Comparing Theory of Mind Skills and Language Performance between Children with Developmental Language Disorder, High-Functioning Autism, and Typically Developing Children

Background and purpose: Theory of Mind (TOM) is a cognitive ability to understand the beliefs, emotions, and desires of oneself and others, and its development is associated with proper development of other cognitive skills, including language. This study aimed at investigating the relationship between language and TOM and comparing the grammatical and lexical performances and TOM skills between children with high-functioning autism (HFA) and developmental language disorder (DLD) and typically developing (TD) children. Materials and methods: A cross-sectional study was carried out in 50 children aged 6-11 years old, native speakers of Persian language, with DLD (n= 14) and HFA (n= 11), and in TD (n= 25) children. Assessment of language skills was done by lexical and syntactic indicators obtained from the analysis of narrative speech sample and Persian grammar expression test (PEGT) and TOM skills using Persian mind theory test. Data were analyzed in SPSS V22 using ANOVA, Pearson Correlation, Kruskal-Wallis test, and Spearman correlation. Results: There were no significant differences in most grammatical, lexical, and TOM scores between children with DLD and HFA (P<0.05), but the performances of both groups were found to be significantly lower than TD children (P>0.05). Significant correlation was observed between overall scores and TOM and PEGT scores in all three groups (P< .05). Conclusion: The current study revealed that children with HFA and DLD have weaker TOM skills than TD children which could be due to their language deficits.