The Reliability of Postural Balance Measures in Single and DualTasking in Healthy elders

The present study aimsed to examine the reliability of forceplate parameters under both single and dual task conditions and in different levels of postural difficulty. The healthy elderly + 65, were assessed with aone-week interval, with a random combination of three levels of postural difficulty (i.e., standing on a rigid surface with eyes open, standing on a rigid surface with eyes closed and standing on a foam with eyesclosed) and two cognitive conditions (standing with/without performing the cognitive task of backward counting). The signals of center ofpressure (COP) were recorded and the faceplate parameters were calculated. Intraclass correlation coefficient, standard error of measurement and coefficient of variation for all variables and conditions were alsocalculated. During the single task, the area of COP sway, standard deviation (SD) of amplitude in both directions, and SD of velocity in mediolateral direction showed high to very high reliability in all levels of postural difficulty. During the dual task, the total mean velocity and SD of velocity in both directions showed high to very high reliability in alllevels of postural difficulty. Generally, the protocol used to assess balance in the present study, in both dual and single task conditions, showed a suitablerelative and absolute reliability levels in the elderly.