The WeeFIM instrument: its utility in detecting change in children with developmental disabilities.

OBJECTIVE To examine the utility of the WeeFIM instrument ("WeeFIM") in detecting changes in the functional status of children with disability. DESIGN Prospective longitudinal design with correlation and responsiveness analysis. SETTING Three facilities providing services to children with developmental disabilities in western New York State. PARTICIPANTS Two hundred five children (72 girls, 133 boys) with identified medical disabilities receiving special services were administered the WeeFIM. Subjects ranged in age from 11 to 87 months and came from diverse socioeconomic and ethnic backgrounds. Scores for 174 children were available for 3 administrations performed over a 1-year period. MAIN OUTCOME MEASURES The responsiveness of the WeeFIM instrument was examined using 5 statistical procedures: Reliability Change Index, Proportional Change Index, effect size, standardized response means, and paired t tests. RESULTS All 5 indexes of responsiveness indicated statistically significant (p < .05) or reliable changes over time. The transfer subscale of the WeeFIM showed a skewed distribution that affected the results for some responsiveness indexes. The advantage, limitations, and assumptions of the responsiveness indexes are described and graphic examples of change over time are presented to validate the responsiveness of the WeeFIM instrument. CONCLUSION The WeeFIM instrument showed the ability to document change in functional abilities over a 1-year period in children with chronic disabilities.