THE RELIABILITY AND VALIDITY OF THE BALANCE MAT

Abstract

Reliable and accurate postural sway assessment tools are important for monitoring the postural stability of individuals so that interventions can be evaluated, and balance ability is better assessed. The Balance Mat (PSI, ACT, Australia) is a new postural sway assessment device that is relatively cheap and highly portable, but it is yet to be scientifically validated and its reliability tested. Therefore, the aims of this project were to assess the test-retest reliability and validity of the Balance Mat (BM). Seventeen participants (age range 18 – 67) were recruited, and they performed nine balance tests. The reference method for obtaining balance measurements was the AMTI AccuSway-Optimized force platform (Advanced Mechanical Technology, Inc., MA, USA), which was placed below the BM so that force plate and BM data were collected simultaneously. Each participant performed two trials for each test, which were 20 seconds in duration each. From the BM software, the sway variance, mean sway distance, sway range, sway velocity, and sway path were obtained for each trial. From the force platform, the following centre of pressure (COP) measurements were obtained: standard deviation of the radial displacement of the COP; mean radial displacement of the COP; 95% confidence ellipse area; average velocity of the COP; and COP path length. Spearman’s rank-order correlation coefficient was used to test the validity and reliability of the BM. For the comparison between BM and force plate data, correlation coefficients ranged from 0.63 to 0.79 (p<0.001). For the test-retest reliability analyses, correlation coefficients ranged from 0.77 to 0.85 (p<0.001) among the nine tests. The strong to very strong positive correlations suggest that the BM is a valid and reliable tool for assessing postural sway.