Traumatic Brain Injury

What Is Traumatic Brain Injury (TBI)?

TBIs result from a bump, blow, or jolt to the head, or from a penetrating head injury. Explosive blasts can also cause TBIs; this is a particular concern among those who serve in the military. Essentially, any external force that causes the brain to move within the head can disrupt normal brain function, leading to loss of consciousness, or being dazed and confused.

Clinical Signs of Alteration in Brain Function3

  • Any period of loss of or decreased consciousness
  • Any loss of memory for events immediately before or after the injury
  • Neurologic deficits such as muscle weakness, loss of balance and coordination, disruption of vision, change in speech and language, or sensory loss
  • Any alteration in mental state at the time of the injury such as confusion, disorientation, slowed thinking, or difficulty with concentration

TBI in Veterans: a Population of Special Concern3

Military service members and veterans of recent conflicts and combat are a population of special concern.

Since September 11, 2001, the U.S. has deployed more than 2.7 million men and women to support combat operations in Iraq and Afghanistan.9

According to the Department of Defense’s evaluation of U.S. military casualty statistics:

  • From 2000-2019 Q3, 413,858 United States military personnel worldwide experienced a TBI; 82.8% were considered mild, 9.8% moderate, and 2.3% penetrating or severe.15
  • The incidence of TBI has increased since 2000, with a peak in 2011 and 2012.8
  • Approximately 80% of new TBI cases occur in non-deployed settings, with military members also sustaining TBIs during training activities.3
  • Out of 770,000 veterans of Operations Enduring Freedom and Iraqi Freedom who sought care from a VA Medical Center, nearly 60,000 were evaluated or treated for a TBI-related condition.10

Further, military personnel with a history of mild TBI are at an increased risk for developing post-traumatic stress (PTS).3,11

Among U.S. Army infantry soldiers returning from Iraq, 43.9% of those who reported a TBI with loss of consciousness also reported symptoms of PTS.

TBI is a Leading Cause of Death and Disability in the United States12

In 2014, TBIs accounted for approximately 2.5 million emergency department visits, hospitalizations, and deaths in the US.3

Of these, approximately:

  • 86% (2.2 million) patients were treated and released from emergency departments
  • 12% (288,000) were hospitalized and discharged alive
  • Over 2% (56,000) died

TBI facts - Traumatic Brain Injury facts

However, these numbers grossly underestimate the true occurrence of TBI: they do not include those who received no care, or received care at another type of medical facility.

TBI is involved in nearly half of all trauma deaths and one-third of all injury-related deaths. Every day, 153 people in the US die from injuries that include TBI.3,4


TBI Disrupts Normal Functioning of the Brain, and Has a Broad Spectrum of Symptoms and Disabilities3,5

Symptoms: Cognitive impairment is the hallmark of TBI; however, physical, sensory, and cognitive symptoms emerge in even mild TBI, and are progressively worse in moderate-to-severe injury. 14

  • Mild TBI
    • The majority of TBI survivors (75%) have mild brain injury that involves a brief change in mental status or consciousness, with no structural damage to the brain observed.
    • Symptoms may be subtle, ranging from no apparent deficit (full recovery) to temporary personality changes; however, individuals may experience lifelong cognitive or psychological challenges.
  • Severe TBI
    • For severe TBI, an extended period of unconsciousness or amnesia typically occurs after the injury, with measurable brain damage as observed by brain imaging.
    • Patients require acute and intensive medical intervention to survive, and can face a long road of recovery with potential lifelong disability.

TBIs can lead to a spectrum of secondary conditions that might result in long-term impairment, functional limitation, disability, and reduced quality of life.2


Unmet Needs Exist in the Diagnosis and Treatment of TBI

Diagnosis: Classification of TBI based on patterns and types of injury is important to ensure proper treatment and long-term therapy. However, the complexity of TBI and limitations of available assessment tools make this challenging.3

Treatment: Many stakeholders are involved in the continuum of care for moderate to severe TBI.5

  • Treaters include emergency department care, trauma specialty units, outpatient or community services, and continued treatment at rehabilitation centers.
  • However, at least two-thirds of patients discharged from TBI rehabilitation hospitals after a typical stay of 16 days get no further treatment.13

More effective diagnostic, rehabilitation, and treatment strategies are needed to mitigate the negative health impact of TBI.

Moving forward, various types of predictive and diagnostic tests have been envisioned for TBI to better assess premorbid risk factors, provide prognostic indicators at the TBI event, and predict treatment response and disease progression.


  1. Koponen S, Taiminen T, Portin R, et al. Axis I and II psychiatric disorders after traumatic brain injury: a 30-year follow-up study. Am J Psychiatry. 2002;159:1315-1321.
  2. Brain Inury Association of America (BIAA). Fact sheets: quick facts about brain injury and the BIAA. 2015.
  3. Centers for Disease Control and Prevention. Report to Congress. Traumatic brain injury in the United States: epidemiology and rehabilitation. Atlanta, GA: National Center for Injury Prevention and Control; Division of Unintentional Injury Prevention; 2014.
  4. Faul M, Xu L, Wald MM, Coronado VG. Traumatic brain injury in the United States: emergency department visits, hospitalizations, and deaths. Atlanta, GA: Centers for Disease Control and Prevention, National Center for Injury Prevention and Control; 2010.
  5. Mayo Clinic. Traumatic brain injury. 2014.
  6. Hook G, Jacobsen JS, Grabstein K, Kindy M, Hook V. Cathepsin B is a new drug target for traumatic brain injury therapeutics: evidence for E64d as a promising lead drug candidate. Front Neurol. 2015;6:178.
  7. Loane DJ, Faden AI. Neuroprotection for traumatic brain injury: translational challenges and emerging therapeutic strategies. Trends Pharmacol Sci. 2010;31:596-604.
  8. Congressional Research Service. A guide to U.S. military casualty statistics: Operation Freedom’s Sentinel, Operation Inherent Resolve, Operation New Dawn, Operation Iraqi Freedom, and Operation Enduring Freedom. August 7, 2015.,
  9. Ramchand R, Rudavsky R, Grant S, Tanielian T, Jaycox L. Prevalence of, risk factors for, and consequences of posttraumatic stress disorder and other mental health problems in military populations deployed to Iraq and Afghanistan. Curr Psychiatry Rep. 2015;17:37.
  10. RAND Center for Military Health Policy Research. Invisible wounds of war: psychological and cognitive injuries, their consequences, and services to assist recovery. Santa Monica, CA: RAND Corporation; 2008.
  11. Bryant RA, Friedman MJ, Spiegel D, Ursano R, Strain J. A review of acute stress disorder in DSM-5. Depress Anxiety. 2011;28:802-817.
  12. Coronado VG, Xu L, Basavaraju SV, et al. Surveillance for traumatic brain injury-related deaths–United States, 1997-2007. MMWR Surveill Summ. 2011;60:1-32.
  13. Sternberg S. For brain injuries, a treatment gap. USA Today. March 3, 2011.
  14. Taylor CA, Bell JM, Breiding MJ, Xu L. Traumatic Brain Injury–Related Emergency Department Visits, Hospitalizations, and Deaths — United States, 2007 and 2013. MMWR Surveill Summ 2017;66(No. SS-9):1–16. Accessed at:
  15. U.S. Department of Defense Numbers for Traumatic Brain Injury Worldwide – DoD Numbers for Traumatic Brain Injury Worldwide