Extrapyramidal Motor Signs in Degenerative Ataxias

Abstract
CEREBELLAR ATAXIAS are a genetically, clinically, and pathologically heterogeneous group of neurodegenerative disorders in which extrapyramidal systems are involved in a highly variable manner. Extrapyramidal motor signs (EPS) vary even within a genetically well-defined subtype, such as Machado-Joseph disease.1,2 On the other hand, EPS are constitutive for the clinical diagnosis of disease entities such as multiple system atrophy (MSA).3 Little is known about the diagnostic value of EPS in particular forms of ataxia, however, and data about the frequency of EPS in genetically defined subtypes of ataxia are scant.