Instrumenting the balance error scoring system for use with patients reporting persistent balance problems after mild traumatic brain injury

Abstract

Objective: To determine whether alterations to the Balance Error Scoring System (BESS), such as modified conditions and/or instrumentation, would improve the ability to correctly classify traumatic brain injury (TBI) status in patients with mild TBI with persistent self-reported balance complaints.

Design: Cross-sectional study.

Setting: Outpatient clinic.

Participants: Subjects (n=13; age, 16.3±2y) with a recent history of concussion (mild TBI group) and demographically matched control subjects (n=13; age, 16.7±2y; control group).

Interventions: Not applicable.

Main outcome measures: Outcome measures included the BESS, modified BESS, instrumented BESS, and instrumented modified BESS. All subjects were tested on the noninstrumented BESS and modified BESS and were scored by visual observation of instability in 6 and 3 stance conditions, respectively. Instrumentation of these 2 tests used 1 inertial sensor with an accelerometer and gyroscope to quantify bidirectional body sway.

Results: Scores from the BESS and the modified BESS tests were similar between groups. However, results from the instrumented measures using the inertial sensor were significantly different between groups. The instrumented modified BESS had superior diagnostic classification and the largest area under the curve when compared with the other balance measures.

Conclusions: A concussion may disrupt the sensory processing required for optimal postural control, which was measured by sway during quiet stance. These results suggest that the use of portable inertial sensors may be useful in the move toward more objective and sensitive measures of balance control postconcussion, but more work is needed to increase sensitivity.

Trial registration: ClinicalTrials.gov NCT01377454.

Keywords: AP; AUC; BESS; Balance Error Scoring System; Brain concussion; Brain injuries; ML; NIH; National Institutes of Health; OHSU; Oregon Health & Science University; Postural balance; RMS; ROC; Rehabilitation; TBI; anterior-posterior; area under the curve; mTBI; mediolateral; mild traumatic brain injury; receiver operating characteristic; root-mean-square; traumatic brain injury.

Figure 1.

Opal sensor placement at L5.

Figure 2.

Frequency distributions for the 4 indicated balance tests; a) BESS, b) Mod. BESS, c) Inst. BESS, d) Inst. Mod. BESS. The rows of square symbols indicate mean values. The P-values are for 2-sample t-tests.

Figure 3.

Receiver Operator Characteristic curves for the True Positive Rate (TPR) and False Positive Rate (FPR) for each balance test.