Reliability, validity, and responsiveness of the locomotor capabilities index in adults with lower-limb amputation undergoing prosthetic training

Abstract

Franchignoni F, Orlandini D, Ferriero G, Moscato TA. Reliability, validity, and responsiveness of the Locomotor Capabilities Index in adults with lower-limb amputation undergoing prosthetic training. Arch Phys Med Rehabil 2004;85:743-8. Objective To assess the reliability, validity, and responsiveness of both the standard and revised Locomotor Capabilities Index (LCI) in people with lower-limb amputation who undergo prosthetic training. Design Reliability and validity study. Setting Two freestanding rehabilitation centers. Participants Fifty inpatients with a recent unilateral lower-limb amputation. Interventions Not applicable. Main outcome measures The standard LCI and a new version with a 5-level ordinal scale (LCI-5) were tested for internal consistency, test-retest reliability, ceiling effect, and effect size. The construct validity of both versions was analyzed by correlation with the Rivermead Mobility Index, a timed walking test, and the FIM instrument. Results The Cronbach α of both LCI versions was .95. The item-to-total correlations (Spearman ρ) ranged from .50 to .87 ( P<.0001 for all). The percent agreement and κ values for the item scores ranged, respectively, from 78.4% to 100% and .58 to 1.00 in the LCI, and from 75.7% to 97.3% and .54 to .96 in the LCI-5. The intraclass correlation coefficient (model 2,1) for the total scores was .98 for both versions; the Bland-Altman plot revealed no systematic trend for either version. Both the LCI and LCI-5 correlated with all criterion measures (ρ range, .61–.76), with the LCI-5 showing a larger effect size during the rehabilitation period and a lower ceiling effect. Patients with transtibial amputation were more independent in performing activities than were those with transfemoral amputation; their locomotor capability negatively correlated with age. Conclusions Both the LCI and LCI-5 captured the global locomotor ability of people with lower-limb amputation during prosthetic training. The new LCI-5 presents similar and sometimes better psychometric properties than the standard LCI.