Context: Pre-injury symptoms are predictive of time to clinical recovery following sport-related concussion. Somatization (preoccupation with somatic symptoms) has been invoked as an explanation. Symptom burden evinced at baseline may carry over to post-concussion, resulting in prolonged recovery. No reports have been published concerning the possibility that patients diagnosed with concussion may have elevated baseline symptom report.
Objective: To determine if high school athletes who are diagnosed with concussion have elevated symptom report levels at baseline compared to those who do not experience a concussion.
Design: Prospective cohort study.
Setting: High school athletic training facilities. Patients or Other Participants: 1229 adolescent athletes: concussed (male = 143, female = 50, age = 15.2 ± 1.3 years), and non-concussed (male = 777, female = 143, age = 15.2 ± 1.9) participating in 10 sports.
Interventions: Participants were selected from a database housing >70,000 Immediate Post-Concussion Assessment and Cognitive Testing (IMPACT) results from 84 high schools in Arizona. 193 concussed adolescents with baseline results within the one year prior comprised the Concussed group. 1036 subjects propensity-matched by sex, sport, and age comprised the Non-concussed group. Generalized linear (negative binomial) models compared baseline symptom severity for Concussed vs Non-concussed subjects. Sex was included as a factor. Mean scores and 95% confidence intervals, as well as effect sizes (ES: Cohen’s d), are reported.
Main Outcome Measures: Baseline total symptom severity scores (TSS) were calculated for IMPACT symptom domains, Physical, Cognitive, Emotion and Sleep, by summing endorsements of relevant items, rated 0 = none-to-6 = severe.
Results: Significant interactions between Concussion and Sex were identified for Physical and Emotional (p < 0.001), Cognitive (p = 0.001), and Sleep (p = 0.003). Concussed males showed higher mean (M) endorsement of Physical symptoms, M = 2.43 (95% CI: 2.00,2.95) than non-concussed, M = 1.21 (95% CI: 1.10,1.33), p < 0.001, ES = 0.58; whereas concussed females were lower, M = 1.28 (95% CI: 0.88,1.85) than non-concussed, M = 2.05 (95% CI: 1.77,2.38), p = 0.020, ES = -0.19. Concussed males showed higher endorsement of Cognitive symptoms, M = 1.17 (95% CI: 0.94,1.47) than non-concussed M = 0.67 (95% CI: 0.60,0.75), p < 0.001, ES = 0.40; concussed females, M = 0.58 (95% CI: 0.37,0.92) did not differ from non-concussed M=0.86 (95% CI: 0.72,1.03), p = 0.111, ES = -0.13. For Emotion, concussed males showed higher endorsement, M = 1.38 (95% CI: 1.11, 1.71) than non-concussed M = 0.93 (95% CI: 0.84,1.03), p = 0.001, ES = 0.30; however concussed females were lower, M = 0.80 (95% CI: 0.53,1.21) than non-concussed M = 2.07 (95% CI: 1.78,2.40), p < 0.001, ES = -0.31. Concussed males showed higher endorsement of Sleep symptoms, M = 1.90 (95% CI: 1.55, 2.33) than non-concussed M = 1.22 (95% CI: 1.11, 1.34), p = 0.001, ES = 0.36; concussed females, M = 1.28 (95% CI: 0.88,1.85,) did not differ from non-concussed, M = 1.65 (95% CI: 1.41,1.92), p = 0.216, ES = -0.10. 92.1% of the concussed and 94.4% of the non-concussed reported no prior concussions.
Conclusions: Elevated symptom report, in part personological, is essential to concussion diagnosis. An incident typically associated with concussion, e.g., a blow to the head might, more readily, result in a concussion diagnosis among athletes with high, persistent symptom report, even though the elevated symptoms have little to do with the impact. The unexpected difference between males and females requires further study.