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 deployments3. 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.

METHODSWe 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:

5. Pre-deployment: The three most severe TBIs sustained any time prior to deployment to OEF/OIF (including childhood).

6. 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.

7. Post-deployment: The three most severe TBIs sustained any time following return to states (including active duty and retired).

BACKGROUND

CONCLUSIONS

NAME OF POSTERPI 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).

Criteria Mild Moderate Severe

Loss of Consciousness

0 - 30 minutes >30 minutes and <24 hours

> 24 hours

Alteration of Mental Status

0 - 24 hours >24 hours; severity based on other criteria

Post Traumatic Amnesia

0 – 1 day > 1 day and <7 days

> 7 days

Glascow Coma Scale

13 - 15 9 - 12 <9

Criteria Grade I (must be > 0 for one of the

following)

Grade II Grade III

Loss of Consciousness

None < 5 minutes > 5 minutes

Post Traumatic Amnesia

0 - 15 minutes <24 hours but >15 minutes

>24 hours

Alteration of Mental Status

0 - 15 minutes <24 hours but >15 minutes

>24 hours

Adapted from Bailes and Cantu, 2001DOD, 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

RESULTSTable 4. Blast Exposure by Distance for Deployed (N=60) OEF/OIF Service Members (categories are not mutually exclusive)

< 10 meters 10-25 meters 25-100 meters Within 100 meters

# of People Exposed

19 23 44 48

Average # of Blasts/Person

0.7 2.9 18.4 (10.1*) 21.7 (13.4*)

Range of Blasts/Person

0-8 0-100 0-500 0-511

Severity Deployment Blast

Deployment Other

Pre-Deployment

Post Deployment

Severe # Cases 0 0 1 0Incidents 0 0 1 0

Moderate # Cases 0 0 2 0

Incidents 0 0 2 0

Mild (total) # Cases 14 10 30 5

Incidents 14 16 54 5

Stage I # Cases 8 7 17 1

Incidents 8 10 35 1

Stage II # Cases 6 5 15 3

Incidents 6 5 16 3

Stage III # Cases 0 1 3 1

Incidents 0 1 3 1

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 Rating

Table 3. Hybrid Classification System for Mild TBI

Deployment CivilianBlast All Other TBI Pre-

deploymentPost-

deployment

# of Participants

TBI Only (N=5) 1 0 4 0

TBI + Current PTSD (N=36) 10 10 17 2

TBI + Lifetime PTSD (N=40) 10 9 20 4

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)

4Moderate

TBI

5Severe

TBI

1 (Improbable TBI) 18 0 1 0 02 (Possible TBI) 2 15 2 0 03 (mTBI) 0 0 19 0 04 (Moderately Severe TBI)

0 0 0 1 0

5 (More Severe TBI) 0 0 0 1 1

*Excluding individual exposed to 500 blasts

BAT-L for Deployment TBIPositive Negative Total

VA TBI Screening Instrument

Positive 29 5 34

Negative 8 12 20

Total 37 17 54

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).