Mild Traumatic Brain Injury (mTBI) is the signature injury of Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) with reports of mTBI occurring in 15-22% of returning service members (Hoge et al., 2008; Terrio et al., 2009). There are additional unique factors to OEF/OIF service members that can affect the accurate characterization and consequences of mTBI: 1.Mechanism of injury (blast vs. blunt trauma) 2.Cumulative number of blast exposures and/or possible brain injuries associated with longer and more frequent deployments 3.TBIs occurring in the context of chaos and horror leading to imprecise self-report of injury and comorbid psychiatric illness (e.g., Post-traumatic Stress Disorder) 4.TBIs sustained prior to and following deployment Documentation of TBI in theater is inconsistent, non-existent, or difficult to obtain after discharge from the military. How mTBI is defined and operationalized for post-hoc classification will have significant consequences on the behavioral and neural characterization (acute & chronic) and in the determination of long-term outcome. METHODS We have developed a semi-structured clinical interview at the VA Boston Healthcare System (joint project of the Neuropsychology Service, Polytrauma Service, and TRACTS COE) to characterize and diagnose mTBI during a service member’s lifetime. Possible TBI is assessed during three lifetime epochs: 1.Pre-deployment: The three most severe TBIs sustained any time prior to deployment to OEF/OIF (including childhood). 2.Deployment: The three most severe TBI exposures (blast and all other); an estimate of the total number of blast exposures as a function of distance from the epicenter. 3.Post-deployment: The three most severe TBIs sustained any time following return to states (including active duty and retired). BACKGROUND CONCLUSIONS NAME OF POSTER PI Names, Investigator Names, Names Name of School, Name of School, Name of School Step 1: Determine the mechanism of injury, including exposure to a blast/explosion (e.g., IED, RPG, mortar) and all other blows to the head (e.g., fall, sports-related Injury, physical assault, MVA). CriteriaMildModerateSevere Loss of Consciousness minutes>30 minutes and <24 hours > 24 hours Alteration of Mental Status hours >24 hours; severity based on other criteria Post Traumatic Amnesia 0 – 1 day> 1 day and <7 days > 7 days Glascow Coma Scale <9 CriteriaGrade I (must be > 0 for one of the following) Grade IIGrade III Loss of Consciousness None< 5 minutes> 5 minutes Post Traumatic Amnesia minutes 15 minutes >24 hours Alteration of Mental Status minutes 15 minutes >24 hours Adapted from Bailes and Cantu, 2001 DOD, 2010 Step 4: The three most severe TBIs for each epoch (deployment blast, deployment other, pre-deployment, and post-deployment) are captured for data entry and reviewed at a weekly TBI diagnostic consensus meeting consisting of at least three doctoral-level Psychologists. Step 3: TBI severity is then rated according to DOD criteria and mild TBIs are graded according to a hybrid classification system. Step 2: The three primary criteria for TBI (Alteration of Mental Status, Post Traumatic Amnesia, and Loss of Consciousness) are evaluated through detailed recall of the events before, during, and after the injury. Open- ended questioning is employed to prevent response bias. Other factors that might be interpreted as alterations of consciousness (e.g., chaos and confusion due to explosions, gunfire, sensory deprivation) are queried. 1.Blast exposures are a common experience in OEF/OIF deployments, but not all result in acute TBI. Long-term consequences of multiple sub- concussive injuries are unknown. 2.Many veterans will present with histories that include multiple TBIs pre-, during and post-deployment. 3.Compared to the BAT-L, the current VA TBI Screening Instrument identified a greater number of individuals with TBI. However, eight TBI Participants: Assessment of TBI with the BAT-L RESULTS Table 4. Blast Exposure by Distance for Deployed (N=60) OEF/OIF Service Members (categories are not mutually exclusive) < 10 meters10-25 meters metersWithin 100 meters # of People Exposed Average # of Blasts/Person (10.1*)21.7 (13.4*) Range of Blasts/Person SeverityDeployment Blast Deployment Other Pre- Deployment Post Deployment Severe# Cases0010 Incidents0010 Moderate# Cases0020 Incidents0020 Mild (total)# Cases Incidents Stage I# Cases87171 Incidents Stage II# Cases65153 Incidents65163 Stage III# Cases0131 Incidents0131 Table 7. Comparison of TBI Diagnosis According Ohio State University TBI Identification Method vs. BAT-L for Deployed (N=60) OEF/OIF Service Members Table 1. Demographics for all participants (N=70) Table 5. Consensus Diagnosis of Lifetime TBI Prevalence by Severity (N=70 ) Table 2. DOD Criteria for Severity RatingTable 3. Hybrid Classification System for Mild TBI DeploymentCivilian BlastAll Other TBIPre- deployment Post- deployment # of Participants TBI Only (N=5)1040 TBI + Current PTSD (N=36) TBI + Lifetime PTSD (N=40) Table 8. TBI and PTSD in Deployed (N=60) OEF/OIF Service Members Using the BAT-L (categories are not mutually exclusive) OSU BAT-L (converted to OSU scoring) 1 (no TBI) 2 (mTBI, Stage 1) 3 (mTBI, Stages 2&3) 4 Moderate TBI 5 Severe TBI 1 (Improbable TBI) (Possible TBI) (mTBI) (Moderately Severe TBI) (More Severe TBI)00011 *Excluding individual exposed to 500 blasts BAT-L for Deployment TBI PositiveNegativeTotal VA TBI Screening Instrument Positive29534 Negative81220 Total Table 6. Identification of Possible TBI According to VA TBI Screening Instrument Compared to BAT-L for Deployed (N=54) OEF/OIF Service Members Agreement between measures was moderate (Kappa= 0.47). Agreement between measures was very good (Kappa= 0.86).