The aim of this study was to validate a portable method of objectively quantifying postural stability using accelerometer and gyroscopic data from the iPad2 during BESS.Design
Participants completed the six 20 s BESS conditions. BESS errors were recorded by trained evaluators. Linear and angular acceleration were simultaneously collected via the iPad2 accelerometer and gyroscope.Setting
Academic medical center.Participants
Fifty healthy participants aged 14–25 with no concussion in previous 6 months.Main Outcome Measurements
The primary outcome measures were evaluator-reported errors and natural-logarithmic volume of a 3D ellipsoid (iVE) encompassing 95% of postural sway data. The iVE characterises movement along anterior–posterior, medial-lateral, and trunk-rotational movement axes. It was hypothesised that iVE would provide a more sensitive assessment of postural stability than traditional BESS error scoring.Results
For the two double-leg stance conditions, BESS error scores were nearly identical, as few participants made errors. However, iVE data indicated a significant difference in stability between these conditions, as iVE for double-leg stance on firm surface was 0.3±0.16 s3 while iVE on foam was 3.4±0.16 s3.Conclusions
The objective data gathered using a consumer electronics device provides a reliable and valid assessment of postural stability and increases the sensitivity of the BESS. Accordingly, it is recommended that all six BESS conditions be completed in order to fulfill the current Zurich recommendation of a comprehensive balance assessment. We are currently using the ‘C3 App’ and BESS in the collection of baseline data in 12 000 high school and college athletes.