Reliability and minimal detectable change of body-weight distribution and body sway between right and left brain-damaged patients at a chronic stage

Abstract

Purpose To assess the reliability and minimal detectable change (MDC) of weight-bearing asymmetry (WBA) and body sway (BS) during “eyes open” (EO) and “eyes closed” (EC) conditions for those with right brain damage (RBD) and left brain damage (LBD) at a chronic stage. Methods Sixteen RBD and 16 LBD patients participated in two sessions within 15 days, composed of two trials of 30 s using a double force platform. Intraclass correlation coefficient (ICC2,1), the standard error of measurement (SEM), and MDC were calculated for WBA and BS (area and velocity of sway). Results Reliability of WBA was excellent (>0.75) except for EC for LBD patients (low SEM was found). The condition of EC was similar to or less reliable than that of EO. The MDC of WBA was 5.4 and 7.3% for LBD and RBD patients, respectively. Velocity of sway should be favored over the area of sway due to better reliability, with an MDC of 9 and 13 mm/s for RBD and LBD patients, respectively. Conclusions Parameters related to WBA and BS were highly reliable, without a difference between RBD and LBD patients, but less so in the condition of EC, and could be used for clinical rehabilitation and/or research. Implications for rehabilitation Weight-bearing asymmetry (WBA) and body sway (BS) are highly reliable posturography parameters. Reliability of WBA/BS is similar among right brain damaged (RBD) and left brain damaged (LBD) patients. A change of 5–7% can be interpreted as significant for WBA for chronic stroke. The minimal detectable change in measures is slightly higher for RBD patients.