Measuring change in disability after inpatient rehabilitation: comparison of the responsiveness of the Barthel Index and the Functional Independence Measure

BACKGROUND: The importance of evaluating disability outcome measures is well recognised. The Functional Independence Measure (FIM) was developed to be a more comprehensive and "sensitive" measure of disability than the Barthel Index (BI). Although the FIM is widely used and has been shown to be reliable and valid, there is limited information about its responsiveness, particularly in comparison with the BI. This study compares the appropriateness and responsiveness of these two disability measures in patients with multiple sclerosis and stroke. METHODS: Patients with multiple sclerosis (n=201) and poststroke (n=82) patients undergoing inpatient neurorehabilitation were studied. Admission and discharge scores were generated for the BI and the three scales of the FIM (total, motor, and cognitive). Appropriateness of the measures to the study samples was determined by examining score distributions, floor and ceiling effects. Responsiveness was determined using an effect size calculation. RESULTS: The BI, FIM total, and FIM motor scales show good variability and have small floor and ceiling effects in the study samples. The FIM cognitive scale showed a notable ceiling effect in patients with multiple sclerosis. Comparable effect sizes were found for the BI, and two FIM scales (total and motor) in both patients with multiple sclerosis and stroke patients. CONCLUSION: All measures were appropriate to the study sample. The FIM cognitive scale, however, has limited usefulness as an outcome measure in progressive multiple sclerosis. The BI, FIM total, and FIM motor scales show similar responsiveness, suggesting that both the FIM total and FIM motor scales have no advantage over the BI in evaluating change.