Effects of Autism Spectrum Disorder on Discourse: A systematic review

Language deficits in individuals with autism spectrum disorder (ASD) are manifested in discourse, yet a systematic characterization of these deficits is lacking. To determine deficits in discourse macro-structure and micro-structure in individuals with ASD, we conducted a systematic review of recent studies in Covidence following PRISMA guidelines. This review showed language deficits on both narrative microstructure and macrostructure. The evidence indicates that individuals with ASD produce narratives that are shorter, lexically less diverse, and syntactically less complex than those of neurotypical peers. Morphosyntax is preserved particularly in individuals without comorbid language impairments, though morphosyntactic deficits can emerge under high discourse demands. At the macrostructural level, individuals with ASD include fewer complete story grammar elements, show weaker causal/temporal linking, use sparser mental-state vocabulary, and display greater referential ambiguity. The reviewed evidence suggests that narrative difficulties are primarily associated with deficits in discourse planning and socio-cognitive processing, with structural linguistic forms though being relatively more preserved.