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Chronic Traumatic Encephalopathy

Author: Judy Zhu


Chronic traumatic encephalopathy (CTE) is used to describe brain degeneration likely caused by repeated head traumas. It is a very rare disorder that is not yet well understood. It is thought to cause areas of the brain to experience atrophy (shrink away). CTE was previously known as "punch drunk" syndrome and dementia pugilistica. However, these terms are no longer used because it is now known that the condition is not limited to ex-boxers.


CTE symptoms do not develop right after a brain injury, but experts believe that they might develop over years or decades after repeated brain trauma. Little is known right now about how CTE progresses, and it is unclear what kind of symptoms, if any, CTE may cause.


However, in the few people with proven CTE, symptoms have included:

  • Difficulty thinking

  • Impulsive behavior

  • Depression or apathy

  • Short-term memory loss

  • Difficulty planning and carrying out tasks

  • Emotional instability

  • Substance misuse

  • Suicidal thoughts or behavior


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.


A 2020 study from the VA-BU-CLF Brain Bank suggested that problems with sleep, specifically symptoms associated with rapid eye movement (REM) behavior disorder, may also be related to CTE.



Repetitive brain trauma is likely the cause of CTE. Most of the studies have been centered around the brains of people who played contact sports, including football, ice hockey, and boxing, as well as in military personnel who were exposed to explosive blasts, though other factors such as physical abuse can also lead to repeated brain injuries.


The best available evidence points out that sub-concussive impacts (hits to the head that do not cause full-blown concussions) as the biggest factor of CTE.


Currently, CTE can only be diagnosed after death through brain tissue analysis. Doctors slice brain tissue and use special chemicals to make the abnormal tau protein visible and systematically search areas of the brain for tau in the unique pattern specific to CTE.


The process can take several months to complete, and the analysis is not typically performed as a part of a normal autopsy. In fact, until recently there were relatively few doctors who knew how to diagnose CTE.


There is no treatment for CTE. However, CTE may be prevented by avoiding repetitive head injuries.


For example:

  • wear the recommended protective equipment during contact sports

  • follow the doctor's recommendations about returning to play after a concussion

  • being supervised by a properly qualified and trained person when playing contact sports

  • get medical advice if any symptoms of a previous head injury return



“Chronic Traumatic Encephalopathy - Symptoms and Causes.” Mayo Clinic, 4 June 2019,,is%20not%20yet%20well%20understood.Kasiaheith.

NHS website. “Chronic Traumatic Encephalopathy.” Nhs.Uk, 30 Apr. 2019,

What Is CTE? | Concussion Legacy Foundation.” Concussion Legacy Foundation, Accessed 13 May 2021.


“Pin by Gloria A. on Brain | Cerebral Atrophy, Brain Diseases, Brain.” Pinterest, Accessed 13 May 2021.

Boston University Center for the Study of Traumatic Encephalopathy -

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