Quantitative evaluation of stance balance performance in the clinic using a novel measurement device

This study was undertaken to test the clinical applicability of a novel device for measurement of stance balance performance. Samples were taken from hemiparetic patients (n = 27, age range 60-80) and of three groups of healthy subjects (24 subjects at ages 64-81, 13 at ages 27-50 and 24 aging 20-24 years). Stance was evaluated in six different positions incorporating two perturbing effects: visual deprivation and movements--linear and angular--of the base of support. Three variables were measured: sway and the values of the X and Y coordinates of the Center of Pressure. Concurrent validity of the system was assessed by comparing results with data of other works that tested comparable variables in similar populations and with already well established instrumentation. Repeatability of measurements was checked by performing all tests twice and comparing their results, as well as by calculating test retest reliability. The findings pointed to significant effects of vision and of movement of the base of support on sway, and to a significant difference between sway of hemiparetic patients and healthy subjects. The location of the COP in both the X and Y coordinates was not substantially influenced by the above effects. The agreement of the findings with existent knowledge indicates that the system is credible for measurement of body sway and of the location of the COP in various stance positions.