Differential Diagnosis of Autism Spectrum Disorder Versus Language Disorder in Children Ages 2 to 5 Years: Contributions of Parent-Reported Development and Behavior.

Early diagnosis of autism spectrum disorder (ASD) has focused on differentiating children with ASD from neurotypical children. However, many children presenting with concern for ASD are ultimately diagnosed with language disorder (LD). This study aimed to identify differences in parent-rated development and behavior among children ages 2 to 5 years presenting with concern for ASD who were diagnosed with either ASD or LD. Children with ASD were rated as more socially withdrawn and more delayed in social development and self-help skills than those with LD. Parent-rated developmental delays were positively correlated with scores on an autism screening measure and with social withdrawal and pervasive developmental problems among children with ASD. Among those with LD, parent-rated social and self-help development were positively correlated with social withdrawal and attention problems. Thus, parent ratings of social withdrawal and development of social and self-help skills may facilitate differential diagnosis of ASD and LD in children ages 2 to 5 years.