accelerometer measure and balance error scoring system in adolescent
concussions in sports
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.
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.
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%
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?
by: Jane McDevitt MS, ATC, CSCS
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