Vocabulary and Syntax Reception in Children with Down Syndrome

Introduction: Intellectual disability and specific cognition in down syndrome (DS) affect language development and processing. We assessed vocabulary and syntax reception among children with DS with typically developed (TD) Persian-speaking Iranian children. We also investigated the association between vocabulary and syntax reception in children with DS. Materials and Methods: Using the Stanford–Binet intelligence scales test, 18 TD children (4-6 years old) and 18 DS children were matched based on non-verbal mental age. Vocabulary reception was assessed using the receptive picture vocabulary test (RPVT) and syntax reception by the Persian syntax comprehension test. Results: Mean total vocabulary reception was lower in children with DS (P<0.001). Syntax reception was also impaired in children with DS compared to the normal values of the test. Among children with DS, vocabulary reception was positively correlated with syntax reception. Every unit increase in total vocabulary reception score was associated with 0.08 (95% confidence interval, CI: 0.04-0.12) improvement in syntax score in children with DS. Conclusion: Vocabulary and syntax reception in DS children, especially complex syntax structures, was impaired. The observed association between vocabulary and syntax reception shows that vocabulary reception improvement might result in progressing syntax reception in children with DS.