Validity of Lower Extremity Postural Sway for Baseline Concussion Testing

Abstract

Objectives: The Balance Error Scoring System (BESS) and King-Devick (KD) are utilized frequently in the athletic population for baseline testing, despite the BESS lacking sensitivity. Biomechanical testing detects smaller magnitudes of change but has not been validated against clinical tests. The objectives of this study were to examine the distribution of Lower Extremity (LE) sway variables in an athletic population; to examine the relationship between clinical and biomechanical concussion testing measures. Design: Cross sectional. Methods: 96 healthy Division I collegiate athletes were tested for both biomechanical and clinical concussion tests. Single Leg Stance (SLS) was performed blindfolded for 2.20 second trials each LE on a force plate system. Center of pressure data (LE sway) was converted to T-score and averaged across the two trials by side. Baseline BESS and KD scores were obtained from the athletes’ files. Descriptive statistics assessed the data distribution. Spearman’s rho (rho) correlations were used to determine the relationship between clinical and biomechanical test variables. Significance was set to P = 0.05. Results: LE sway and KD was normally distributed; BESS showed a floor effect. LE sway was significantly correlated to BESS test subsections (SLS, foam: rho = -0.30, 95% CI: -0.47, -0.11 and foam total score: rho = -0.30; 95% CI: -0.47, -0.11), BESS total score (rho = -0.31; 95% CI: -0.48, -0.12), and KD average (rho = -0.38; 95% CI: -0.54, -0.19). Conclusions: The lower extremity sway scores demonstrate validity when compared to clinical concussion tests. The distribution of sway scores indicates that this test may be better suited to detecting subtle differences in changes, and overcomes the limitations of the conventional clinical evaluations.