Cleveland Clinic Postural Stability Index Norms for the Balance Error Scoring System

Despite the widespread utilization of the Balance Error Scoring System (BESS) in the evaluation of concussion, it has been criticized for its error-based scoring that is susceptible to floor and ceiling effects and substantial inter-rater variability. A biomechanical outcome, Cleveland Clinic Postural Stability Index (CC-PSI), has been developed as an alternative to subjective BESS scoring. The CC-PSI uses inertial sensor data within a mobile device to provide an objective measure of postural sway during the BESS. This project aimed to determine the effect of age and sex on the CC-PSI and report normative values for healthy, active children, adolescents, and young adults.

A cross-sectional sample of 6762 student-athletes completed BESS testing. Participants were stratified according to three age groups for each sex. The groups included the following: youth (age, 5-13 yr), males (n = 360), females (n = 246); high school (age, 14-18 yr), males (n = 3743), females (n = 1673); and college (age, 19-23 yr), males (n = 497), females (n = 243). Percentile rankings were determined for each participant to characterize movement of COM in the medial-lateral, anterior-posterior, and trunk rotation directions relative to the entire cohort during the BESS stances.

Overall, postural stability was worse in youth compared with high school and collegiate athletes. Specifically, the CC-PSI was significantly worse in youth male athletes compared with high school and collegiate male athletes (P < 0.001). Females exhibited significantly better scores compared with males in youth and high school cohorts (P < 0.01).

The CC-PSI provides a quantitative, objective measure of postural stability, overcoming the limitations associated with conventional BESS scoring. Optimal concussion management should use objective age- and sex-specific values in the evaluation of postural stability. The normative values of the CC-PSI may be used in the absence of a baseline BESS evaluation to aid clinical decision making.