Assessment of the upper limb in acute stroke: The validity of hierarchal scoring for the Motor Assessment Scale

Abstract

Stroke is the greatest contributor to disability in Australian adults and much of this disability results from a stroke-affected upper limb. This study aimed to determine the validity of hierarchal scoring for the upper limb subscale of the Motor Assessment Scale (UL-MAS) in acute stroke using Rasch analysis. This study applied Rasch analysis to 40 UL-MAS assessment results across 25 subjects to determine the validity of the hierarchy of the three upper limb subsets: upper arm function (six), hand movements (seven) and advanced hand activities (eight). Rasch analysis examines the relationship between 'item difficulty' and 'person ability' and produces an output which represents the difficulty of each item in relation to each other. As hypothesised, the hierarchy was upheld within subset 6. In subset 7, the hierarchy was not upheld. Results indicated that item 3 was the least difficult, followed by items 1, 4, 2, 5 and 6 in order of increasing difficulty. In subset 8 the hierarchy was not upheld. Results indicated that item 1 was the least difficult, followed by item 6, then 2 and 5 of equal value and then 3 and 4 of equal value. The hierarchal scoring is not supported for subsets 7 and 8 and future research is required to explore the validity of alternate scoring methods. At present, the authors recommend that the UL-MAS should be scored non-hierarchally, meaning that every item within the subsets should be scored regardless of its place within the hierarchy (UL-MAS-NH).