Outcome Trends after US Military Concussive Traumatic Brain Injury

Abstract

Care for US military personnel with combat-related concussive traumatic brain injury (TBI) has substantially changed in recent years, yet trends in clinical outcomes remain largely unknown. Our prospective longitudinal studies of US military personnel with concussive TBI from 2008-2013 at Landstuhl Regional Medical Center in Germany and twp sites in Afghanistan provided an opportunity to assess for changes in outcomes over time and analyze correlates of overall disability. We enrolled 321 active-duty US military personnel who sustained concussive TBI in theater and 254 military controls. We prospectively assessed clinical outcomes 6-12 months later in 199 with concussive TBI and 148 controls. Global disability, neurobehavioral impairment, depression severity, and post-traumatic stress disorder (PTSD) severity were worse in concussive TBI groups in comparison with controls in all cohorts. Global disability primarily reflected a combination of work-related and nonwork-related disability. There was a modest but statistically significant trend toward less PTSD in later cohorts. Specifically, there was a decrease of 5.9 points of 136 possible on the Clinician Administered PTSD Scale (-4.3%) per year (95% confidence interval, 2.8-9.0 points, p = 0.0037 linear regression, p = 0.03 including covariates in generalized linear model). No other significant trends in outcomes were found. Global disability was more common in those with TBI, those evacuated from theater, and those with more severe depression and PTSD. Disability was not significantly related to neuropsychological performance, age, education, self-reported sleep deprivation, injury mechanism, or date of enrollment. Thus, across multiple cohorts of US military personnel with combat-related concussion, 6-12 month outcomes have improved only modestly and are often poor. Future focus on early depression and PTSD after concussive TBI appears warranted. Adverse outcomes are incompletely explained, however, and additional studies with prospective collection of data on acute injury severity and polytrauma, as well as reduced attrition before follow-up will be required to fully address the root causes of persistent disability after wartime injury.

Moderate blast exposure results in increased IL-6 and TNFα in peripheral blood

“…Blast exposures during deployment are a signature injury of the Operation Iraqi Freedom/Operation Enduring Freedom campaigns (Tanielian, 2008), which are linked to chronic neurological symptoms and impairments (Mac Donald et al, 2016a; Yurgil et al, 2014); yet, the mechanisms underlying these impairments remain poorly understood, thereby limiting clinical management. During deployments, there is a high overlap in blast and blunt-force traumatic brain injuries (TBIs) (Chandra and Sundaramurthy, 2015; Manners et al, 2016), obscuring the physiological impact of isolated blast exposure in humans (Mac Donald et al, 2016b; MacDonald et al, 2014).…”

“…During deployments, there is a high overlap in blast and blunt-force traumatic brain injuries (TBIs) (Chandra and Sundaramurthy, 2015; Manners et al, 2016), obscuring the physiological impact of isolated blast exposure in humans (Mac Donald et al, 2016b; MacDonald et al, 2014). This is concerning, because in animal model blast-induced TBI (biTBI) has different signature features than blunt-force TBI (Courtney and Courtney, 2015).…”

Early Clinical Predictors of 5-Year Outcome After Concussive Blast Traumatic Brain Injury

“…9,10,30 In brief, participants were service members deployed to combat from November 1, 2008, through July 1, 2013, for whom original enrollment was completed directly in Afghanistan 9,29 or after medical evacuation to Landstuhl Regional Medical Center in Landstuhl, Germany. 10–12,30 Diagnosis of head injury was determined by trained medical personnel working in the TBI clinics in Germany. For the concussive blast TBI group, all available clinical histories indicated blast exposure plus another mechanism of head injury, such as a fall, motor vehicle crash, or being struck by a blunt object.…”

“…Combat-deployed controls were enrolled directly in Afghanistan or after evacuation to Germany for noncombat diagnoses such as gastrointestinal tract issues or dermatitis. Subgroup analysis by evacuation status in the control group identified no differences in any of the clinical outcome measures, 10 and the data were combined for this study.…”

“…In contrast, our group was provided the unique opportunity to examine patients in the acute 9,29 to subacute 10–12,30 stage after combat-related concussive TBI with prospective follow-up to 1-year 9–12,30 and now 5-year evaluations. This longitudinal observation has allowed for a greater appreciation of functional postinjury trajectory and the effect on long-term outcome.…”