Balance Error Scoring System: Important Tool in Assessing Concussion

One of the signs of concussion is poor balance (what doctors call "postural instability"), which published studies have shown last approximately 72 hours (3 days) folowing sport-related concussion.¹ 

An athlete's balance and equilibrium can be tested through use of the Balance Error Scoring System (BESS).

The BESS consists of 3 tests lasting 20 seconds each, performed on two different surfaces, firm and foam:

• The athlete first stands with the feet narrowly together, the hands on the hips, and the eyes closed (double leg stance). The athlete holds this stance for 20 seconds while the number of balance errors (opening the eyes, hands coming off hips, a step, stumble or fall, moving the hips more than 30 degrees, lifting the forefoot or heel, or remaining out of testing position for more than 5 seconds) are recorded.
• The test is then repeated with a single-leg stance using the non-dominant foot, and
• A third time using a heel-toe stance with the non-dominant foot in the rear (tandem stance).
• All three tests are performed on a firm surface (grass, turf, court), and again on a piece of medium-density foam (a piece of foam can easily be carried in a travel trunk or equipment bag for road games).

Balance testing is considered by the 3rd Consensus Statement on Concussion in Sport¹ to be a "useful tool for objectively assessing" neurological functioning and a "reliable and valid addition to the assessment of athletes suffering from concussion, particularly where symptoms or signs indicate a balance component."   It is part of the updated Sports Concussion Assessment Tool issued (SCAT2) issued in conjunction with the Consensus Statement.

While there are other ways of assessing balance, such as machines that measure the amount of sway or rocking a person does when standing in certain positions, those machines and the accompanying computer software are expensive and are often cost-prohibitive for smaller, less well-funded athletic programs.  While less expensive alternatives may become available (including the Wii Fit video game player) may be used to asess balance, the modified BESS is, says William P. Meehan, III, MD, Director of the Sports Medicine Clinic at Children's Hospital Boston and a MomsTeam concussion expert, "is the most thoroughly studied, most easily understood, and most readily available for use in managing sport-related concussions."⁴

AAP recommendations

On the basis of studies showing the BESS to have a practice effect, and also that it seems to be affected not only by the environment in which the test is conducted but also by how soon after exercise the test is given, the American Academy of Pediatrics' statement on concussions recommends²  that the post-concussion testing be performed more than 15 minutes after cessation of exercise, and in a setting in which follow-up assessments can be performed instead of on a noisy sports sideline.   As Dr. Meehan notes, the BESS is best used where a baseline BESS score is obtained prior to the start of the season, when an athlete is healthy.  Then, repeated scores after concussion can be used to monitor recovery.

Poor balance and dizziness are different

Balance problems are often linked to dizziness as objective and subjective impairments of similar nervous system functioning. Dizziness can be the result of multiple organic reasons, including disturbances in vestibular (ie. vertigo), visual, or cardiovascular (ie. fainting) systems. 

While postural stability and balance can be tested objectively such as Romberg, tandem walking, heel-to-toe, BESS, Clinical Test of Sensory Interaction and Balance (CTSIB), and biomechanical force-plate testing, there is no consensus measure of dizziness, which is typically measured using postural/balance testing, self-report dizziness questionnaires, or both.  

A 2011 study³ found that dizziness, but not imbalance, was a risk factor for protracted recovery from concussion.  The finding prompted the authors, researchers at the University of Pittsburgh, to suggest that postural/balance testing and dizziness tests shoudl be looked at individually, that postural/balance testing should not be used as a proxy for dizziness, and that clincians should use dizziness questionnaires to augment post-concussion assessment in addition to neurocognitive tests, symptom reports, and postural/balance tests.  

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2. Halstead, M, Walter, K. "Clinical Report - Sport-Related Concussion in Children and Adolescents"  Pediatrics. 2010;126(3): 597-615 at nn. 52-57.

3. Lau BC, Kontos AP, Collins MW, Mucha A, Lovell MR. Which On-Field Signs/Symptoms Predict Protracted Recovery From Sport-Related Concussion Among High School Football Players? Am J. Sports Med 2011;20(10) DOI:10.1177/0363546511410655 (published June 28, 2011 online ahead of print)(accessed November 5, 2011). 

4. Meehan WP, III. Kids, Sports, and Concussions (Praeger 2011), p. 71.