Examining Motor Tasks of Differing Complexity After Concussion in Adolescents

Objectives (1) To determine the effects of concussion-related motor impairments at different task complexities in isolation and with a cognitive dual-task and (2) to determine if self-reported balance deficits after concussion are associated with gait, quiet stance, or cognitive dual-task impairments. Design Cross-sectional study. Setting Sports medicine clinic. Participants Adolescent athletes clinically diagnosed with a sport-related concussion and those without concussion. Forty-nine patients with concussion (mean age=14.9±1.9y; 51% female; tested 7.0±3.0d postinjury) and 65 control participants (mean age=14.9±1.6y; 52% female) completed the study (N=114). Interventions Athletes with concussion completed a single-task and dual-task standing and walking protocol within 14 days of injury and were compared to those without concussion. Main Outcome Measures Outcome measures included gait speed, quiet stance (root mean square [RMS] coronal/sagittal plane sway), and cognitive performance (accuracy). Dual-task costs were calculated as the percentage change between single-task and dual-task conditions. Participants with concussion were then stratified by those who did and did not report subjective balance problems at the time of testing and compared using objective balance and gait metrics. Results The concussion group walked slower during dual-task gait than controls (0.83±0.17 m/s vs 0.92±0.15 m/s; Cohen’s d=0.53). Dual-task quiet stance RMS sway values were similar for concussion and control groups in coronal (1.20±0.52 m/s-2 vs 1.26±0.65 m/s-2; d=0.09) and sagittal (0.56±0.24 m/s-2 vs 0.73±0.44 m/s-2; d=0.20) movement planes. The concussion participants with subjectively-reported balance problems had significantly greater walking speed dual-task costs than concussion participants without self-reported balance problems (-25±10% vs -19±9%; P=.02). Conclusions Following concussion, adolescents demonstrate slower gait speeds, but similar quiet stance values relative to those without concussion. The study results indicate that tasks requiring greater motor coordination may elicit greater alterations following a concussion.