On-field predictors of neuropsychological and symptom deficit following sports-related concussion

Objective: Investigate the relationship between on-field markers of concussion severity and postinjury neuropsychological and symptom presentation in an athlete-specific population. Design: Case control study. Setting: Multicenter analysis of high school and college athletes. Participants: A total of 78 athletes sustaining sports-related concussion were selected from a larger sample of 139 concussed athletes. Assessment of Predictor Variables: On-field presence of disorientation, posttraumatic amnesia, retrograde amnesia, and loss of consciousness. Main Outcome Measures: ImPACT, a computerized neuropsychological test battery, was administered pre-season and, on average, 2 days postinjury. Good postinjury presentation (n = 44) was defined as no measurable change, relative to baseline, in terms of both ImPACT memory and symptom composite scores. Poor presentation (n = 34) was defined as a 10-point increase in symptom reporting and 10-point decrease in memory functioning (exceeding the 80% confidence interval for measurement error on ImPACT). Athletes failing to meet good or poor selection criteria (n = 61) were not included in the analysis. Results: Odds ratios revealed that athletes demonstrating poor presentation at 2 days postinjury were over 10 times more likely (P < 0.001) to have exhibited retrograde amnesia following concussive injury when compared with athletes exhibiting good presentation. Similarly, athletes with poor presentation were over 4 times more likely (P < 0.013) to have exhibited posttraumatic amnesia and at least 5 minutes of mental status change. There were no differences between good and poor presentation groups in terms of on-field loss of consciousness. Conclusions: The presence of amnesia, not loss of consciousness, appears predictive of symptom and neurocognitive deficits following concussion in athletes. Athletes presenting with on-field amnesia should undergo comprehensive and individualized assessment prior to returning to sport participation. Continued refinement of sports concussion grading scales is war-ranted in lieu of consistent findings that brief loss of consciousness is not predictive of concussion injury severity.