Impact of Prior Brain Injury on Concussion Recovery in Military Personnel: Evaluation of Timing Between Concussions

The Interval Between Concussions Does Not Influence Time to Asymptomatic or Return to Play: A CARE Consortium Study

INTRODUCTION

The purpose of this study was to determine if the time interval between two concussive events influences the number of days to asymptomatic status, days to return to play, or performance on common post-concussion assessments following the second concussion.

METHODS

Data from 448 collegiate athletes and service academy cadets with two concussions (time between concussions: median 295.0 days [interquartile range: 125.0-438.2]), 40.0% female) were analyzed from Concussion Assessment Research and Education (CARE) Consortium institutions between 2014 and 2020. Days between concussions was the primary predictor variable. Primary outcome measures included time to asymptomatic and time to return to play following the second concussion. Secondary outcome measures included total number of symptoms, total symptom severity, Balance Error Scoring System total score, and Standardized Assessment of Concussion total score within 48 h of their second concussion.

RESULTS

Time between concussions did not significantly contribute to the multivariate time to asymptomatic (p = 0.390), time to return to play (p = 0.859), or the secondary outcomes (p-range = 0.165-0.477) models. Time to asymptomatic (p = 0.619) or return to play (p = 0.524) did not differ between same-season and different-season concussions. Sex significantly contributed to the return to play (p = 0.005) multivariate model. Delayed symptom onset and immediate removal from play/competition significantly contributed to the total number of symptoms (p = 0.001, p = 0.014) and symptom severity (p = 0.011, p = 0.022) multivariate models.

CONCLUSION

These results suggest that in a population with a large period between injuries, the time between concussions may not be relevant to clinical recovery.

Designing research on concussion treatment in the military setting: Important challenges to consider

Traumatic brain injury (TBI) is highly prevalent on a global scale with concussion being the most common of all TBIs. Concussion research on rehabilitation and symptom resolution is well-established, particularly among athletes, but less is known about the recovery of active duty service members (ADSMs). In a population whose occupational environment increases risk for such injury, it is imperative that treatment is optimized to achieve successful rehabilitation. The military setting, however, has challenges that must be accounted for when developing proposals to study the benefits of new interventions or treatment. This review will provide a discussion on those challenges to better understand the considerations that are essential during the developmental phase of concussion studies within the military setting. This review aims to provide investigators novice to the military setting an overview of considerations when researching concussion among ADSMs.