Traumatic brain injury (TBI) is among the earliest illnesses described in human history and remains a major source of morbidity and mortality in the modern era. More than 2% of Americans currently lives with long-term disabilities as a result of a previous brain injury, and incidence and prevalence rates are even higher.

One of the most common and devastating consequences of suffering from a brain injury is dementia. Studies have shown that suffering from a TBI early on in life, is associated with an increased risk of dementia later on in life.

Studies show that moderate and severe brain injuries increase the risk of dementia between 2- and 4-fold. It’s not as clear if mild traumatic brain injuries, like concussions, leads to dementia, mainly due to the fact that mild TBIs are often not well documented. However, studies have also shown that that multiple mild brain injuries, such as those sustained by professional boxers and football players, are associated with a high risk of chronic traumatic encephalopathy (CTE), a type of dementia with distinctive clinical and pathologic features.

The recent recognition that CTE is common in retired professional athletes, such as boxers, ice hockey and football players, has increased interest in this condition. Additionally, military personnel also experience extremely high rates of brain injuries due to combat blasts. These injuries may have a similar syndrome and long-term effect.

It is presently unknown whether dementia in TBI survivors is pathophysiologically similar to Alzheimer disease, CTE, or some other form of long-term brain damage. Such information is critical for developing preventive and treatment strategies for a common cause of acquired dementia.