Chronic traumatic encephalopathy

Jason L Weller MD (

Dr. Weller of the Boston VA Healthcare System and Boston University School of Medicine has no relevant financial relationships to disclose.

Katherine Turk MD (

Dr. Turk of the Boston VA Healthcare System and Boston University School of Medicine has no relevant financial relationships to disclose

Andrew E Budson MD (

Dr. Budson of the Boston VA Healthcare System and Boston University School of Medicine has no relevant financial relationships to disclose.

Howard S Kirshner MD, editor. (Dr. Kirshner of Vanderbilt University School of Medicine has no relevant financial relationships to disclose.)
Originally released November 1, 1994; last updated February 4, 2020; expires February 4, 2023

This article includes discussion of chronic traumatic encephalopathy, CTE, dementia pugilistica, punch drunk syndrome, posttraumatic dementia, and traumatic encephalopathy syndrome. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.


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 a hotly-debated topic in both the scientific and sporting communities over the past decade. 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 1 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 have confirmed 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 geared toward management of symptoms.


• 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 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.

The content you are trying to view is available only to logged in, current MedLink Neurology subscribers.

If you are a subscriber, please log in.

If you are a former subscriber or have registered before, please log in first and then click select a Service Plan or contact Subscriber Services. Site license users, click the Site License Acces link on the Homepage at an authorized computer.

If you have never registered before, click Learn More about MedLink Neurology  or view available Service Plans.

Find out how you can join MedLink Neurology