Sports Medicine Research: In the Lab & In the Field: High-Tech Tools Do Not Always Create a Better Test (Sports Med Res)


Monday, May 13, 2013

High-Tech Tools Do Not Always Create a Better Test

Comparison of the balance accelerometer measure and balance error scoring system in adolescent concussions in sports

Furman G.T., Lin C-C., Ballanca, J.L., Marchetti G.F., Collins M.W., Whitney S.L. The American Journal of Sports Medicine. 2013; ahead of print.

Take Home Message: The balance error scoring system (BESS) test is more effective in assessing high school age students’ concussions compared to the Balance Accelerometer Measure (BAM) assessment. The tandem leg stances on firm and foam surface of the BESS test are the most sensitive and specific positions for the detection of a concussion.

Assessing balance after a concussion provides useful information not only for diagnosis and prognosis but also during the athlete’s return to play progression. Many clinicians evaluate balance with the balance error scoring system (BESS), which may be imprecise and susceptible to inter-rater error; however, it was specifically designed to assess concussion injuries. In contrast, the Balance Accelerometer Measure (BAM), which is assessed by the patient wearing small sensors, provides accurate balance assessments but was not designed to assess concussed athletes. Therefore, the purpose of this study was to compare the BAM test with the BESS test regarding the ability to detect differences in postural differences between 43 high school students with concussions compared to 27 age-matched controls. The authors divided the concussed students were placed divided into acute or nonacute groups based on whether they were tested within 2 weeks of their concussion injury. The BAM protocol consisted of 6 standing balance conditions for 45 seconds each  (i.e., standing on firm then foam surface with eyes open, standing on firm then foam surface with eyes closed, tandem stance on firm surface with eyes open then closed). A computer program then calculated the sway scores for each condition. The BESS test protocol is also 6 stances held for 20 seconds each (i.e., double leg eyes closed, single leg eyes closed, and tandem leg eyes closed first on firm followed by foam surface). A physical therapist used video recordings to total the errors scores for each position (e.g., out of position for more than 5 seconds, hands off iliac crest). The authors found that BAM sway scores – during eyes open/foam surface – weakly identified nonacute concussed athletes versus control participants. There was no difference in BAM sway scores between acutely concussed students and healthy controls. BESS scores were significantly higher in acute and subactute groups compared to the control group within both firm and foam tandem stances. Additionally, the acute group had higher scores than the subacute group. A total BESS score of 21 or more errors optimally identified patients in the acute concussion group compared to the control group (60% sensitivity, 82% specificity).

This study indicated that the BESS test is a more useful tool than the BAM assessment to determine balance problems in concussed high school students. The validity of BAM is supported by the fact that sway increased with eyes closed compared with eyes open and on a foam versus firm surface. However, among high school students BAM may not be optimal to detect the influence of a concussion on balance. The BESS test in this study was optimized by the help of video analysis and is sensitive enough to discriminate healthy persons from patients with concussions, especially within the tandem stances. The double leg stance had virtually no errors between all groups and researchers suggested that the BESS test could be improved by taking the double leg stance out of the assessment. Additionally, it was noted that the modified version used in the SCAT2 without the foam stance may not be able to discriminate healthy versus concussed athletes. Potentially BAM post concussion sway scores could be compared to baseline (preseason) sway scores and the difference may be more informative. 

Do you think video analysis of the BESS test is necessary to receive similar findings? Do you think taking the double leg stance out of the BESS test is a good idea?

Written by: Jane McDevitt MS, ATC, CSCS
Reviewed by: Jeffrey Driban

Related Posts:

Furman GR, Lin CC, Bellanca JL, Marchetti GF, Collins MW, & Whitney SL (2013). Comparison of the Balance Accelerometer Measure and Balance Error Scoring System in Adolescent Concussions in Sports. The American Journal of Sports Medicine PMID: 23585486


Post a Comment

When you submit a comment please click 'Subscribe by Email" (just below the comments) or "Subscribe to: Post Comments (Atom)" (at the bottom of this page) if you would like to receive a notification when another comment has been submitted to this post.

Please note that if you are using Safari and have problems submitting comments you may need to go to your preferences (privacy tab) and stop blocking third party cookies. Sorry for any inconvenience this may pose.