Understanding Chronic Traumatic Encephalopathy

Rugby Union - Uruguay v Argentina - Argentina’s Joaquin Oviedo in action with Uruguay’s Manuel Diana and Andres Vilaseca REUTERS/Mariana Greif

Chronic Traumatic Encephalopathy (CTE) is a progressive neurodegenerative disease that has gained considerable attention due to its profound impact on cognitive, behavioral, and emotional health. Initially labeled as "punch-drunk syndrome" among boxers, CTE has now emerged beyond this specific demographic, affecting various populations exposed to repetitive head trauma, notably athletes in American football, hockey, rugby, soccer, and military personnel.

Etiology and Pathophysiology

Chronic Traumatic Encephalopathy is a neurodegenerative condition characterized by abnormal protein buildup, primarily tau, leading to progressive brain damage. Its association with contact sports and military service has drawn significant medical attention. It stems from repeated head trauma, resulting in cumulative brain injury and abnormal protein accumulation, particularly around blood vessels and within cortical sulci. While chronic inflammation and oxidative stress likely contribute, the precise mechanisms are still under investigation. In athletes, recurrent head impacts in contact sports like American football, hockey, rugby, soccer, and boxing are the primary cause of CTE. These repeated traumas gradually lead to brain cell deterioration and the onset of symptoms⁽¹⁾.

Epidemiology

Almost two-thirds of the American population is involved in some form of organized sport, and it is estimated that one and a half to four million concussions occur due to sports each year in the United States. It has been estimated that approximately 17% of people with a repetitive concussion or mild traumatic brain injury (TBI) develop CTE. In 2009, researchers at the Boston University School of Medicine in the USA showed that of the pathologically confirmed cases of CTE, 90% were found in athletes, 85% of those athletes were boxers, and 11% were American football players^(2,3).

Clinical Features

The clinical presentation of CTE is heterogeneous and often insidious, with symptoms typically manifesting years or even decades after the initial traumatic exposures. Common features include:

• Cognitive impairments: Memory loss, executive dysfunction, and impaired judgment.
• Behavioral changes: Aggression, impulsivity, and apathy.
• Mood disturbances: Depression, anxiety, and suicidal ideation.
• Motor symptoms: Parkinsonism, dysarthria, and gait abnormalities.

The variability in symptomatology complicates both diagnosis and management, as athletes may exhibit a wide range of symptoms depending on the extent and location of brain injury.