Language outcome in individuals with autism spectrum disorder (ASD) is predicted by early developmental milestones and cognitive abilities. The development and acquisition of expressive language (particularly the onset of first phrases) is a relevant clinical milestone by school age, since its early presentation is associated to better long-term life outcomes and to lower core clinical severity of ASD. Focusing on predictors of language in ASD children, a number of outstanding questions remain to be answered, namely, whether there are differences in the early key neurodevelopmental abilities and whether those differences in a specific period of time might predict verbal development and acquisition of expressive language. We aim to understand how the neurodevelopmental profile of ASD children evolves from the preschool to the school age and if and which subarea can better predict acquisition of expressive language. Children with ASD (N = 205) were evaluated with a structured assessment of neurodevelopment in two different age periods: 1) preschool period (mean age four years) and 2) reassessment in the school period (mean age seven years). Our findings demonstrate that in nonverbal preschool children with ASD normal or near normal Performance Developmental Quotient (superior to 73.5) evaluated at preschool age is a good predictor of later language development in ASD, which has important implications for intervention programs targeting this population and family information.
Keywords: Autism spectrum disorder; Early neurodevelopmental predictor; Griffiths mental development scales; Neurodevelopmental milestones; Verbal ability.