Article

Discriminant Analysis of the Patient-Specific Functional Scale in Discerning Between Loss of Physical Function Categories in Community-Dwelling Older Adults

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Abstract

Previous research indicates that the Patient-Specific Functional Scale (PSFS) is a reliable and valid measure of loss of physical function in community-dwelling older adults. However, the ability of the PSFS to classify community-dwelling older adults into categories of loss of physical function has not been investigated. The purpose of this study was to investigate the ability of the PSFS to discern between different categories of physical function loss in community-dwelling older adults. Thirty-one community-dwelling older adults (mean age = 81.1 years; SD = 8.3) completed a set of physical function questionnaires: the PSFS, the Lower Extremity Functional Scale (LEFS), and the Activities-specific Balance Confidence (ABC) scale. Study participants also completed the Short Physical Performance Battery (SPPB). Scores on the PSFS, LEFS, ABC scale, and SPPB were divided into loss of physical function categories (mild, moderate, severe, and very severe). Discriminant analysis was used to determine the ability of the PSFS to discern between the different categories of loss of physical function. The canonical correlation between the eigenvalues and classifications for the LEFS, ABC scale, and SPPB was 0.85 (P < .001), 0.72 (P < .001), and 0.40 (P = .18), respectively. The findings of this investigation indicate that the PSFS has predictive ability to classify community-dwelling older adults into categories of loss of physical function, based on LEFS and ABC scale classifications, which could be important for purposes such as evaluation, screening, and measuring clinically important differences in loss of physical function.

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Interpretation of patient scores on functional tests is enhanced by an understanding of test performance in reference groups. The purpose of this study was to expand performance values, by age and gender, on balance tests [the Multi-Directional Reach (MDRT); Berg Balance (BBS); Sharpened Romberg, eyes open (SREO), eyes closed (SREC); Activities-Specific Balance Confidence (ABC)], and a general mobility test [Physical Performance Test, (PPT-7, PPT-9)]. The study also examined relationships between test performance and subject characteristics. Eighty-three community-dwelling adults over 50 participated in the study and completed the 5 functional tests during one test session. Means, standard deviations, and confidence intervals were calculated for each of the tests. Multiple linear regression analysis was used to examine relationships between test scores and age, gender, height, and weight. Test performance is reported by gender,within 10-year age cohorts. Regression analysis showed that age contributed significantly to prediction of performance on all of the tests and gender contributed significantly to prediction of scores on the Berg, SREO, and SREC. Test performance values, in a sample of community-dwelling adults, is provided by age and gender cohorts to provide additional reference data that can be used by clinicians for comparison with client data. The small sample size for subjects over 80 years limits the reference value of data for this age group. In regression analyses, age and gender help predict outcomes on the dependent variables used in the study.
Accessed January 12, 2018.
  • E Mitchell