Diagnostic Validity of Static and Dynamic Postural Assessments Within 24-48 Hours Post-Concussion

An estimated 1.6 - 3.8 million concussions occur annually in the United States [1]. Approximately 30% of sport-related concussions (SRC) experience postural instability immediately post-injury, while 75.6% report dizziness as a debilitating symptom [2,3]. Postural instability post-SRC has been well documented using numerous methods [3]. Kinetic quiet stance measures observed that concussed athletes have elevated postural sway magnitude and greater sway velocity within 24-48 hours post-SRC [4]. In addition, postural instability has been noted within 48-96 hours post-SRC using complex dual-task and dynamic assessments [5]. However, very little is known about the diagnostic validity of these postural assessments post-SRC. The purpose of this study is to investigate the diagnostic validity of two postural stability methods, quiet upright stance and a sport-like postural task, within 24-48 hours post-SRC

Repetitive head impacts do not affect postural control following a competitive athletic season

Evidence suggests that Repetitive Head Impacts (RHI) directly influence the brain over the course of a single contact collision season yet do not significantly impact a player\u27s performance on the standard clinical concussion assessment battery. The purpose of this study was to investigate changes in static postural control after a season of RHI in Division I football athletes using more sensitive measures of postural control as compared to a non-head contact sports. Fourteen Division I football players (CON) (age = 20.4 ± 1.12 years) and fourteen non-contact athletes (NON) (2 male, 11 female; age = 19.85 ± 1.21 years) completed a single trial of two minutes of eyes open quiet upright stance on a force platform (1000 Hz) prior to athletic participation (PRE) and at the end of the athletic season (POST). All CON athletes wore helmets outfitted with Head Impact Telemetry (HIT) sensors and total number of RHI and linear accelerations forces of each RHI were recorded. Center of pressure root mean square (RMS), peak excursion velocity (PEV), and sample entropy (SampEn) in the anteroposterior (AP) and mediolateral (ML) directions were calculated. CON group experienced 649.5 ± 496.8 mean number of impacts, 27.1 ± 3.0 mean linear accelerations, with ≈ 1% of total player impacts exceeded 98 g over the course of the season. There were no significant interactions for group x time RMS in the AP (p = 0.434) and ML (p = 0.114) directions, PEV in the AP (p = 0.262) and ML (p = 0.977) directions, and SampEn in the AP (p = 0.499) and ML (p = 0.984) directions. In addition, no significant interactions for group were observed for RMS in the AP (p = 0.105) and ML (p = 0.272) directions, PEV in the AP (p = 0.081) and ML (p = 0.143) directions, and SampEn in the AP (p = 0.583) and ML (p = 0.129) directions. These results suggest that over the course of a single competitive season, RHI do not negatively impact postural control even when measured with sensitive non-linear metrics

ASB clinical biomechanics award winner 2016: Assessment of gaze stability within 24–48 hours post-concussion

Background Approximately 90% of athletes with concussion experience a certain degree of visual system dysfunction immediately post-concussion. Of these abnormalities, gaze stability deficits are denoted as among the most common. Little research quantitatively explores these variables post-concussion. As such, the purpose of this study was to investigate and compare gaze stability between a control group of healthy non-injured athletes and a group of athletes with concussions 24–48 hours post-injury. Methods Ten collegiate NCAA Division I athletes with concussions and ten healthy control collegiate athletes completed two trials of a sport-like antisaccade postural control task, the Wii Fit Soccer Heading Game. During play all participants were instructed to minimize gaze deviations away from a central fixed area. Athletes with concussions were assessed within 24–48 post-concussion while healthy control data were collected during pre-season athletic screening. Raw ocular point of gaze coordinates were tracked with a monocular eye tracking device (240 Hz) and motion capture during the postural task to determine the instantaneous gaze coordinates. This data was exported and analyzed using a custom algorithm. Independent t-tests analyzed gaze resultant distance, prosaccade errors, mean vertical velocity, and mean horizontal velocity. Findings Athletes with concussions had significantly greater gaze resultant distance (p = 0.006), prosaccade errors (p \u3c 0.001), and horizontal velocity (p = 0.029) when compared to healthy controls. Interpretation These data suggest that athletes with concussions had less control of gaze during play of the Wii Fit Soccer Heading Game. This could indicate a gaze stability deficit via potentially reduced cortical inhibition that is present within 24–48 hours post-concussion