TBI

Overview

Traumatic Brain Injury (TBI) is a significant health issue which affects service members and veterans during times of both peace and war. The high rate of TBI and blast-related concussion events resulting from current combat operations directly impacts the health and safety of individual service members and subsequently the level of unit readiness and troop retention. The impacts of TBI are felt within each branch of the service and throughout both the Department of Defense (DoD) and the Department of Veterans Affairs (VA) health care systems.

In the VA, TBI has become a major focus, second only to recognition of the need for increased resources to provide health care and vocational retraining for individuals with a diagnosis of TBI, as they transition to veteran status. Veterans may sustain TBIs throughout their lifespan, with the largest increase as the veterans enter into their 70s and 80s; these injuries are often caused by falls and result in high levels of disability.

Active duty and reserve service members are at increased risk for sustaining a TBI compared to their civilian peers. This is a result of several factors, including the specific demographics of the military; in general, young men between the ages of 18 to 24 are at greatest risk for TBI. Many operational and training activities, which are routine in the military, are physically demanding and even potentially dangerous. Military service members are increasingly deployed to areas where they are at risk for experiencing blast exposures from improvised explosive devices (IEDs), suicide bombers, land mines, mortar rounds, and rocket-propelled grenades. These and other combat related activities put our military service members at increased risk for sustaining a TBI.

What is a TBI?

  • A Traumatic Brain Injury (TBI) can be classified as mild, moderate, severe or penetrating, the severity is determined at the time of injury
  • A TBI is a blow or jolt to the head that disrupts the normal function of the brain. It may knock you out briefly or for an extended period of time, or make you feel confused or “see stars” (alteration of consciousness)
  • Not all blows or jolts to the head result in a TBI
  • The most common form of TBI in the military is mild (concussion is another word for a mild TBI)

What are the causes?

In the military, the leading causes of TBI both deployed and non-deployed are (in no particular order):

  • Blasts
  • Bullets
  • Fragments
  • Falls
  • Motor vehicle – crashes and rollovers
  • Sports
  • Assaults

Who is at greatest risk for TBI?

Those who are at a higher risk for sustaining TBIs are young men who are performing military duties, or have a history of prior concussion and/or substance abuse.

BLAST INJURIES

How do explosive blasts cause a TBI?

  • Blasts from various forms of improvised explosive devices (IEDs) are a common cause of combat-related injury in the military and were the most common cause of combat-related concussions during Operation Enduring Freedom and Operation Iraqi Freedom
  • There are four different mechanisms through which a blast can cause injury:
    • Primary injury: Atmospheric over-pressure followed by under-pressure or vacuum
    • Secondary injury: Objects placed in motion (shrapnel) by the blast hitting the service member
    • Tertiary injury: Service member being thrown by the blast and hitting their head against the ground, a wall, or other solid surface
    • Quaternary injury: Other injuries from the blast such as burns and crush injuries
  • For passengers in vehicles hit by a blast, such as an IED, it’s common to sustain both a primary and tertiary injury

Does a blast cause different brain injuries than blunt trauma?

  • There currently is no evidence to suggest significant differences between blast and blunt injury (SOURCE : Defense and Veterans Brain Injury Center)
  • MRI imaging studies, such as diffusion tensor imaging, don’t indicate microstructural differences
  • No cognitive differences have been identified between blunt and blast induced concussions

How should TBI from a blast injury be treated?

  • Since most evidence suggests that blast and blunt TBI are very similar, there’s no difference in the treatment
  • All service members who sustain a concussion following a blast are thought to have injury not only from the blast, but also from blunt trauma