| Abstract: | Comparison of the University of California (Los Angeles) shoulder scale and the simple shulder test with shoulder pain and disability index: Single‐administration reliability and validity. (Texas Woman's University, Houston, TX) Phys Ther. 2000;80:759–768. This study compared 2 shoulder measures—the University of California‐Los Angeles (UCLA) Shoulder Scale and the Simple Shoulder Test (SST)—with the Shoulder Pain and Disability Index (SPADI). One hundred ninety‐two patients with shoulder disorders were recruited from one physician's office to complete the self‐report sections of the 3 scales. Cronbach alpha values and standard errors of measurements (SEM) were calculated for each of the multi‐item subscales. Validity was examined through calculation of correlation coefficients among the 3 scales. Factor analysis was completed to assess the underlying constructs of the SPADI and SST. Cronbach alpha values ranged from 0.85 to 0.95. The SEM values for the multi‐item scales ranged from 4.75 to 11.65. Evidence for validity to reflect function was indicated by the correlation between the SST and the SPADI disability subscale. The factor analysis of the SPADI revealed loading on 1 factor, whereas the SST loaded on 2 factors. Conclude that all scales demonstrated good internal consistency, suggesting that all items for each scale measure the same constract. However, SEMS for all scales were high. Factor loading was consistent, suggesting that patients may not distinguish between pain and function. Comment by Philip S. Sizer Jr., MED, PT. Clinical practitioners are leaning toward evaluating functional status versus a pure‐impairment‐based approach to appraising shoulder limitations. Several scales have been developed for the evaluation of shoulder function, including the University of California Los Angeles Shoulder Scale (UCLA), the Simple Shoulder Test (SST), and the Shoulder Pain and Disability Index (SPADI). Investigations demonstrating the psychometric properties of these scales are limited in number. These investigators attempted to assess those properties, including internal consistency, reliability, and validity for all 3 scales. The analyses demonstrated internal consistency and construct homogeneity for the SPADI. However, all 3 scales demonstrated rather large standard errors of measure, which questions the reliability of the scales for measurement of an individual's progress. Regarding construct validity, the SPADI does not appear to distinguish between pain and dysfunction, disqualifying its use as a gold standard for comparison with other scales. While the SST purports to measure a single construct, the data suggests that it appears to measure 2 different constructs namely function and comfort. Additionally, the analyses appear to demonstrate that, while the scales may attempt to measure the same constructs, they apparently do not. Finally, the authors suggest that the precision of the UCLA scale is inferior to the other 2 scales and insufficient for following the progress of individual patients in the clinical setting. |
