Concussion is associated with altered preparatory postural adjustments during gait initiation

Abstract

Gait initiation is a useful surrogate measure of supraspinal motor control mechanisms but has never been evaluated in a cohort following concussion. The aim of this study was to quantify the preparatory postural adjustments (PPAs) of gait initiation (GI) in fifteen concussion patients (4 females, 11 males) in comparison to a group of fifteen age- and sex-matched controls. All participants completed variants of the GI task where their dominant and non-dominant limbs as the 'stepping' and 'support' limbs. Task performance was quantified using the centre of pressure (COP) trajectory of each foot (computed from a force plate) and a surrogate of the centre of mass (COM) trajectory (estimated from an inertial measurement unit placed on the sacrum). Concussed patients exhibited decreased COP excursion on their dominant foot, both when it was the stepping limb (sagittal plane: 9.71mm [95% CI: 8.14-11.27mm] vs 14.9mm [95% CI: 12.31-17.49mm]; frontal plane: 36.95mm [95% CI: 30.87-43.03mm] vs 54.24mm [95% CI: 46.99-61.50mm]) and when it was the support limb (sagittal plane: 10.43mm [95% CI: 8.73-12.13mm] vs 18.13mm [95% CI: 14.92-21.35mm]; frontal plane: 66.51mm [95% CI: 60.45-72.57mm] vs 88.43mm [95% CI: 78.53-98.32mm]). This was reflected in the trajectory of the COM, wherein concussion patients exhibited lower posterior displacement (19.67mm [95% CI: 19.65mm-19.7mm]) compared with controls (23.62mm [95% CI: 23.6-23.64]). On this basis, we conclude that individuals with concussion display deficits during a GI task which are potentially indicative of supraspinal impairments in motor control.

Sensor-Based Balance Measures Outperform Modified Balance Error Scoring System in Identifying Acute Concussion

“…While inertial sensors have been proposed for objective, clinical measures of balance 20 and validated with laboratory force platforms, 34,55 there are few studies that have used inertial sensor technology to quantify balance 10,15,28 or gait 9,12,22 after concussion. The current evidence from these studies is relatively consistent in showing that inertial sensor-based measures can detect abnormal balance or gait when clinical tests may not.…”

Multiple Concussions Increase Odds and Rate of Lower Extremity Injury in National Collegiate Athletic Association Athletes After Return to Play

“…Furthermore, sensitive examination of balance and gait seems to corroborate these findings, as postconcussion athletes have measurable deficits in these metrics long after documented RTP. 12,17,20 These results suggest the need for improvements in modern concussion RTP protocols as well as further study on the pathophysiological process of concussion.…”

Understanding the Consequences of Repetitive Subconcussive Head Impacts in Sport: Brain Changes and Dampened Motor Control Are Seen After Boxing Practice

“…Increased GABAergic inhibitory activity should dampen the neural drive to the muscles, resulting in a measurable reduction in motor unit firing rate (Watanabe et al, 2002). Changes in motor control have been demonstrated following subconcussive head impacts (Haran et al, 2013; Kawata et al, 2016; Hwang et al, 2017) and concussion, specifically in balance (Powers et al, 2014), gait (Doherty et al, 2017) and vestibular function (Cheever et al, 2018). Evidence for acute impairments in neuromuscular control is particularly important because it may also explain why athletes returning to play following a concussion are more susceptible to musculoskeletal injuries than a healthy population (Lynall et al, 2015; Cross et al, 2017).…”