- Chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative disease associated with repeated head injuries, including concussions and subconcussive blows. It has been most notably observed in contact sport athletes (such as football players, boxers, and hockey players), military veterans exposed to blast injuries, and others with a history of repetitive brain trauma. CTE typically develops over years or even decades after the injuries occur.
- The core pathology of CTE is the abnormal accumulation of hyperphosphorylated tau protein in specific patterns within the brain. Unlike Alzheimer’s disease, in which tau tangles are mostly found deep within the brain’s cortex and hippocampus, CTE is characterized by tau deposits around small blood vessels (perivascular) and at the depths of the cortical sulci. Over time, this tau pathology spreads and contributes to widespread neuronal loss, gliosis, and brain atrophy—particularly in the frontal and temporal lobes.
- Clinically, CTE is associated with a range of cognitive, behavioral, mood, and motor symptoms. The disease often begins with subtle changes in mood and behavior, including irritability, depression, impulsivity, aggression, and emotional instability. As it progresses, patients may develop memory problems, executive dysfunction, and dementia. In some cases, motor symptoms resembling Parkinson’s disease, such as tremor, bradykinesia, and gait instability, may also occur. The clinical course of CTE is variable and not all individuals with a history of head trauma will develop the condition.
- CTE can currently only be definitively diagnosed post-mortem through neuropathological examination of the brain. Researchers analyze brain tissue for the distinctive tau pathology and the pattern of neurodegeneration. Ongoing studies are working toward the development of biomarkers—including imaging and fluid-based tests—that might allow for diagnosis during life, but no validated clinical diagnostic test yet exists.
- Because CTE is caused by repeated brain trauma, the primary focus for prevention is reducing exposure to such injuries. This includes implementing safety measures in sports, improving helmet design, enforcing rules to prevent head hits, and ensuring proper management of concussions. In military settings, efforts focus on mitigating blast exposure and providing early care after head injuries.
- There is no cure or disease-specific treatment for CTE. Management currently focuses on addressing individual symptoms—such as depression, anxiety, cognitive difficulties, or movement problems—and supporting overall quality of life. Multidisciplinary care involving neurologists, psychiatrists, therapists, and family support is often necessary.
- CTE has gained increasing public attention due to high-profile cases among professional athletes and growing concern over sports-related brain injuries. Ongoing research aims to clarify the mechanisms behind CTE, identify individuals at risk, and develop tools for early detection and intervention. Understanding the long-term effects of repetitive head trauma is critical for public health and for shaping policies in sports and military environments.
