual visual inspection, spinning, and rotating behaviors. Differences in unusual visual inspection were most prominent, consistent, and present earliest: At 9 months, the ASD group engaged in this behavior more frequently than both other groups, persisting through 36 months. Differences in frequencies of spinning and rotating were later-appearing, more time-limited, and/or related to familial ASD risk rather than ultimate diagnosis. Sensitivity and specificity estimates for the presence of unusual visual inspection at 9 months of age were in the moderate range (.60 and .68, respectively) for ASD versus Low-Risk Non-ASD comparisons, generally increasing over time. Unusual visual inspection at 9 months predicted 12-month social behavior controlling for 9-month social behavior, but not vice versa, with no evidence of moderation by ASD diagnosis. In summary, unusual visual inspection of objects is present and stable by 9 months of age in infants developing ASD and predicts reduced social engagement three-months later. Close monitoring of this behavior may aid early detection. (PsycInfo Database Record (c) 2021 APA, all rights reserved).2021-01-01T00:00:00Z2021 Aug2025-04-04T13:57:39.012Z2025-04-04T13:57:39.012ZS-EPMC84804323455396110.1037/abn0000692