The aim of this study was to investigate sensorimotor functions that require cerebellar processing, and visuospatial perception and visuospatial abilities in adult patients with attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD).

We included patients with unmedicated ADHD (n = 52), medicated ADHD (n = 39), ASD (n = 33), the combination of unmedicated ADHD and ASD (n = 31) and controls (n = 78). A multimodal set of neurocognitive tests and motor tasks were administrated to evaluate cognitive and motor skills.

All patient groups exhibited significantly worse performances than controls in sensorimotor functions, visuospatial perception, and visuospatial abilities. We observed significant associations between sensorimotor functions and visuospatial perception and visuospatial abilities. We conducted a regression analysis to evaluate the impact of potential confounders on neurocognitive outcomes. The results indicated that age, level of education, and insomnia, but not anxiety or depression, affected the performance on some tests.

Our results reveal deficits in sensorimotor functions, visuospatial perception, and visuospatial abilities in patients with neuropsychiatric disorders. Clear deficits emerged, despite the majority of patients showing a mild degree of severity index of ADHD/ASD across all groups (61–84%). The results are consistent with the idea that these disorders are linked to cerebellar deficits. Our results suggest that these objective tests have the potential to enhance clinical evaluations.