Merck Manual

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Chronic Traumatic Encephalopathy (CTE)

(Dementia Pugilistica)


Juebin Huang

, MD, PhD, Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center

Last full review/revision Apr 2020| Content last modified Apr 2020
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Chronic traumatic encephalopathy is a progressive degeneration of brain cells caused by several head injuries, typically in athletes but also in soldiers who have been exposed to an explosion.

Dementia pugilistica, identified in boxers in the 1920s, and chronic traumatic encephalopathy, a more recent term, are thought to be the same disorder. Chronic traumatic encephalopathy develops in some retired professional and college football players and other athletes who have had repetitive head injuries (such as concussion). It also develops in some soldiers who have had a head injury due to an explosion (blast injury) during combat.

Experts do not yet know why only certain people who have repeated head injuries develop chronic traumatic encephalopathy nor how many injuries and how much force are required to cause this disorder. About 3% of athletes who have had several (even apparently minor) concussions develop chronic traumatic encephalopathy.


At first, people with chronic traumatic encephalopathy may have one or more of the following:

  • Changes in mood: They feel depressed, irritable, and/or hopeless, sometimes leading to suicidal thoughts.

  • Changes in behavior: They act impulsively or aggressively or lose their temper easily.

  • Changes in mental function: They become forgetful, have difficulty planning and organizing, or become confused. Dementia may develop.

  • Problems with muscles: They move slowly, become uncoordinated, and/or have trouble physically producing speech (dysarthria).

People may not have any symptoms until later in life, sometimes not until their 60s. Or mood and behavior may change during young adulthood (for example, during their 30s), and mental dysfunction may occur later.


  • A doctor's evaluation

Doctors suspect chronic traumatic encephalopathy in people who

  • Have had several head injuries

  • Have symptoms typical of the disorder

  • Do not have another condition that better explains their symptoms

No tests, including imaging, can confirm the diagnosis of chronic traumatic encephalopathy.

Chronic traumatic encephalopathy can be definitively diagnosed only when a sample of brain tissue is removed after death, during an autopsy and is examined under a microscope.

Did You Know...

  • People who have had a concussion should rest and refrain from athletic and certain other activities for a period of time.


  • Safety and supportive measures

  • Counseling

  • Drugs to relieve symptoms

There is no specific treatment for chronic traumatic encephalopathy. Safety and supportive measures, as for other dementias, may help.

Safety and supportive measures

If dementia develops, creating a safe and supportive environment can be very helpful.

Generally, the environment should be bright, cheerful, safe, stable, and designed to help with orientation. Some stimulation, such as a radio or television, is helpful, but excessive stimulation should be avoided.

Structure and routine help people with dementia stay oriented and give them a sense of security and stability. Any change in surroundings, routines, or caregivers should be explained to people clearly and simply.

Following a daily routine for tasks such as bathing, eating, and sleeping helps people with dementia remember. Following a regular routine at bedtime may help them sleep better.

Activities scheduled on a regular basis can help people feel independent and needed by focusing their attention on pleasurable or useful tasks. Such activities should include physical and mental activities. Activities should be broken down in small parts or simplified as the dementia worsens.

Other measures

People with chronic traumatic encephalopathy may benefit from psychologic counseling, which may help them deal with changes in mood. Antidepressants and mood-stabilizing drugs may also help, particularly with controlling suicidal thoughts.

To help reduce risk of chronic traumatic encephalopathy, people who have had a concussion are told to rest and refrain from athletic and certain other activities for a period of time.

Care for caregivers

Caring for people with dementia is stressful and demanding, and caregivers may become depressed and exhausted, often neglecting their own mental and physical health. The following measures can help caregivers (see table Caring for Caregivers):

  • Learning about how to effectively meet the needs of people with dementia and what to expect from them: Caregivers can get this information from nurses, social workers, organizations, and published and online materials.

  • Seeking help when it is needed: Caregivers can talk to social workers (including those in the local community hospital) about appropriate sources of help, such as day-care programs, visits by home nurses, part-time or full-time housekeeping assistance, and live-in assistance. Counseling and support groups can also help.

  • Caring for self: Caregivers need to remember to take care of themselves. They should not given up their friends, hobbies, and activities.

End-of-life issues

Before people with chronic traumatic encephalopathy become too incapacitated, decisions should be made about medical care, and financial and legal arrangements should be made. These arrangements are called advance directives. People should appoint a person who is legally authorized to make treatment decisions on their behalf (a health care proxy). They should discuss their health care wishes with this person and their doctor. Such issues are best discussed with all concerned long before decisions are necessary.

As dementia worsens, treatment tends to be directed at maintaining the person’s comfort rather than at attempting to prolong life.

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
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