Balance markers and saccadic eye-movement measures in adolescents with Postconcussion Syndrome

Context Deficits in both balance and oculomotor function, including impairments in saccadic eye movements, are observed in approximately 30% of patients postconcussion. Whereas balance and saccadic eye movements are routinely assessed separately, growing evidence suggests that they should be assessed concurrently. Objective To compare balance measures and saccades between adolescents 1 to 3 months postconcussion and healthy uninjured adolescents. Design Case-control study. Setting Concussion clinic and 2 private schools. Patients or Other Participants Twenty-five adolescents (10 boys, 15 girls; median [interquartile range (IQR)] age = 14 years [11.5–16 years]) between 1 and 3 months postconcussion (median [IQR] time since injury = 39.5 days [30–56.75 days]) and 33 uninjured adolescents (18 boys, 15 girls; median [IQR] age = 13 years [11.5–14 years]). Main Outcome Measure(s) The center-of-pressure 95% ellipse area and medial-lateral and anterior-posterior velocity and the number of saccades in the dual-task balance conditions including a high cognitive load (cognitive condition), a low cognitive load and a gaze-shifting component (visual condition), or both a high cognitive load and a gaze-shifting component (combined condition). Results Concussion-group participants swayed over larger center-of-pressure ellipse areas in the visual (P = .02; effect size = 0.73) and combined (P = .005; effect size = 0.86) conditions but not in the cognitive condition (P = .07; effect size = 0.50). No group differences were identified for anterior-posterior (F1,56 = 2.57, P = .12) or medial-lateral (F1,56 = 0.157, P = .69) velocity. Concussion-group participants also did not perform more saccades than the control-group participants (F1,56 = 2.04, P = .16). Conclusions Performing dual-task balance conditions for which the secondary task involves a gaze-shifting component or both a gaze-shifting component and a high cognitive load resulted in greater sway amplitude in adolescents with concussion. However, these larger amounts of postural sway were not associated with increased saccadic eye movements.