Reliability and Validity of Outcome Measures for Upper Limb Amputation

Abstract

Objective: Studies of outcome measures for adults with upper limb amputation are lacking. Our purpose was to examine the measurement properties of the Modified Box and Block Test of Manual Dexterity (BB), the Jebsen-Taylor Test of Hand Function (JTHF), the Upper Extremity Functional Scale (UEFS), the satisfaction scale from the Trinity Amputation and Prosthetics Experience Scale measure (TAPES), and the Patient-Specific Function Scale (PSFS). Specifically we aimed to 1) estimate test-retest reliability, 2) calculate minimum detectable change (MDC), and 3) examine known group validity. Methods: Subjects were 73 adults with upper limb amputation from four study sites. We estimated test-retest reliability using intraclass correlation coefficient (ICC) (3,1), calculated standard error of the measurement, and MDC; assessed scale score distributions; and compared scores by level of amputation using analyses of variance. Results: The ICCs were 0.91 for BB, 0.68 to 0.92 for the JTHF subtests, 0.80 for the UEFS summary, 0.65 for UEFS use, and 0.86 for the TAPES. The MDC was 6.5 items for BB, 0.09 to 0.18 items per second for the JTHF subtests, 12 points for the UEFS summary, 0.39 for UEFS use, and 0.79 for TAPES. Floor effects were observed for the JTHF page turning, small items, and feeding subtests. Subjects with more distal amputation had better dexterity (p < 0.001), better self-reported function on the PSFS (p = 0.01), and greater prosthetic satisfaction (p < 0.05) as compared with persons with higher levels of amputation. Scores on the UEFS did not vary by amputation level. Discussion and Conclusion: The BB, JTHF, and TAPES are reliable and valid for use with adults with upper limb amputation. Further research is needed to examine the test-retest reliability of the PSFS. The UEFS was reliable, but summary scores do not take prosthetic usage into account. Further validation work is needed for this measure. Findings can be used to assist clinicians and researchers in choosing appropriate measures and in interpreting changes in scores with repeat administration.