Spatial perspective taking is impaired in spinocerebellar ataxias and Friedreich ataxia

Spinocerebellar ataxias (SCA) are rare neurodegenerative diseases affecting the cerebellum and its connections, leading to progressive motor disability and cognitive impairment as part of the cerebellar cognitive affective syndrome. Spatial navigation, cognitive function important for everyday movement, relies on spatial perspective taking-the ability to imagine the environment from different viewpoints. While animal and neuroimaging studies suggest a crucial role of the cerebellum in spatial navigation, research on patients with cerebellar disorders is lacking. This study aimed to investigate perspective taking in patients with SCA and Friedreich ataxia (FRDA) using two tests. The Perspective-Taking/Spatial Orientation Test (PTSOT) was administered to 30 SCA patients, 30 FRDA patients, and 34 healthy controls (HC). In addition, SCA and HC completed the Directional-approach Task and a comprehensive neuropsychological assessment. SCA patients performed significantly worse than HC on both perspective taking tests. FRDA patients performed better than SCA and differed from HC only in a subset of PTSOT measures. Perspective taking performance in SCA was associated with global cognition and multiple cognitive domains but not with cerebellar motor impairment. These findings are of potential clinical relevance, as spatial navigation deficits are known to negatively affect the mobility and independence of the affected individuals. Our findings expand the understanding of cognitive impairments in cerebellar diseases, adding spatial navigation to the spectrum of the cerebellar cognitive affective syndrome.