Evaluating the effectiveness of stroke rehabilitation: Choosing a discriminative measure

Objective: To evaluate the discriminative ability of several measures of physical disability used to determine quality of outcome for poststroke rehabilitation. Design: A comparative study, using Rasch analysis, of the discriminative ability of functional status and mobility measures in rehabilitation patients with stroke. Setting: A 26-bed rehabilitation unit, on site of a tertiary teaching hospital in Melbourne, Australia. Participants: A consecutive sample of 106 patients with acute stroke admitted for rehabilitation. Interventions: Not applicable. Main Outcome Measures: Rasch analysis of the motor subscale of the FIM(TM). instrument, Motor Assessment Scale, Functional Ambulation Classification, gait Velocity, and gait endurance. Results: The more difficult items of the FIM motor scale adequately discriminated among higher functioning patients. The gait velocity measure further distinguished 9% of the sample, who functioned at a higher level than could be indicated by FIM motor subscale. The other measures did not add levels of discrimination to that provided by the FIM motor. Ability estimates provided by Rasch analysis of the FIM motor scale were a more accurate indication of ability than raw scores. Raw scores underestimated change in ability observed at higher levels of ability. Conclusion: Rasch estimates of the FIM motor subscale provide a discriminative measure for evaluating outcomes and change in ability achieved in stroke rehabilitation.