Younger siblings of children with autism: Cognitive, language, and social skills

Abstract

Autism has a known genetic linkage shown by increased prevalence of the syndrome in probands. Research has shows that those who do not necessarily fit the clinical diagnosis of autism may display sub-threshold traits, referred to as the broader phenotype of autism. This study looks at younger siblings of children with autism two times over the course of 1.5 years, with entry in the study at 12-23 months. This group is compared to a control group of siblings of typically developing children. 68 children participated in this study (42 male, 27 female) in two groups Sibs-ASD (n=41) and Sibs-TD (n=28). Groups are compared in language, cognitive, social performance and early predictive factors of later diagnosis. Results show that the Sibs-ASD show deficits at Time 1 in cognitive skill and social development, and have worse diagnostic outcomes than Sibs-TD. Within the sibs-ASD group females scored higher than males in the areas of language and cognitive ability. Early predictors of eventual autism spectrum diagnosis were found in lower performance on directing and requesting behaviors, expressive language and social skills.