The international cooperative ataxia rating scale in Machado-Joseph disease. Comparison with the unified multiple system atrophy rating scale

Abstract

Our purpose was to evaluate and compare the international cooperative ataxia rating scale (ICARS) and the unified multiple system atrophy rating scale (UMSARS) in patients with Machado-Joseph disease (MJD). We assessed 52 consecutive subjects with MJD using each scale. Both scales had adequate internal consistency (alpha > 0.90), except for the oculomotor (OD) subscore (alpha = 0.08). Patients with dystonia had the highest scores in both scales, and symptoms other than ataxia clearly confounded the total ICARS score. There was a very strong correlation between the ICARS and UMSARS-II (motor function), and the correlations between the ICARS and UMSARS-I (r = 0.79) (history) and UMSARS-IV (r = 0.69) (disability) were also statistically significant. We found no significant changes in scores after a mean interval of 7.7 months, although there was after a mean interval of 13.3 months. We conclude that the total ICARS score is a reliable method for longitudinal evaluation of ataxia in MJD, but a disease specific scale should be developed.