Dataset Information

Association Between 5-Year Clinical Outcome in Patients With Nonmedically Evacuated Mild Blast Traumatic Brain Injury and Clinical Measures Collected Within 7 Days Postinjury in Combat.

ABSTRACT:

Importance

Although previous work has examined clinical outcomes in combat-deployed veterans, questions remain regarding how symptoms evolve or resolve following mild blast traumatic brain injury (TBI) treated in theater and their association with long-term outcomes.

Objective

To characterize 5-year outcome in patients with nonmedically evacuated blast concussion compared with combat-deployed controls and understand what clinical measures collected acutely in theater are associated with 5-year outcome.

Design, setting, and participants

A prospective, longitudinal cohort study including 45 service members with mild blast TBI within 7 days of injury (mean 4 days) and 45 combat deployed nonconcussed controls was carried out. Enrollment occurred in Afghanistan at the point of injury with evaluation of 5-year outcome in the United States. The enrollment occurred from March to September 2012 with 5-year follow up completed from April 2017 to May 2018. Data analysis was completed from June to July 2018.

Exposures

Concussive blast TBI. All patients were treated in theater, and none required medical evacuation.

Main outcomes and measures

Clinical measures collected in theater included measures for concussion symptoms, posttraumatic stress disorder (PTSD) symptoms, depression symptoms, balance performance, combat exposure intensity, cognitive performance, and demographics. Five-year outcome evaluation included measures for global disability, neurobehavioral impairment, PTSD symptoms, depression symptoms, and 10 domains of cognitive function. Forward selection multivariate regression was used to determine predictors of 5-year outcome for global disability, neurobehavior impairment, PTSD, and cognitive function.

Results

Nonmedically evacuated patients with concussive blast injury (n?=?45; 44 men, mean [SD] age, 31 [5] years) fared poorly at 5-year follow-up compared with combat-deployed controls (n?=?45; 35 men; mean [SD] age, 34 [7] years) on global disability, neurobehavioral impairment, and psychiatric symptoms, whereas cognitive changes were unremarkable. Acute predictors of 5-year outcome consistently identified TBI diagnosis with contribution from acute concussion and mental health symptoms and select measures of cognitive performance depending on the model for 5-year global disability (area under the curve following bootstrap validation [AUCBV]?=?0.79), neurobehavioral impairment (correlation following bootstrap validation [RBV]?=?0.60), PTSD severity (RBV?=?0.36), or cognitive performance (RBV?=?0.34).

Conclusions and relevance

Service members with concussive blast injuries fared poorly at 5-year outcome. The results support a more focused acute screening of mental health following TBI diagnosis as strong indicators of poor long-term outcome. This extends prior work examining outcome in patients with concussive blast injury to the larger nonmedically evacuated population.

SUBMITTER: Mac Donald CL

PROVIDER: S-EPMC6324322 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Association Between 5-Year Clinical Outcome in Patients With Nonmedically Evacuated Mild Blast Traumatic Brain Injury and Clinical Measures Collected Within 7 Days Postinjury in Combat.

Mac Donald Christine L CL Barber Jason J Patterson Jana J Johnson Ann M AM Dikmen Sureyya S Fann Jesse R JR Temkin Nancy N

JAMA network open 20190104 1

<h4>Importance</h4>Although previous work has examined clinical outcomes in combat-deployed veterans, questions remain regarding how symptoms evolve or resolve following mild blast traumatic brain injury (TBI) treated in theater and their association with long-term outcomes.<h4>Objective</h4>To characterize 5-year outcome in patients with nonmedically evacuated blast concussion compared with combat-deployed controls and understand what clinical measures collected acutely in theater are associate ...[more]

PMID: 30646193

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Project description:ObjectiveTo evaluate whether diffusion tensor imaging (DTI) will noninvasively reveal white matter changes not present on conventional MRI in acute blast-related mild traumatic brain injury (mTBI) and to determine correlations with clinical measures and recovery.MethodsProspective observational study of 95 US military service members with mTBI enrolled within 7 days from injury in Afghanistan and 101 healthy controls. Assessments included Rivermead Post-Concussion Symptoms Questionnaire (RPCSQ), Post-Traumatic Stress Disorder Checklist Military (PCLM), Beck Depression Inventory (BDI), Balance Error Scoring System (BESS), Automated Neuropsychological Assessment Metrics (ANAM), conventional MRI, and DTI.ResultsSignificantly greater impairment was observed in participants with mTBI vs controls: RPCSQ (19.7 ± 12.9 vs 3.6 ± 7.1, p < 0.001), PCLM (32 ± 13.2 vs 20.9 ± 7.1, p < 0.001), BDI (7.4 ± 6.8 vs 2.5 ± 4.9, p < 0.001), and BESS (18.2 ± 8.4 vs 15.1 ± 8.3, p = 0.01). The largest effect size in ANAM performance decline was in simple reaction time (mTBI 74.5 ± 148.4 vs control -11 ± 46.6 milliseconds, p < 0.001). Fractional anisotropy was significantly reduced in mTBI compared with controls in the right superior longitudinal fasciculus (0.393 ± 0.022 vs 0.405 ± 0.023, p < 0.001). No abnormalities were detected with conventional MRI. Time to return to duty correlated with RPCSQ (r = 0.53, p < 0.001), ANAM simple reaction time decline (r = 0.49, p < 0.0001), PCLM (r = 0.47, p < 0.0001), and BDI (r = 0.36 p = 0.0005).ConclusionsSomatic, behavioral, and cognitive symptoms and performance deficits are substantially elevated in acute blast-related mTBI. Postconcussive symptoms and performance on measures of posttraumatic stress disorder, depression, and neurocognitive performance at initial presentation correlate with return-to-duty time. Although changes in fractional anisotropy are uncommon and subtle, DTI is more sensitive than conventional MRI in imaging white matter integrity in blast-related mTBI acutely.

Project description:In the military, explosive blasts are a significant cause of mild traumatic brain injuries (mTBIs). The symptoms associated with blast mTBIs causes significant economic burdens and a diminished quality of life for many service members. At present, the distinction of the injury mechanism (blast versus non-blast) may not influence TBI diagnosis. However, using noninvasive imaging, this study reveals significant distinctions between the blast and non-blast TBI mechanisms. A cortical whole-brain thickness analysis was performed using structural high-resolution T1-weighted MRI to identify the effects of blasts in persistent mTBI (pmTBI) subjects. A total of 41 blast pmTBI subjects were individually age- and gender-matched to 41 non-blast pmTBI subjects. Using FreeSurfer, cortical thickness was quantified for the blast group, relative to the non-blast group. Cortical thinning was identified within the blast mTBI group, in two clusters bilaterally. In the left hemisphere, the cluster overlapped with the lateral orbitofrontal, rostral middle frontal, medial orbitofrontal, superior frontal, rostral anterior cingulate and frontal pole cortices (p < 0.02, two-tailed, size = 1680 mm2). In the right hemisphere, the cluster overlapped with the lateral orbitofrontal, rostral middle frontal, medial orbitofrontal, pars orbitalis, pars triangularis and insula cortices (p < 0.002, two-tailed, cluster size = 2453 mm2). Self-report assessments suggest significant differences in the Post-Traumatic Stress Disorder Checklist-Civilian Version (p < 0.05, Bonferroni-corrected) and the Neurobehavioral Symptom Inventory (p < 0.01, uncorrected) between the blast and non-blast mTBI groups. These results suggest that blast may cause a unique injury pattern related to a reduction in cortical thickness within specific brain regions which could affect symptoms. No other study has found cortical thickness difference between blast and non-blast mTBI groups and further replication is needed to confirm these initial observations.

Project description:ObjectiveTo determine whether a structured and quantitative assessment of differential olfactory performance-recognized between a blast-injured traumatic brain injury (TBI) group and a demographically comparable blast-injured control group-can serve as a reliable antecedent marker for preclinical detection of intracranial neurotrauma.MethodsWe prospectively and consecutively enrolled 231 polytrauma inpatients, acutely injured from explosions during combat operations in either Afghanistan or Iraq and requiring immediate stateside evacuation and sequential admission to our tertiary care medical center over a 2½-year period. This study correlates olfactometric scores with both contemporaneous neuroimaging findings as well as the clinical diagnosis of TBI, tabulates population-specific incidence data, and investigates return of olfactory function.ResultsOlfactometric score predicted abnormal neuroimaging significantly better than chance alone (area under the curve = 0.78, 95% confidence interval [CI] 0.70-0.87). Normosmia was present in all troops with mild TBI (i.e., concussion) and all control subjects. Troops with radiographic evidence of frontal lobe injuries were 3 times more likely to have olfactory impairment than troops with injuries to other brain regions (relative risk 3.0, 95% CI 0.98-9.14). Normalization of scores occurred in all anosmic troops available for follow-up testing.ConclusionQuantitative identification olfactometry has limited sensitivity but high specificity as a marker for detecting acute structural neuropathology from trauma. When considering whether to order advanced neuroimaging, a functional disturbance with central olfactory impairment should be regarded as an important tool to inform the decision process.Classification of evidenceThis study provides Class III evidence that central olfactory dysfunction identifies patients with TBI who have intracranial radiographic abnormalities with a sensitivity of 35% (95% CI 20.6%-51.7%) and specificity of 100% (95% CI 97.7%-100.0%).

Project description:Blast-related traumatic brain injury (TBI) has been a common injury among returning troops due to the widespread use of improvised explosive devices in the Iraq and Afghanistan Wars. As most of the TBIs sustained are in the mild range, brain changes may not be detected by standard clinical imaging techniques such as CT. Furthermore, the functional significance of these types of injuries is currently being debated. However, accumulating evidence suggests that diffusion tensor imaging (DTI) is sensitive to subtle white matter abnormalities and may be especially useful in detecting mild TBI (mTBI). The primary aim of this study was to use DTI to characterize the nature of white matter abnormalities following blast-related mTBI, and in particular, examine the extent to which mTBI-related white matter abnormalities are region-specific or spatially heterogeneous. In addition, we examined whether mTBI with loss of consciousness (LOC) was associated with more extensive white matter abnormality than mTBI without LOC, as well as the potential moderating effect of number of blast exposures. A second aim was to examine the relationship between white matter integrity and neurocognitive function. Finally, a third aim was to examine the contribution of PTSD symptom severity to observed white matter alterations. One hundred fourteen OEF/OIF veterans underwent DTI and neuropsychological examination and were divided into three groups including a control group, blast-related mTBI without LOC (mTBI - LOC) group, and blast-related mTBI with LOC (mTBI + LOC) group. Hierarchical regression models were used to examine the extent to which mTBI and PTSD predicted white matter abnormalities using two approaches: 1) a region-specific analysis and 2) a measure of spatial heterogeneity. Neurocognitive composite scores were calculated for executive functions, attention, memory, and psychomotor speed. Results showed that blast-related mTBI + LOC was associated with greater odds of having spatially heterogeneous white matter abnormalities. Region-specific reduction in fractional anisotropy (FA) in the left retrolenticular part of the internal capsule was observed in the mTBI + LOC group as the number of blast exposures increased. A mediation analysis revealed that mTBI + LOC indirectly influenced verbal memory performance through its effect on white matter integrity. PTSD was not associated with spatially heterogeneous white matter abnormalities. However, there was a suggestion that at higher levels of PTSD symptom severity, LOC was associated with reduced FA in the left retrolenticular part of the internal capsule. These results support postmortem reports of diffuse axonal injury following mTBI and suggest that injuries with LOC involvement may be particularly detrimental to white matter integrity. Furthermore, these results suggest that LOC-associated white matter abnormalities in turn influence neurocognitive function.

Dataset Information

Association Between 5-Year Clinical Outcome in Patients With Nonmedically Evacuated Mild Blast Traumatic Brain Injury and Clinical Measures Collected Within 7 Days Postinjury in Combat.

Importance

Objective

Design, setting, and participants

Exposures

Main outcomes and measures

Results

Conclusions and relevance

Publications

Association Between 5-Year Clinical Outcome in Patients With Nonmedically Evacuated Mild Blast Traumatic Brain Injury and Clinical Measures Collected Within 7 Days Postinjury in Combat.

Similar Datasets

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