Systematic Review of the Balance Error Scoring System
David R. Bell, Kevin M. Guskiewicz, Micheal A. Clark, and Darin A. Padua Sports Health: A Multidisciplinary Approach May/June 2011 vol. 3 no. 3 287-295
Many studies have demonstrated the importance of balance and balance training for activities of daily living and sport. For patients with severe balance deficiencies (e.g., post stroke) there are some well validated clinical measures (e.g., Berg Balance Scale, Tinetti Balance Assessment Tool) that do not require advance equipment (e.g., force plates). Among the athletic population there are very few balance assessments that incorporate multiple tasks, can be performed in a traditional clinical setting, and have been validated for several conditions. The Balance Error Scoring System (BESS), originally developed for assessing concussions, is one commonly used assessment consisting of three stances (feet together, single-leg stance, and tandem stance) performed on a firm and foam surface for 20 seconds each (the outcome score is based on the number of errors during the tasks). While the BESS has been used to assess other conditions and populations other than concussions it is unclear if the BESS can be used for this broader purpose. Therefore, Bell et al performed a systematic review of the reliability and validity of the BESS (included 20 articles). Intra-tester reliability (repeatability of a measure when one person does the measurements) for the total BESS score ranged from 0.60 to 0.92 (ideally this number is 0.80 or higher). Inter-tester reliability (determines if two testers will come up with similar scores) ranged from 0.57 to 0.85 (ideally this number is 0.80 or higher). Test-retest reliability (repeatability of the test over time) was moderate but one study reported that performing the BESS three times and averaging the scores provided excellent repeatability. The BESS scores were related to force-plate measures (particularly for the more challenging tasks), suggesting that the score may be a proxy for these measures. The review found that the BESS can detect differences between groups when there are large differences (concussions or fatigue) but not when the differences are more subtle. Furthermore, the BESS scores increase with age, are higher among patients with ankle instability, and improve after neuromuscular training.
This systematic review is helpful for looking at a commonly used balance assessment. The BESS can be a valuable tool for evaluating patients with suspected concussions and monitoring progression during a rehabilitation program. It’s interesting to note that while the BESS performs well (relates to similar measures and can detect noticeable differences) the reliability (repeatability) can vary greatly. This is one of the first items that the authors address in their discussion. They suggest that 1) clinicians and researchers should establish their reliability before using the BESS, 2) the same tester should be used over time to evaluate a patient, and 3) tester training can be helpful to establish consistency among multiple raters. The authors also note that performing the BESS three times and taking the average may be optimal. If you are using the BESS (or planning to) then the discussion of the article raises some helpful tips. In research, determining an evaluator’s reliability (repeatability) or agreement with another evaluator is the norm but this is often neglected in the clinical practice. This can become especially important in sports medicine clinics that have multiple clinicians evaluating the same patient over time. This may seem like a nit-picky item but performing these reliability tests (by comparing your results to another clinician or your results on multiple occasions) may lead to improved training and communication, recognition of tests that are not performing well, as well as less errors in evaluating patients. Have you ever tested how consistent you perform a particular test or how your results compare to another clinician? Try it…you might be surprised.
Written by: Jeffrey Driban
Reviewed by: Stephen Thomas