Chronic traumatic encephalopathy


Chronic traumatic encephalopathy is a type of brain disease that is likely caused by repeated head trauma. It is diagnosed only during the autopsy by studying the brain.

The disease of chronic traumatized encephalopathy (CTE) is not well understood. It is not related to the immediate consequences of a late episode of head trauma. 

Researchers are still investigating how repeated head injuries, including the number of head injuries and the severity of those injuries, and other factors contribute to changes in the brain that lead to CTE.

People who played football and other contact sports, including boxing, have been observed to have chronic traumatic encephalopathy. It can also occur in military personnel who have been exposed to explosions. 

CTE is thought to include impaired cognition and emotion, physical problems, and other behaviors. These are thought to develop years to decades after a head injury.

Except in the few people at high risk, chronic traumatic encephalopathy cannot be diagnosed throughout life. Researchers do not yet know its frequency in the population and do not understand the causes. There is currently no cure. 

Symptoms of chronic traumatic encephalopathy

No specific symptoms have been clearly linked to chronic traumatic encephalopathy. Some possible signs and symptoms can occur in many other conditions. There were cognitive, behavioral, mood, and motor changes in the few people diagnosed with encephalopathy.

Cognitive deficit

  • Difficulty thinking (cognitive disorders)
  • Memory loss
  • Problems planning, organizing and performing tasks (executive function)

Behavioral changes

  • Impulsive behavior
  • Assault

Mood disorders

  • Depression or apathy
  • emotional instability
  • Substance abuse
  • Suicidal thoughts or behaviors

Motor symptoms

  • Parkinsonism
  • Motor neuron disease

Researchers believe that symptoms can develop over years or decades after repeated head trauma, even though they don’t develop immediately. Symptoms of encephalopathy appear in two forms. Early in life, between the late 20s and early 30s, the first form of can cause mental health and behavioral problems, including depression, anxiety, impulsiveness, and aggression. The second form is thought to cause symptoms later in life, around age 60. These symptoms include memory and thinking problems that can progress to dementia.

Causes of chronic traumatic encephalopathy

Repetitive head trauma is likely the cause of CTE. Football and ice hockey players or boxers, as well as military personnel serving in war zones, have been the focus of most studies.

However, not all athletes and those who experience repeated concussions, including military personnel, develop chronic traumatic encephalopathy. Some studies have shown no increased incidence of encephalopathy in people exposed to repeated head trauma.Some studies question the hypothesis of a link between chronic traumatic encephalopathy and repeated head trauma.

The media have widely reported that chronic traumatic encephalopathy is a neurodegenerative disease often affecting retired athletes who have practiced contact sports (American football or boxing, for example). 

An epidemiological study casts doubt on this observation. The previous results of this association would be due to the fact that these athletes have a longer life expectancy and therefore an increased risk of Alzheimer’s disease. Source: Hippocampal Sclerosis in Dementia, Epilepsy, and Ischemic Injury. Journal of Neuropathology & Experimental Neurology, 2014; 73 (2): 136.

In the brains of sufferers, the researchers discovered that there was an accumulation of a protein called tau around the blood vessels. Chronic traumatized encephalopathy is thought to cause certain areas of the brain to atrophy.

People with CTE may show signs of another neurodegenerative disease, including Alzheimer’s disease, amyotrophic lateral sclerosis (ALS) – also known as Lou Gehrig’s disease – Parkinson’s disease or frontotemporal dementia.

Risk factors

Repeated exposure to traumatic brain injury is thought to increase the risk of CTE.


There is no cure for chronic traumatized encephalopathy, but the current recommendation is to reduce mild traumatic brain injury and prevent further injury after a concussion.

Diagnosis of chronic traumatic encephalopathy

There is currently no way to diagnose CTE. It can only be suspected in people at high risk due to repeated head trauma over the years. A diagnosis requires evidence of brain tissue degeneration and deposits of tau and other proteins in the brain that can only be seen at autopsy.


A positron emission tomography (PET) scan uses a radioactive tracer that is injected into a vein. Then, a scanner tracks the flow of the tracer through the brain and targets the buildup of tau.