The relationship among early functional milestones and core deficits in Autism Spectrum Disorder

Background: Autism Spectrum Disorder (ASD) is now the highest among the developmental disabilities in the United States, with recent statistics estimates of 1 in every 54 children. While growing attention on the early intervention services is warranted, what is not well understood is the relationship between the core deficits of ASD and the early functional skills in young children with ASD. Objectives: The primary objective of this study was to determine the relationship between early developmental functional skills and behavioral outcomes in the core deficits of ASD. The secondary objective was to determine if the onset of early developmental functional milestones were related to age of diagnosis. Methods: The current study is a secondary data analysis of the Simons Foundation Powering Autism Research for Knowledge cohort from the Simons Foundation Research Initiative (SFARI). Study objectives were examined using multiple linear regression analyses. To address the first objective, independent analyses were conducted for each behavioral subscale (Communication, Repetitive Behavior, Atypical Behavior, Social Reciprocity, and Peer Interaction). For the second objective a linear regression analysis was conducted to determine the relationship between core deficits and age of diagnosis. Results: Multiple early functional milestones were significantly associated with current communication deficits, including the month of first independent walking (b = 0.11, p = .03), using words (b = -0.05, p = .02), and using combined phrases (b = 0.20, p < .001). However, the child's current age was the strongest predictor of current communication deficits (b = -0.53, p <. 001). The other core ASD deficit domains (i.e., Repetitive Behavior, Atypical Behavior, Social Reciprocity, and Peer Interaction) also had multiple significant associations with early functional milestones, but variance explained was negligible (R2 = 0.02-0.05). In terms of the second objective, significant predictors of the age of ASD diagnosis (in order of average attainment) included: month of first reported smiling (b = - 0.17, p = .007), walking (b = 0.24, p = .002), use of combined words (b = -0.10, p = .02), combined phrases (b = -0.40, p < .001), bladder-trained (b = -0.07, p = .03), and bowel-trained (b = -0.17, p < .001). Conclusion: This study represents one of the first attempts at examining relationships among the acquisition of early functional milestones and outcomes in children with ASD. The current study may provide critical information related to the screening, diagnosis and intervention prescription for young children with ASD.