Mental rotation and language in autism spectrum disorder.

Though visuospatial skills are often considered a relative strength in autism spectrum disorder (ASD), unexplained difficulties relative to neurotypical (NT) peers have also been observed. Dissociations between spatial cognition and language skills in ASD may explain these difficulties given that these systems are linked in NT individuals. The current study examined performance on a mental rotation task that systematically varied stimulus features and the degree to which performance was associated with language in ASD relative to NT peers. Participants were children and young adults with ASD and 25 pairwise age- and IQ-matched NT peers (p's>0.53). The mental rotation task involved four conditions: two-dimensional (2D) abstract figures, three-dimensional (3D) abstract figures, 2D common objects, and 3D common objects. Structural language was measured using the grammar subscale from the Test of Language Development: Intermediate adapted for Norwegian. Mixed-effects model results indicated that autistic individuals were less accurate and had slower reaction time across mental rotation task conditions than NT peers. Language was associated with mental rotation accuracy for both groups across conditions, but with reaction time only for the NT group. The current study demonstrated selective associations between language and performance on a classic spatial cognition task in autistic individuals. Namely, there was a dissociation between language and in-the-moment efficiency in the ASD group, and this dissociation may reflect a broader dissociation between visuospatial and language systems.