Motor and cognitive impairments in spinocerebellar ataxia type 7 and its correlations with cortical volumes. (26th September 2018)

• Record Type: Journal Article
• Authors: Chirino, Amanda; Hernandez‐Castillo, Carlos R.; Galvez, Victor; Contreras, Anabel; Diaz, Rosalinda; Beltran‐Parrazal, Luis; Fernandez‐Ruiz, Juan
• Is Part Of: European journal of neuroscience. Volume 48:Number 10(2018)
• Page Start: 3199
• Page End: 3211
• Publication Date: 2018-09-26
• Subjects: autosomal dominant ataxia -- cognitive impairments -- motor impairments -- volumetric magnetic resonance; Nervous system -- Periodicals; 612.8
• DOI: 10.1111/ejn.14148
• Languages: English
• ISSNs: 0953-816X

Abstract

Abstract: Spinocerebellar Ataxia Type 7 (SCA7) is a neurodegenerative disorder caused by cytosine‐adenine‐guanine (CAG) repeat expansion. It is clinically characterized by ataxia and visual loss. To date, little is known about SCA7 cognitive impairments and its relationship with grey matter volume (GMV) changes. The aim of this study was to explore SCA7 patients' performance in specific components of auditory‐verbal neuropsychological tests and to correlate their scores with genetic mutation, severity of ataxia and GMV. We assessed verbal memory and verbal fluency proficiencies in 31 genetically confirmed SCA7 patients, and compared their results with 32 healthy matched volunteers; we also correlated CAG repeats and severity of motor symptoms with performance in the auditory‐verbal tests. SCA7 patients exhibited deficiencies in several components of these cognitive tasks, which were independent of motor impairments and showed no relation to CAG repeats. Based on Resonance Images performed in 27 patients we found association between ataxia severity and GMV in "sensoriomotor" cerebellum, as well as correlations of impaired verbal memory and semantic fluency scores with GMV in association cortices, including the right parahippocampal gyrus. To our knowledge, this is the first report of deficits in the organization of semantic information and in the evocation of verbal material, as well as greater susceptibility to proactive interference in SCA7 patients. These findings bring novel information about specific cognitive abilities in SCA7 patients, particularly verbal memory and fluency, and their relation with GMV variations in circumscribed brain regions, including association cortices known to have functional relationships with the cerebellum. Abstract : Here we showed that SCA7 patients have deficits in the organization of semantic information and evocation of verbal material, as well as susceptibility to proactive interference. These deficits were related to grey matter volume changes in association cortices, including the right parahippocampal gyrus. In contrast, ataxia severity was related to cerebellar grey matter volume changes. These novel findings point to an executive control process disorder in SCA7.