Resultant Effects of Head Impacts on Vestibular Function Among NCAA Division 1 Male Lacrosse Players

Context: Few studies have evaluated the cumulative effects of the number and magnitude of head impacts on vestibular function among collegiate men\u27s lacrosse players. Objective: To determine theinfluence of the total number of head impacts (THI), peak linear acceleration, and Head Injury Criteria (HIC) score on vestibular ocular reflex (VOR) function after one competitive collegiate lacrosse season. Design: Prospective cohort. Setting: Combined field-based and laboratory study. Patients or Other Participants: 41 male NCAA Division I lacrosse players (age = 20.6 ± 1.4 yrs, height = 181.9 ± 6.6 cm). Interventions: Head impact measures were collected with the GForce Tracker(TM) system, and included total number of head impacts greater than 20 g (THI), magnitude of head impacts as assessed by peak linear acceleration, and Head Injury Criteria (HIC) score. Paired samples t-tests were used to compare thepretest and posttest VOR results. A multiple regression approach was used to explore the contributions of accelerometer variables, participant-reported number of previous concussions, and symptom severity during VOR testing to the post-season VOR measurements (α = 0.05). Main Outcome Measures: VOR parameters, as assessed by the inVision(TM) system included: maximum gaze velocity of the gaze stabilization test (GST) yaw, visual acuity difference of the dynamic visual acuity test (DVA) for pitch and yaw head movements, and absolute change in directional bias for each test. Results: A total of 8,648 impacts were recorded during the 2015 NCAA lacrosse season among the 32 athletes who participated in the post-season VOR assessments. Multiple regression analyses indicated that the total number (mean, 270.3 + 158.2), peak linear acceleration (mean, 50.9 + 158.2 g), HIC score (mean, 33.9 + 38.3), and symptom severity (mean, 2.35 + 2.97) were not significantly related to the changes observed in vestibular function (R = 0.201 to 0.535, P \u3e 0.05). However, participant-reported number of previous concussions was significantly related to the absolute change in directional bias during the GST (P = .036). Theabsolute change in directional bias of participants\u27 vestibular system was 6.64 + 19.57 for GST, 2.25 + 10.73 for DVA pitch, and 2.90 + 8.03 for DVA yaw (P \u3e 0.05). Conclusions: Participant reported concussion history had the greatest influence on changes in VOR directional bias measures and vestibular asymmetry in collegiate male lacrosse players over the course of one competitive season. These findings support the inclusion of vestibular assessment and treatment in concussion management protocols to improve patient care and health related quality of life among lacrosse participants with previous medical histories of concussion. Supported by a Southwest Athletic Trainers\u27 Association Graduate Student Research Grant