Comparison of upper-extremity balance tasks and force platform testing in persons with hemiparesis

Background and Purpose. The purpose of this study was to investigate the relationship between clinically accessible functional balance tools and sophisticated force platform measures in a standing position. Subjects. Twenty persons who had hemiparesis secondary to a stroke and were ambulatory (mean age = 57.9 years, SD = 13.6, range = 35-79) were evaluated during a single testing-session. Methods. Performances on self-generated upper-extremity balance tasks using the nonparetic side (Functional Reach Test [FRT], arm raise and arm reach tasks) were compared with responses to external perturbations on the Balance System(TM) (postural sway, symmetry of weight distribution). Results. No relationship was found between the upper-extremity balance tests and the force platform measures of postural sway. After suppressing the effect of age by means of partial correlation coefficients, the FRT was correlated with measures of postural symmetry in parallel stance on the Balance System(TM) (r = .66-.78). The FRT was only moderately correlated with the arm raise and arm reach tasks (r = .43 and .44). Conclusion and Discussion. Postural sway in response to force platform perturbations may have little relation to the postural control necessary for self-generated upper-extremity balance tasks. In contrast, the FRT and the force platform measures of postural symmetry appear to be evaluating comparable standing-balance abilities in persons with hemiparesis. The modest relationship between the FRT and the arm raise and arm reach tasks limits the finding's clinical relevance.