Measurement characteristics of the Functional Independence Measure

Abstract

Clinicians and researchers recognize the need for measures offunctional status that possess linear properties and are reliable and valid. Rasch rating scale analysis provides the means for converting raw scores from functional assessment tools to linear measures for which measurement error can be quantified. The extent to which clinicians perceive patients who are undergoing rehabilitation after stroke as similarto other patient groups was investigated using the Functional Independence Measure (FIM). Earlier work demonstrated that the first 13 items of the FIM represent a measure of motor function and that the last 5 items represent a measu re of cognitive function. The FIM was used for patients with stroke in a manner similar to that for most other impairment groups on the motor items. Patients with stroke were, however, unlike many impairment groups in their ratings on the cognitive items. Tables showing raw score to scaled measure conversions are provided for two sets of impairment groups on the motor items and three sets of impairment groups on the cognitive items. Clinicians can be confident that the measures derived from the FIM are linear across the range of the instrument and are attuned to the uniqueness of patients with stroke and other specific impairments.