Optimizing Order of Administration for Concussion Baseline Assessment Among NCAA Student-Athletes and Military Cadets

Background Concussion pre-injury (i.e., baseline) assessments serve as a benchmark comparison point in the event an individual sustains a concussion and allows clinicians to compare to post-injury measures. However, baseline assessments must reflect the individual's true and most optimized performance to serve as a useful comparison. Mental fatigue and motivation throughout baseline testing may alter individual assessment performance, indicating an order of administration (OoA) may play an influential role in assessment outcomes. Objective To examine the influence concussion baseline battery OoA has on symptom, postural stability, cognitive screening, and computerized neurocognitive test outcomes. Methods We employed a retrospective observational cohort study to examine healthy collegiate student-athletes and military cadets (n = 2898, 19.0 +/- 1.4 years, 66.1% male, 75.6% white, 54.4% Division-I) baseline assessment performance on the Sport Concussion Assessment Tool (SCAT; total symptom number and severity), Balance Error Scoring System (BESS; total error scores), Standardized Assessment of Concussion (SAC; total score), and Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) domain scores (verbal and visual memory, visual-motor speed, reaction time). Assessments were binned to beginning, middle, or end tertiles based upon OoA. We used one-way ANOVAs with Tukey post-hoc t tests, 95% confidence intervals (CI), and Cohen's d effect sizes for significant models (alpha = 0.05). Results SCAT total symptom number (mean difference = 2.23; 95% CI 1.76-2.70; d = 0.49, p < 0.001) and severity (mean difference = 5.58; 95% CI 4.42-6.74; d = 0.50; p < 0.001) were lower when completed at the end of baseline testing compared to the middle. Total BESS errors were 1.06 lower when completed at the middle relative to the end (95% CI 0.43-1.69; d = 0.17; p = 0.001). Total SAC scores were better at the beginning relative to middle (mean difference = 0.58; 95% CI 0.25-0.90; d = 0.33; p < 0.001) and end (mean difference = 0.44; 95% CI 0.16-0.73; d = 0.24; p = 0.001). Verbal memory, visual memory, and reaction time performance were highest at the beginning (p <= 0.002), while visual-motor speed performance was highest at the middle (p = 0.001). Conclusion Completing baseline assessments in the order of (1) ImPACT, (2) SAC, (3) BESS, and (4) SCAT symptom checklist may improve performance across assessments collectively. Clinicians and researchers should consider completing baseline assessments in this order when possible to potentially aid in optimizing concussion baseline assessment performance and maximize post-concussion comparisons.