Research

Background: The aim of this study was to quantify postural control ability in a group with concussion compared with a healthy control group. Method: Fifteen concussion patients (4 females, 11 males) and a group of fifteen age- and sex- matched controls were recruited. Participants were tested during the performance of the three stance variants (bilateral, tandem and unilateral stance) of the balance error scoring system standing on a force place, whilst wearing an inertial measurement unit placed at the posterior aspect of the sacrum. Findings: The area of postural sway was computed using the force-plate and the ‘95% ellipsoid volume of sway’ was computed from the accelerometer data. Concussed patients exhibited increased sway area (1513mm2 [95% CI: 935 to 2091mm2] vs 646mm2 [95%CI: 519 to 772mm2] p = 0.02) and sway volume (9.46m3s-6 [95%CI: 8.02 to 19.94m3s-6] vs 2.68m3s-6 [95%CI: 1.81 to 3.55m3s-6]) in the bilateral stance position of the balance error scoring system. The sway volume metric also had excellent accuracy in identifying task ‘errors’ (tandem stance: 95%CI: 85-96%, p < 0.001; unilateral stance: 95%CI: 86-96%, p < 0.001). Interpretation: Individuals with concussion display increased postural sway during bilateral stance. The sway volume that was calculated from the accelerometer data not only differentiated a group with concussion from a healthy control group, but successfully identified when task errors had occurred. This may be of value in the development of a pitchside assessment system for concussion.