title: Prospectively assessed clinical outcomes in concussive blast vs nonblast traumatic brain injury among evacuated US military personnel.
abstract: OBJECTIVE
  Blast injury has been identified as the signature injury in the conflicts in Iraq and Afghanistan. However it remains to be determined whether fundamental differences may exist between blast-related traumatic brain injury (TBI) and TBI due to other mechanisms.
  
  
  OBJECTIVE
  To determine similarities and differences between clinical outcomes in US military personnel with blast-related vs. non-blast-related concussive TBI and to identify the specific domains of impairment that best correlate with overall disability.
  
  
  METHODS
  Prospective cohort study involving active duty US Military personnel evacuated from Iraq or Afghanistan to Landstuhl Regional Medical Center, in Landstuhl, Germany. Four groups of participants were enrolled from 2010 to 2013: (1) blast plus impact complex TBI (n=53), (2) non-blast related TBI with injury due to other mechanisms (n=29), (3) blast-exposed controls evacuated for other medical reasons (n=27) (4) non-blast-exposed controls evacuated for other medical reasons (n=69). All patients with TBI met Department of Defense criteria for concussive (mild) TBI. The study participants were evaluated 6-12 months after injury at Washington University in St Louis. In total, 255 subjects were enrolled in the study, and 183 participated in follow-up evaluations, 5 of whom were disqualified.
  
  
  METHODS
  In-person clinical examinations included evaluation for overall disability, a standardized neurological exam, headache questionnaires, neuropsychological test battery, combat exposure and alcohol use surveys, and structured interview evaluations for post-traumatic stress disorder (PTSD) and depression.
  
  
  RESULTS
  Global outcomes, headache severity, neuropsychological performance, and surprisingly even PTSD severity and depression were indistinguishable between the two TBI groups, independent of mechanism of injury. Both TBI groups had higher rates of moderate to severe overall disability than the respective control groups: 41/53 (77%) of blast plus impact TBI and 23/29 (79%) of nonblast TBI vs. 16/27 (59%) of blast-exposed controls and 28/69 (41%) of non-blast-exposed controls. In addition, blast-exposed controls had worse headaches and more severe PTSD than non-blast-exposed controls. Self-reported combat exposure intensity was higher in the blast plus impact TBI group than in nonblast TBI group and was higher in blast-exposed controls than in non-blast-exposed controls. However, combat exposure intensity did not correlate with PTSD severity in the TBI groups, but a modest positive correlation was observed in the controls. Overall outcomes were most strongly correlated with depression, headache severity, and number of abnormalities on neuropsychological testing. However a substantial fraction of the variance in overall outcome was not explained by any of the assessed measures.
  
  
  CONCLUSIONS
  One potential interpretation of these results is that TBI itself, independent of injury mechanism and combat exposure intensity, is a primary driver of adverse outcomes. Many other important factors may be as yet unmeasured, and adverse outcomes following war-time injuries are difficult to fully explain.
  
  
  BACKGROUND
  clinicaltrials.gov Identifier: NCT01313130.
authors.affiliation: Department of Neurology, Washington University School of Medicine, St Louis, Missouri2Department of Neurological Surgery, University of Washington, Seattle.
authors.forename: Christine L
authors.initials: CL
authors.lastname: Mac Donald
authors.affiliation: Department of Neurology, Washington University School of Medicine, St Louis, Missouri.
authors.forename: Ann M
authors.initials: AM
authors.lastname: Johnson
authors.affiliation: Landstuhl Regional Medical Center, Landstuhl, Germany.
authors.forename: Linda
authors.initials: L
authors.lastname: Wierzechowski
authors.affiliation: Landstuhl Regional Medical Center, Landstuhl, Germany.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Kassner
authors.affiliation: Landstuhl Regional Medical Center, Landstuhl, Germany.
authors.forename: Theresa
authors.initials: T
authors.lastname: Stewart
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St Louis, Missouri.
authors.forename: Elliot C
authors.initials: EC
authors.lastname: Nelson
authors.affiliation: Department of Neurology, Washington University School of Medicine, St Louis, Missouri.
authors.forename: Nicole J
authors.initials: NJ
authors.lastname: Werner
authors.affiliation: Landstuhl Regional Medical Center, Landstuhl, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Zonies
authors.affiliation: Landstuhl Regional Medical Center, Landstuhl, Germany5Department of Trauma, Critical Care, and Acute Care Surgery, Walter Reed National Military Medical Center, Baltimore, Maryland.
authors.forename: John
authors.initials: J
authors.lastname: Oh
authors.affiliation: Landstuhl Regional Medical Center, Landstuhl, Germany6US Air Force Center for Sustainment of Trauma and Readiness Skills, R. Adams Cowley Shock Trauma Center, University of Maryland, Baltimore.
authors.forename: Raymond
authors.initials: R
authors.lastname: Fang
authors.affiliation: Department of Neurology, Washington University School of Medicine, St Louis, Missouri.
authors.forename: David L
authors.initials: DL
authors.lastname: Brody
mesh_terms: D000328:Adult; D055826:Afghan Campaign 2001-; D001753:Blast Injuries / Q000150:complications / Q000209:etiology / Q000503:physiopathology*; D001924:Brain Concussion / Q000209:etiology / Q000503:physiopathology; D001930:Brain Injuries / Q000150:complications / Q000209:etiology / Q000503:physiopathology*; D003863:Depression / Q000209:etiology / Q000503:physiopathology; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D023261:Glasgow Outcome Scale; D006261:Headache / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D054542:Iraq War, 2003-2011; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D009483:Neuropsychological Tests; D012720:Severity of Illness Index; D013313:Stress Disorders, Post-Traumatic / Q000209:etiology / Q000503:physiopathology; D014481:United States; D055815:Young Adult