Reliability analysis of posturography using a newly developed automatic balance calibration system

The purpose of this study was to examine the reliability of posturography using a newly developed automatic balance calibration system (I Balance S (CyberMedic Co., Korea)). Twenty-three patients who volunteered participated in this study. Mean center of gravity (COG) sway velocity, total distance, maximum velocity (MV), average movement degree (AMD), maximum excursion (ME) and directional control (DC) were measured by I Balance S. Overall stability index and overall directional control score were measured by Biodex Balance System (Biodex Medical Systems Inc., New York, USA). For the accurate measurement, the COG was automatically calibrated to zero before each measurement by I Balance S. Each subject was tested twice by examiner A and once by examiner B. The intraclass correlation coefficients (ICC) were calculated to assess the inter-rater and intra-rater reliability. Inter-rater reliabilities were higher with the I Balance S (ICC, 0.80-0.91) than with the Biodex Balance System (ICC, 0.71-0.82). Intra-rater reliabilities were similar between the I Balance S (ICC, 0.88-0.94) and the Biodex Balance System SD (ICC, 0.90-0.91). I Balance S using an automatic balance calibration system is a reliable posturography method for performing balance assessments.