Abstract:
Background:
Impairments in balance or postural control are common following sport-related concussion (SRC). The Balance Error Scoring System (BESS) is widely utilized to assess static postural stability, but laboratory-based balance measures have been shown to more accurately detect changes in postural control.
Hypothesis/Purpose:
To determine whether postural control improved between presentation to the sports medicine clinic and return-to-sport (RTS) initiation, and whether this trend mirrored symptom scores and cognitive performance. A secondary aim was to assess whether changes in postural control were more accurately captured with center of pressure (COP) based measures compared to BESS.
Methods:
Patients diagnosed with a SRC were tested within 10 days of presentation (V0) and when cleared by a physician to begin a RTS protocol (V1). Clinical measures included Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) and the King-Devick (K-D) test. The BESS was performed with eyes closed while standing barefoot on a force platform for 6 conditions: double-limb stance, single-limb stance, and tandem stance on both firm and foam surfaces. BESS scores and total balance time were recorded for each condition, and COP-based measures were computed for both double-limb stance conditions (Table 1). Sample entropy was computed to quantify COP regularity over time with increased values indicating improvement in postural control. Wilcoxon signed-rank tests were performed to determine significance between visits (α<0.05).
Results:
Forty patients (17 males, 13.8±2.0 years) were included for analysis. ImPACT verbal and visual memory scores improved by 10% and 12%, respectively, total symptom score decreased (V0 18.03±13.85, V1 0.97±2.08; p<0.01), and visual motor speed and reaction time were both 11% faster on the K-D test. For postural control, the BESS indicated significant improvement given the reduction in errors on both surfaces (Firm Total: V0 3.23±2.09, V1 2.25±2.11, p=0.01; Foam Total: V0 7.38±2.05, V1 6.08±1.76, p<0.01; Table 1). Similarly, COP-based measures exhibited better overall balance between visits (Figure 1), primarily in the medial-lateral direction on the firm and the anterior-posterior direction on the foam. Lastly, sample entropy improved between visits, indicating more effective postural control.
Conclusion:
Significant improvement in postural control was observed during the recovery period which mirrored improvement in symptom scores and cognitive performance. Additionally, while COP-based measures showed similar trends to the BESS, they provided more detailed information in regards to balance recovery. Specifically, findings from the double stance condition highlight the utility of a more advanced assessment of postural control for determining RTS readiness following a SRC.