Longitudinal assessment of fluid cognitive function and cognitive fatigue in adolescents with concussion and orthopedic injury: A Pediatric Assessment of Rest and Exertion (PedCARE) study.

UNLABELLED: Objective: Examine differences in fluid cognition and multidimensional fatigue between youth with concussion and orthopedic injury (OI) at 72-hr and 4-week postinjury and explore the association between fatigue and fluid cognition and cognitive symptoms in each group. METHOD: This secondary analysis of the Pediatric Concussion Assessment of Rest and Exertion randomized controlled trial of children aged 10-17.99 years who presented to the emergency department ≤48 hr of a concussion or OI. The National Institutes of Health Toolbox assessed fluid cognition, Health and Behaviour Inventory measured cognitive symptoms, and Pediatric Quality of Life Multidimensional Fatigue Scale measured fatigue at 72 ± 48 hr and 4 weeks ± 5 days postinjury. RESULTS: Eighty-four concussion (Mdnage [interquartile range] = 12.41 [11.20-13.83] years, 47.6% female) and 32 OI participants (Mdnage [interquartile range] = 12.88 [11.67-14.42] years, 37.5% female) were included. Significant Group × Time interactions emerged for the Fluid Cognition Composite, Pattern Comparison, Picture Sequence, and Flanker Inhibitory tests (ps ≤ .048) and on all fatigue dimensions (ps < .001). At 72 hr, the concussion group performed worse than the OI on the Fluid Composite and Pattern Comparison tests (p ≤ .048) and reported higher fatigue than the OIs (ps ≤ .005), with differences resolving by 4 weeks. A group effect was found on Dimensional Change Card Sorting test (p = .007), with the concussion group performing worse than the OI group across time points (p = .003). No associations between Fluid Cognition Composite score and fatigue were observed (p ≥ .09). Greater total and cognitive fatigue were associated with higher cognitive symptom burden in the concussion group (p ≤ .001) but not in the OI group. CONCLUSIONS: Cognition and fatigue showed similar recovery trajectories, suggesting that they may recover in parallel. (PsycInfo Database Record (c) 2026 APA, all rights reserved).