False Beliefs, True Deficits: Investigating Social Cognition in Friedreich Ataxia.

Friedreich ataxia (FA) is a cerebellar neurodegenerative disease primarily known for its motor symptoms, but emerging evidence suggests it also affects higher-order cognitive functions, including Theory of Mind (ToM). This study aimed to assess ToM in individuals with FA using a Picture Sequencing Task (PST) that distinguishes between mechanical, social script, true belief, and false belief scenarios, with a focus on the latter as key marker of mentalizing in cerebellar diseases. Twenty-three FA patients and age- and sex-matched healthy controls completed the PST. Accuracy and normalized reaction times were compared between groups. Correlations between task performance and clinical severity (SARA score) were analyzed within the FA group. P values were adjusted for false discovery rates (p-FDR) using the Benjamini Hochberg method. FA patients showed significantly lower accuracy in the false belief condition (p-FDR = 0.03) and a reduced global accuracy score (p-FDR = 0.03), while other conditions showed no group differences. Accuracy in false belief trials negatively correlated with disease severity (ρ = − 0.482, p-FDR = 0.04). Normalized reaction times did not differ between groups, suggesting preserved processing speed when accounting for motor slowness. Our results reveal a selective impairment in false belief reasoning in FA, consistent with ToM deficits observed in other cerebellar and neurodevelopmental disorders. Not applicable.