Using compensations to assess physical performance for ambulatory outpatients.

Objective: To construct a physical performance scale for community-dwelling ambulatory outpatients that is linear, includes high functioning tasks, and uses common compensations to assess difficulty levels.

Design: Calibrated subject performances on 19 tasks were rated by an examiner, timed, and had compensations recorded.

Setting: Ambulatory outpatient physical therapy (PT) department of a tertiary care center.

Participants: Convenience sample of 50 community-dwelling patients with difficulties in mobility referred for PT.

Interventions: Not applicable.

Main Outcome Measures: The Community Ambulatory Physical Performance Scale (CAPPS) constructed by using Rasch analysis, the Lower Extremity Functional Scale (LEFS), and the six-minute walk test (6MWT).

Results: The CAPPS showed construct validity after removal of 3 items. Two additional items were removed for improved clinical utility. The person reliability was .89 and item reliability was .98. Subjects' performance on the CAPPS correlated with the 6MWT (r=.79; 95% confidence interval [CI], .65-.87) and with the LEFS (r=.62; 95% CI, .40-.78).

Conclusions: The CAPPS showed good psychometric properties and has utility for assessments of higher-level physical functioning. This standardized approach to performance testing for ambulatory outpatients appears to be a promising method for articulating the compensations persons use to accomplish common tasks. Use of compensatory strategies to assess difficulties in physical performance may assist in delineating interventions directed toward improving task performance.