07 Examination of Reliability and Validity of Index of Postural Stability for Patients with Neurological Diseases

Abstract

Abstract Purpose The purpose of this study was to examine the reliability and validity of the Index of Postural Stability for patients with neurological disease. Methods The Index of postural stability (IPS) is a logarithmic value of the ratio between the stability limit and the area of centre of pressure (COP) in standing position, and is based on a probabilistic idea. Subjects were 75 patients with neurological disease (mean age; 63±12 years, 47 with Parkinson's disease, 9 with multiple sclerosis, 8 with Parkinsonism and others 11). Balance ability of subjects were assessed using IPS, Berg balance scale (BBS), Timed Up and Go Test(TUG), Functional Reach Test(FR), and gait ability of subjects were assessed using Functional Gait Category(FAC). IPS was assessed twice at intervals of about 30 minutes. Reliability of IPS was examined using Intraclass correlation coefficient (ICC), Bland-Altman plot and minimal detectable change (MDC). Validity of IPS was examined using correlation coefficients with BBS, TUG, FRT, and FAC. Results IPS showed significant and moderate correlation with BBS (r = 0.54), FR (r = 0.36), TUG (r =-0.43). IPS and FAC showed strong correlation (rs= 0.64). ICC of 2 separate measurements was 0.96. From the results of Bland-Altman plot, IPS had no additional error or proportional error (95%CI:-0.048~0.034, r=-0.0088, p=0.94). The MDC of IPS was 0.34. Discussion Since IPS has high reproducibility and does not have additional errors or proportional errors, and is also significantly related to other evaluation indexes of balance ability, it is considered that IPS may be a useful evaluation index of balance ability for patients with neurological diseases.