Development and Validation of an Objective Balance Error Scoring System

Abstract

Limited access to sophisticated technology and the unreliability of simple tools prevent accurate and reliable human standing balance assessments outside research laboratory settings. The goal of this study was to develop and validate a simple objective balance assessment tool that provides an accurate, reliable, and affordable alternative to currently available laboratory and clinical methods. Thirty healthy subjects were filmed performing the Balance Error Scoring System (BESS) while wearing inertial measurement units (IMU) measuring linear accelerations and angular velocities from seven locations of the body: forehead, sternum, waist, right and left wrist, and right and left shin. Each video was scored by four experienced BESS raters, whose mean scores were used to develop an algorithm computing objective BESS (oBESS) scores solely from IMU data. Interrater reliability and accuracy of oBESS scores were assessed using intraclass correlations (ICC). Raters displayed low variability in scoring (ICC3,1 = 0.91). The oBESS was able to produce scores with accurate fit to raters (ICC3,1 = 0.92) and predicted individual BESS scores (ICC3,1 = 0.90) using data from one IMU placed at the forehead. oBESS was unable to produce accurate scores (ICC3,1 = 0.68) when using IMU data from the subset of conditions (firm surface only) used in popular concussion identification protocols. The oBESS can reliably predict total BESS scores in healthy subjects. Pending further validation, oBESS could represent a valid tool to assess balance by offering an objective and reliable alternative to the current scoring methods of the BESS.