Abstract
The potential postural control differences in acute vs. chronic concussion are poorly understood. This study evaluated quiet stance postural control at baseline and at 72-hours, 2-weeks, and 1-month post-concussion (n=7), and in individuals with a history of 0 (n=31) versus 3+ (n=13) concussions. We compared changes in root-mean-square displacement (RMSd) and mean velocity of centre-of-pressure (COPvel) in the anterior/posterior (AP) and medial/lateral (ML) directions. RM-ANOVA indicated a main effect of time for all outcomes in acutely concussed participants: AP-RMSd (p=0.006), AP-COPvel (p=0.012), ML-RMSd (p=0.001), and ML-COPvel (p=0.001). Pairwise comparisons indicated reductions, relative to baseline, in AP-RMSd (p=0.050) and AP-COPvel (p=0.039) at 2-weeks post-injury, while ML-RMSd was reduced at 1-month (p=0.021). Change scores from baseline to 72-hours were correlated between: AP-RMSd and SCAT3 Balance Error Scoring System (r=0.878, p=0.009), AP-COPvel and Standardized Assessment of Concussion (SAC) (r=-0.822, p=0.023), and ML-COPvel and SAC (r=-0.836, p=0.019). In contrast to these acute effects, there were no effects of concussion history on balance metrics. Mixed ANOVA indicated a significant condition effect in ML-RMSd (p=0.015) and ML-COPvel (p=0.025) between eyes-open and eyes-closed conditions in the history of concussion comparison. Therefore those ML variables were sensitive to condition and indicate that frontal plane COP movements may be more sensitive than those in the sagittal plane. Taken together, the present data suggests alterations in COP sway during quiet stance persist for up to one-month following concussion, but a history of multiple concussions does not appear to induce long-term balance control deficits.
