Functional status after blast-plus-impact complex concussive traumatic brain injury in evacuated United States military personnel

Abstract

Fundamental questions remain unanswered about the longitudinal impact of blast-plus-impact complex traumatic brain injuries (TBI) from wars in Iraq and Afghanistan. This prospective, observational study investigated measures of clinical outcome in US military personnel evacuated to Landstuhl Regional Medical Center (LRMC) in Germany after such "blast-plus" concussive TBIs. Glasgow Outcome Scale-Extended assessments completed 6-12 months after injury indicated a moderate overall disability in 41/47 (87%) blast-plus TBI subjects and a substantial but smaller number (11/18, 61%, p=0.018) of demographically similar US military controls without TBI evacuated for other medical reasons. Cognitive function assessed with a neuropsychological test battery was not different between blast-plus TBI subjects and controls; performance of both groups was generally in the normal range. No subject was found to have focal neurological deficits. However, 29/47 (57%) of blast-plus subjects with TBI met all criteria for post-traumatic stress disorder (PTSD) versus 5/18 (28%) of controls (p=0.014). PTSD was highly associated with overall disability; 31/34 patients with PTSD versus 19/31 patients who did not meet full PTSD criteria had moderate to severe disability (p=0.0003). Symptoms of depression were also more severe in the TBI group (p=0.05), and highly correlated with PTSD severity (r=0.86, p<0.0001). Thus, in summary, high rates of PTSD and depression but not cognitive impairment or focal neurological deficits were observed 6-12 months after concussive blast-plus-impact complex TBI. Overall disability was substantially greater than typically reported in civilian non-blast concussive ("mild") patients with TBI, even with polytrauma. The relationship between these clinical outcomes and specific blast-related aspects of brain injuries versus other combat-related factors remains unknown.

Figures

FIG. 1.

Screening, enrollment, and exclusion characteristics of the study participants. TBI, tramautic brain injury; MRI, magnetic resonance imaging.

FIG. 2.

Clinical assessments in US military personnel with concussive “blast-plus” traumatic brain injury (TBI). (A) Military Acute Concussion Evaluation (MACE) scores in subjects with TBI 1–90 days after injury at Landstuhl Regional Medical Center. Maximum score is 30. Higher scores indicate better performance. A cutoff of below 25 (blue dashed line) is considered to represent poor performance. (B) Global clinical outcomes assessed using the Glasgow Outcome Scale-Extended (GOS-E) scores 6–12 months after enrollment. *Indicates one-tailed Mann-Whitney U test. (C) Post-traumatic stress disorder (PTSD) severity, based on the Clinician Administered PTSD scale (CAPS). Higher scores represent more severe PTSD; maximum score is 132. **Indicates two-sided Student t test. (D) Depression severity assessed based on the Montgomery-Asberg Depression Rating Scale (MADRS) structured interview. Dashed blue line indicated cutoff score of 19: >19 reflects moderate to severe depression. *Indicates one-sided Mann-Whitney U test. Color image is available online at www.liebertpub.com/neu

FIG. 3.

Post-traumatic stress disorder (PTSD) severity assessed using Clinician Administered PTSD scale (CAPS subscales A–C). Subjects with traumatic brain injury (TBI) had more severe PTSD symptoms in all three sub-domains. The sub-domains were based on the DSM-IV criteria for PTSD. The maximum scores are CAPS B: 40, CAPS C: 56, CAPS D: 40. Bars represent mean and standard deviation. **Indicates one-sided Student t tests <0.017 after Bonferroni correction for multiple comparisons. Inverse correlation between self-reported years of formal education and PSTD severity (D). Color image is available online at www.liebertpub.com/neu

FIG 4.

Correlations between self-reported sleep deprivation and test performance. (A) Positive correlation with Neurobehavioral Rating Scale total score, where higher scores indicate worse performance. (B) Negative correlation with visual memory performance on the delayed recall portion of the Rey-Osterrieth Complex Figure Test, where lower Z-scores indicate worse performance. (C) Negative correlation with verbal memory performance on the long delay free recall portion of the California Verbal Learning Test, where again lower Z-scores indicate worse performance. (D) Negative correlation with sustained vigilance, assessed using the hit rate block change measure from the Conners Continuous Performance Test, where similarly lower Z-scores indicate worse performance. TBI, traumatic brain injury. Color image is available online at www.liebertpub.com/neu