MEASURED VS PERCEIVED PHYSICAL FUNCTION

Abstract

Physical function can be assessed by performance tests, such as the Continuous-Scale Physical Functional Performance test (CS-PFP), or by self-administered questionnaires of perceived function, as in the SF-36 Physical Functioning scale (SF36-PF). We questioned whether perceived abilities accurately reflect measured performance in selected tasks. PURPOSE To determine the association between measured and self-perceived function in the elderly. METHODS Community-dwelling women (n=24) and men (n=39), aged 70±7 y (mean±SD), BMI=28±5 kg/m2, completed the CS-PFP and SF-36. The variable PF8 was computed from 8 items in the SF36-PF that are similar to tasks in the CS-PFP. Total CS-PFP scores were correlated with PF8 using Pearson tests, and then adjusted for age. RESULTS CS-PFP (60.3±14.8) and PF8 (86.8±11.9) scores were typical of community-dwelling older adults with minor medical conditions. CS-PFP and PF8 scores were moderately associated before (r=0.60, p < .001) and after (r=0.48, p < .001) adjusting for age. CONCLUSION Older adults perceive their functional performance with moderate accuracy. With only 23–36% of the variance shared by self-reported and measured physical function, preclinical functional loss may not be detected by self-report. Supported by NIH Grant R01 AG18857 and GCRC Grant M01-RR00051.