THE EFFECT OF RECENT CONCUSSION ON BALANCE DURING SINGLE AND DUAL TASKS IN ADOLESCENTS

Purpose: Returning to normal activity without full recovery from concussion may make athletes with concussion more susceptible to a second more severe concussion. Dual-task balance testing has been suggested to provide better assessment of when to return to normal activity. The purpose was to explore changes during single and dual-task balancing conditions over time and to compare sway between adolescents with and without Sports-related Concussion (SRC).\ud Participants: 25 adolescents (mean age 15.1±1.9 y) with SRC within the past 10 days and 22 matched controls (mean age 15.9±2.1 y).\ud Materials/Methods: Adolescents with SRC were assessed 3 times: within 10 days of injury, within 14-27 days after injury, and when cleared from concussion. Controls were assessed once. Sway was assessed using a force plate while subjects stood feet-apart on firm or foam surfaces. Balance tests were performed under single-task (without cognitive-task) and dual-task conditions (with cognitive-task). The cognitive-task was a visual reaction time test where adolescents pressed a thumb-switch that either corresponded to the side of the monitor where a rectangle appeared (simple cognitive-task), or corresponded to the direction an arrow was pointing that appeared on either side of the monitor (complex cognitive-task). The dependent variables were the root mean square (RMS) and the normalized path length (NPL) of the sway. A linear mixed model was performed to investigate the main effects and interactions of group, visit, dual-task, cognitive-task, and surface on sway.\ud Results: The main findings were: no difference in sway between the SRC and control groups; no difference in sway among visits in the SRC group; a dual-task effect that produced reduced NPL sway and greater RMS sway compared with the single-task; increased RMS sway during the perceptual inhibition task compared with the spatial discrimination task; and increased sway during the foam conditions compared with firm surface, which was dependent on the subject groups.\ud Conclusions: Contrary to previous research, no differences in balance performance were observed between groups with and without SRC, or over time in adolescents with SRC, indicating that the type of dual-task may be an important factor in assessing return to normal activity