Complex syntax in autism spectrum disorders: a study of relative clauses

Area of Science:

• Linguistics
• Neurodevelopmental Disorders
• Cognitive Science

Background:

• Existing research on syntax in autism spectrum disorder (ASD) presents conflicting findings regarding grammar abilities and their relationship to cognitive skills.
• A clearer understanding of syntactic processing in ASD and its dissociation from nonverbal abilities is needed.

Purpose of the Study:

• To assess syntax in ASD by examining subject and object relative clause comprehension in adolescents and adults.
• To investigate these abilities in individuals with ASD within the normal performance IQ range, with or without a history of language delay.

Main Methods:

• Twenty-eight adolescents and adults with ASD and 28 age-matched controls participated.
• Participants completed a task requiring them to identify characters based on relative clauses of varying syntactic complexity.

Main Results:

• Participants with ASD performed significantly worse than controls on object relative clause comprehension, irrespective of language delay history.
• ASD individuals with a history of language delay showed greater difficulty with subject relatives compared to those without a history of language delay.
• Higher performance IQ positively correlated with task success in the ASD group.

Conclusions:

• Subtle grammatical deficits persist in adults with ASD within the normal IQ range, potentially evading detection by standard assessments.
• Even without a childhood language delay history, some individuals with ASD may exhibit undetected syntactic challenges.
• Linguistic abilities differ between ASD subgroups with and without a history of language delay, particularly in subject relative clause processing.