Short versions of the telephone motor functional independence measure for use with persons with spinal cord injury

Objective: To determine if the motor ability of persons with spinal cord injury (SCI) can be reliably estimated using a subset of the 13 Functional Independence Measure (FIM) items. Study Design: FIM item subsets of 5, 6, or 7 items were selected using one of five strategies: random, coefficient alpha maximization, spread across the range of item difficulties, optimization by neurologic category, and individual optimization. Motor ability estimated by these 15 subsets was compared to the 13-item estimate, using intraclass correlation coefficient (ICC), Rasch calibration person reliability estimate, and other indices of reliability. Subjects: Subjects were 4,128 persons with SCI, 1 to 25 years postinjury, interviewed for annual research follow-up using the FIM. Results: All subsets had high ICC reliability (>.90). Subsets of 7 items performed generally better than those of 6 or 5 items. The best performance was provided by individual optimization subsets. The ICC for the 7-item set thus selected was .99. Conclusion: In annual follow-up, the number of FIM motor items can be reduced almost 50% while maintaining reliable estimates of subjects' motor ability. This approach may also be useful for other applications of interviewing to obtain FIM data, eg, for program evaluation.