Dis/Associations Between Language and In-the-Moment Mental Rotation Effort in Autism.

In-the-moment dissociations between language and visuospatial systems in autism spectrum disorder (ASD) may explain notable heterogeneity observed in both language and visuospatial skills. The current study used pupillometry, a physiological measure of in-the-moment cognitive effort, during a mental rotation task to examine associations between structural language and visuospatial cognition. Participants were 25 children and young adults with ASD and 25 age- and IQ-matched neurotypical (NT) peers. The mental rotation task involved four conditions: two- and three-dimensional figures, and two- and three-dimensional objects. We measured structural language using the grammar subscale from the Test of Language Development: Intermediate. Growth-curve mixed-effects model results indicated no overall group differences in average pupil dilation or the time course of cognitive effort. Group differences were evident in the association between grammar skills and latency of cognitive effort for stimuli in the objects, 3D, and, more narrowly, 3D objects conditions. Autistic individuals with relatively better grammar skills deployed cognitive effort less efficiently, whereas, NT individuals with relatively better grammar skills deployed cognitive effort more efficiently. These findings suggest that language and visuospatial systems are more dissociated in autistic individuals than in NT peers. This work underscores the importance of examining the time course of how language and cognition interact in ASD.