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  • Updated 04.28.2023
  • Released 11.01.1994
  • Expires For CME 04.28.2026

Chronic traumatic encephalopathy



Traumatic encephalopathy refers to a specific pathology found in the brains of people with a history of traumatic brain injury. Although first recognized as a clinical entity in the early 20th century, it has become an increasingly controversial topic in both the scientific and sporting communities over the past few decades. This article provides a look into its history and epidemiology as well as a summary of current research into the evaluation, diagnosis, and management of this neurodegenerative disease.

Key points

• Chronic traumatic encephalopathy is a neuropathological term describing abnormal protein deposits in a specific pattern in the brain; traumatic encephalopathy syndrome is the term used for the clinical presentation associated with disease.

• The clinical presentation includes a progressive form of dementia similar to, but distinct from, Alzheimer disease.

• The only known risk factor is a history of either multiple mild or at least one moderate to severe traumatic brain injury; signs and symptoms of disease often begin years or even decades after the last reported head injury.

• To date, more than 99% of cases of symptomatic former professional American football players tested were confirmed to have chronic traumatic encephalopathy at autopsy; an all-cause dementia brain bank found no evidence of the disease in cases without documented head trauma and 32% prevalence in those with history of contact sports participation.

• As with other neurodegenerative diseases, there is no cure for chronic traumatic encephalopathy, and treatment is largely symptomatic.

• Current research is underway to diagnose the clinical traumatic encephalopathy syndrome, and subsequently chronic traumatic encephalopathy, in living patients using clinical evaluation criteria and biomarkers, such as serum, cerebrospinal fluid, and imaging studies.

Historical note and terminology

Chronic traumatic encephalopathy was first described in 1928 as the clinical “punch drunk syndrome.” It was associated with people who participated in the sport of boxing, particularly those athletes who received multiple blows to the head. Pathological findings attributable to chronic traumatic encephalopathy were later published, also using former professional boxers as case studies. This entity went largely unnoticed by the general public until 2005 when the first reported case was found in a former professional American football player. Since then, chronic traumatic encephalopathy has become the focus of media attention with respect to prevention and management of brain injury in sports, particularly American football. The scientific community has likewise developed a renewed interest in the study of chronic traumatic encephalopathy, and multiple studies are currently underway to better understand this disease. The neuropathology of chronic traumatic encephalopathy has been confirmed as distinct from other forms of neurodegenerative disease, and the search continues for in vivo diagnostic and therapeutic options.

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