852 FO47 – Preseason cervical spine, vestibulo-ocular reflex, oculomotor, and dynamic balance measures informing the prevention of recurrent concussion in adolescent sport participants

Background Concussion history is a risk factor for recurrent concussion. Identification of differences in clinical outcomes by concussion history will inform future individually targeted prevention programs. Objective To examine the association between concussion history and clinical measures in adolescent (10–19 years) sport participants. Setting Adolescent sport (Canada) Design Cross-sectional Participants 1653 adolescents [males=988 (59.77%); females=653 (39.50%); undisclosed=12 (0.73%)] participating in a prospective cohort study. Assessment of Risk Factors Generalized estimating equations were used to examine the association between number of previous concussions and clinical outcomes. Covariates included age, sex, baseline symptom severity score, and sport-type. Main outcomes Cervical [Range of motion (ROM), flexor endurance (CFE), flexion-rotation (CFRT), head perturbation (HPT)], vestibulo-ocular reflex [Head thrust (HTT), dynamic visual acuity (DVA)], oculomotor [Symptom provocation/performance-smooth pursuit (SP), horizontal saccades (HS), vertical saccades (VS), near-point-convergence (NPC)], dynamic balance [Combined functional gait assessment (C-FGA)]. Results Adolescents reporting one previous concussion had a 2-fold greater-odds of VS symptom provocation (OR=2.02;95%CI:1.09–3.76) than adolescents with no history. Adolescents with 2+concussions had a 2-fold greater-odds of abnormal NPC performance (OR=2.02;95%CI:1.09–3.76), however, had fewer errors on the C-FGA (-0.14 errors;95%CI:-0.58--0.30). Females with a concussion history had poorer outcomes than males. Males with one previous concussion had a 48% reduced-odds of a positive CFRT (OR=0.52;95%CI:0.27–0.99) and males with 2+concussions had an 80% reduced-odds of a positive HTT (OR=0.20; 95%CI:0.14–0.68). Females with one concussion had a 3.4-fold greater-odds of a positive HTT (OR=3.40;95%CI:1.24–9.31). Females with 2+concussions had a 4-fold greater-odds of HS symptom provocation (OR=4.08;95%CI:1.56–10.65), 2.25-fold greater-odds of abnormal VS performance (OR=2.25;95%CI:1.30–3.92), and 4.64-fold higher-odds of a positive HTT (OR=4.64;95%CI:1.03–20.80). No associations with concussion history were found when examining ROM, CFE, HPT, DVA, or SP. Conclusion Future research to develop and evaluate prevention strategies targeting alterations in cervical, vestibulo-ocular, oculomotor, and balance function following an adolescent concussion will inform recurrent concussion prevention.