Objective home-based gait assessment in spinocerebellar ataxia

We investigated the utility of home-based gait monitor assessment in patients with spinocerebellar ataxia (SCA). Nineteen patients with different forms of SCA were examined using a step activity monitor (SAM), clinical scales and common tests of functional motor performance including the scale for assessment and rating of ataxia (SARA), disease staging, a timed 25 foot walk test and a 9 hole peg-board test. The patient wore the SAM bracelet on his/her ankle for seven 24 hour periods at home. The objective monitor measurements were highly associated with disease duration and with the functional stage of disease (P < 0.01). Monitor measurements were significantly correlated to SARA scores with the exception of the percent of steps expended in moderate and high speeds of activity. Fewer monitor measures had significant correlations with walk and peg board scores. The objective SAM outputs also possessed high internal consistency, high intraclass correlation coefficients and could be fitted to a single factor by factor analysis. We conclude that the SAM is a simple and cost effective method for obtaining data on gait parameters over extended periods in patients with SCA. The SAM has validity and reliability and can generate unbiased, continuous data that takes into account daily variations in physical performance.