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.

• Keywords
• Cerebellum, Cognition, Friedreich ataxia, Spatial navigation, Spatial perspective taking, Spinocerebellar ataxia,
• MeSH
• Adult MeSH
• Friedreich Ataxia * physiopathology   psychology   MeSH
• Cognition MeSH
• Cognitive Dysfunction physiopathology   MeSH
• Middle Aged MeSH
• Humans MeSH
• Cerebellum physiopathology   MeSH
• Neuropsychological Tests MeSH
• Spatial Navigation * physiology   MeSH
• Spinocerebellar Ataxias * physiopathology   psychology   MeSH
• Case-Control Studies MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

BACKGROUND: Cognitive deficits are common in early multiple sclerosis (MS), however, spatial navigation changes and their associations with brain pathology remain poorly understood. OBJECTIVE: To characterize the profile of spatial navigation changes in two main navigational strategies, egocentric (self-centred) and allocentric (world-centred), and their associations with demyelinating and neurodegenerative changes in early MS. METHODS: Participants with early MS after the first clinical event (n = 51) and age-, gender- and education-matched controls (n = 42) underwent spatial navigation testing in a real-space human analogue of the Morris water maze task, comprehensive neuropsychological assessment, and MRI brain scan with voxel-based morphometry and volumetric analyses. RESULTS: The early MS group had lower performance in the egocentric (p = 0.010), allocentric (p = 0.004) and allocentric-delayed (p = 0.038) navigation tasks controlling for age, gender and education. Based on the applied criteria, lower spatial navigation performance was present in 26-29 and 33-41% of the participants with early MS in the egocentric and the allocentric task, respectively. Larger lesion load volume in cortical, subcortical and cerebellar regions (ß ≥ 0.29; p ≤ 0.032) unlike brain atrophy was associated with less accurate allocentric navigation performance. CONCLUSION: Lower spatial navigation performance is present in up to 41% of the participants with early MS. Demyelinating lesions in early MS may disrupt neural network forming the basis of allocentric navigation.

• Keywords
• Allocentric, Cognition, Egocentric, Lesion load, MRI, Neuropsychology, Volumetry, Voxel-based morphometry,
• MeSH
• Cognition MeSH
• Cognitive Dysfunction * MeSH
• Humans MeSH
• Neuropsychological Tests MeSH
• Spatial Navigation * MeSH
• Multiple Sclerosis * diagnostic imaging   MeSH
• Space Perception MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH