In the recent wars in Iraq and Afghanistan, US military personnel have suffered over 333,000 traumatic brain injuries (TBIs), with over 85% being mild TBI. A variety of improvised munitions, such as improvised explosive devices (IEDs) and improvised rocket assisted mortars (IRAMs), have resulted in the explosive blast-induced TBI (bTBI). Due to its prevalence, TBI has been referred to as the signature wound of US warfighters in Afghanistan and Iraq. Explosive blast produces damage to the brain by creating a dynamic environment in forms of overpressure shock wave, heat impulse, blast-propelled projectiles, and debris, whose impact can cause complex injuries in the brain and other visceral organ systems, such as lung and bowel. Mechanisms of bTBI incorporate all forms of TBI such as falls, motor vehicle accidents, and coup-contrecoup injury. Some of the unique aspects of bTBI include the rate at which the injury occurs, the differential pressure load on and within the tissue, and the pressure-loaded tissue response. Mild bTBI is the most problematic injury within the US military in terms of number of warfighters affected and recognition of the injury. The pathobiology of mild bTBI is not fully understood. Here, we review mild bTBI injury, symptomology, and diagnosis. Finally, multi-modality testing is discussed, including functional, structural, and evidence-based evaluation with an intention to describe and diagnose mild bTBI affecting the US warfighter.
Part of the book: Traumatic Brain Injury