Setting boundaries: Utilization of time to boundary for objective evaluation of the balance error scoring system

ABSTRACT

Subjective evaluations of balance performance, like the modified Balance Error Scoring System (mBESS), are highly popular. Alternatively, quantitative measures may offer additional clarity in identifying balance dysfunction. A novel measure to define balance impairments is time to boundary (TTB), which represents the amount of time available to make corrective postural adjustments prior to the centre of pressure (CoP) reaching the edge of the base of support. The purpose of this investigation was to assess TTB and traditional measures of CoP displacement of young adults performing the mBESS on a BTrackS balance plate. Path length and TTB were calculated in anterior-posterior (AP) and medio-lateral (ML) directions, respectively. AP and ML path lengths were largest in Single stance (109.2 & 118.1 cm, respectively) and smallest in Dual stance (27.1 & 36.4 cm, respectively). The average AP and ML TTBs were higher in Dual (10.67 & 7.27 s, respectively) compared to Single (3.54 & 1.20 s, respectively) or Tandem (10.11 & 1.94 s, respectively) stances, and lower in Single stance compared to Tandem. Given the effect sizes for TTB were greater than those of path length in both directions, TTB more adequately differentiates these stance conditions than path length or subjective scores.

KEYWORDS:

• Balance Tracking Systems (BTrackS)
• Balance Error Scoring System (BESS); postural stability
• balance
• portable

Acknowledgments

The authors would like to thank graduate students Andrew S. Monaghan and Clayton W. Swanson for their assistance in the acquisition of data for this project.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.