Repetitive head impacts (RHI), independent of concussion, can lead to alterations in brain activity and function, specifically within the midbrain, which can manifest as abnormal eye movements. PURPOSE: To evaluate the effect of repetitive head impacts on eye movements during a head stationary dynamic visual acuity (sDVA) task. METHODS: 11 NCAA Division I athletes [5 FB: all males; average age 21 years; 6 cross country (XC) athletes (3 females, 3 males; average age 20 years] participated in this study. Any athlete was excluded due to any existing non-corrected vision impairment, self-reported prior concussion history, and withdrawal from their sport due to injury or sickness. FB players had to sustain 20 impacts per week ≥10gs for inclusion. Student-athletes were assessed prior (PRE) to the start, in the middle (MID) and within 2-weeks of the conclusion of the season (POST) on an adaptive sDVA task. FB players wore instrumented mouthguards to track head impacts that were independently video verified. At each testing time point, participants completed 60 randomized trials of smooth pursuit (SPEM) (30°/s) and saccadic (90°/s) eye movements. Participants' eye movements were monitored (500Hz; Eyelink SR research, Ottawa, CN) while their heads were stabilized in a chin rest at a distance of 154cm from the 26° visual field monitor. Participants' task was to track the gap location (left, right, up, down) in a Landolt-C that moved across the screen (horizontally left to right). Using a 2-up-1-down staircase method the size of the stimulus and the gap varied based on the correct/incorrect responses during both smooth pursuit and saccadic trials. The primary measures were SPEM gain and saccadic mean velocity.
Tandem gait is becoming a widely used sideline tool to evaluate dynamic postural control following sport-related concussion (SRC). Little to no research has evaluated tandem gait center of pressure (COP) following SRC compared to the traditional temporal characteristics. PURPOSE: Compare the differences from baseline to acute SRC post-injury using temporal and COP metrics in tandem gait. METHODS: 8 NCAA Division 1 athletes (age=20±1 years) performed tandem gait prior to their competitive season (PRE) and within 24-48 hours post-injury (POST) using an instrumented walkway (30Hz, Tekscan Strideway, Tekscan Inc., South Boston, MA). The head team physician independently verified and diagnosed the SRC. During tandem gait, student-athletes were instructed to walk 3-meters, turning en pointe, and returning to the start position walking heel-to-toe as fast as possible. Three randomized trials of single-task (ST) and dual-task (DT) were completed and the raw center of force from the Strideway was exported and further analyzed. COP excursion in the mediolateral (ML) and mean velocity in the anteroposterior (AP and ML directions were calculated using a custom MATLAB code along with time to completion were evaluated during the entire trial. Multiple RM ANOVAs compare the baseline to post-injury tandem gait. RESULTS: There were no significant differences for ST ML excursion (PRE=2.78±0.47, POST= 3.61±1.9; p=0.25), for ST ML velocity (PRE=16.57±4.38, POST=22.83±17.68; p=0.30), for ST AP velocity (PRE=82.15±16.12, POST=107. 82±64.29; p=0.196), and for ST time (PRE=9.9±1.81, POST=11.82±3.45; p=0.62).
CONCLUSION:The results indicate there are no significant differences between PRE and POST SRC. Although the data does not show any significant difference between times, SRC does generally slow an individual's velocity thus suggesting a causal relationship exists.
194Long-term Impairments In Cognition And Balance In Women With Post-concussion Syndrome
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