Clinical scales of cerebellar Ataxias

Abstract

The development, evaluation, and validation of new clinical scales for the assessment of disease severity and progression in cerebellar disease have gained increasing impact during the last years. Currently, there are four different scales that are most frequently applied: The International Cooperative Ataxia Rating Scale (ICARS), the Brief Ataxia Rating Scale (BARS), the Friedreich Ataxia Rating Scale (FARS), and the Scale for the Assessment and Rating of Ataxia (SARA). All scales have been validated and compared with regard to their testing properties. It has been shown that each scale has its strengths and weaknesses. It is therefore important to carefully select the clinical scale when preparing a clinical or therapeutic study. It is also important to note that the quality of a rating scale is not only defined by its interrater reliability and construct validity but also by its user friendliness. A scale’s compactness guarantees attractiveness to the clinician, reduces expenditure of time and money, and will thereby alleviate further clinical trials. Large, elaborated scales are certainly useful for thorough documentation of specific features of certain phenotypes, but this gain of information is not always essential for the purpose of a study. It is therefore no surprise that short and manageable scales like SARA are often preferred to more elaborated scales in observational and therapeutic studies.