The US Military’s Definition of Mild TBI

The Department of Defense recently released a guide for primary health care providers on treating service members with traumatic brain injury (TBI). One thing I found interesting was DoD’s definition of “mild TBI”, which includes a loss of consciousness for up to 30 minutes and post traumatic amnesia for up to 24 hours.

In other words, if someone is knocked out cold for 30 minutes, and then is confused and disoriented and can’t remember much for the next 24 hours after they regain consciousness, then they have only received a mild brain injury according the Pentagon. This standard might seem a bit lax in the civilian world, but it’s also a realistic acknowledgement that US military service members operate in high risk environments for TBI.

The military and organized sports teams have taken the lead in attempting to address TBI risk through mandatory baseline cognitive assessments (to compare re-test results after a TBI event) and the newer use of portable EEG diagnostic systems. These are good first steps in a very complex problem, especially with blast related TBI, where the specific blast effects on white matter (axons) that connect different parts of the brain are still poorly understood.

The risk of re-injury is very high in these specialized groups due to their operating environments, along with a group culture that encourages members to return to the field as quickly as possible. Unfortunately, repetitive brain injuries can have devastating outcomes for some people. It’s possible we will find that personal genetics plays a role in how an individual’s brain responds to TBI – the idea that some people’s brains are simply more susceptible to long term problems from TBI. This would raise the (future) concept of screening and selection of “TBI resistant” CNS profiles for certain high risk jobs and environments.