Chronic traumatic encephalopathy

Chronic traumatic encephalopathy
Name	Chronic traumatic encephalopathy
Synonyms	CTE, dementia pugilistica, punch-drunk syndrome
Field	Neurology, Psychiatry, Neuropathology
Causes	Repetitive traumatic brain injury
Risks	Contact sports, military combat
Diagnosis	Post-mortem brain examination
Treatment	Symptomatic management

Chronic traumatic encephalopathy. It is a progressive neurodegenerative disease found in individuals with a history of repetitive traumatic brain injury. The condition is characterized by the abnormal accumulation of tau protein in the brain, leading to cognitive, behavioral, and motor impairments. It has been most commonly associated with athletes in contact sports like American football, boxing, and ice hockey, as well as military veterans exposed to blast injury.

Signs and symptoms

Clinical presentation often includes impairments in memory and executive function, alongside mood disturbances such as depression, apathy, and impulsivity. Physical symptoms may progress to include dysarthria, parkinsonism, and gait abnormality. Behavioral changes can involve aggression, paranoia, and suicidal ideation, with symptoms typically manifesting years or decades after the initial injuries. The Boston University CTE Center has documented cases in former athletes from the National Football League and National Hockey League.

Pathophysiology

The primary pathological hallmark is the deposition of hyperphosphorylated tau protein as neurofibrillary tangles around small blood vessels at the depths of cortical sulci. This differs from the distribution seen in Alzheimer's disease. This process is believed to be triggered by repeated axonal injury and subsequent neuroinflammation, leading to progressive brain atrophy. Research from the Veterans Affairs-Boston University-National Institutes of Health brain bank has detailed this unique tauopathy.

Diagnosis

A definitive diagnosis can only be made posthumously through a neuropathological examination of brain tissue. International consensus diagnostic criteria were established by the National Institute of Neurological Disorders and Stroke. Antemortem diagnosis remains challenging, though research is investigating potential biomarkers such as tau PET scan and MRI. The Mayo Clinic and the Cleveland Clinic are among institutions conducting clinical research toward identifying in vivo indicators.

Risk factors

The principal risk factor is exposure to repetitive mild traumatic brain injury, including subconcussive impact. Professions and activities with high exposure include participation in contact sports like boxing, mixed martial arts, and rugby football. Military service, particularly exposure to improvised explosive device blasts, is another significant risk. The duration of athletic career in leagues like the NFL and genetic factors such as the APOE ε4 allele may also influence susceptibility.

Prevention and treatment

As there is no cure, prevention is focused on reducing head trauma exposure through rule changes in sports like the NFL's concussion protocol and improved protective equipment like football helmet technology. Organizations like the Centers for Disease Control and Prevention promote public awareness campaigns. Treatment is solely symptomatic, involving cognitive behavioral therapy, antidepressant medications, and management of movement disorders by specialists in neurology and psychiatry.

History

The condition was first described in 1928 by Harrison Martland as "punch drunk" syndrome in boxers. Later termed dementia pugilistica, it was further characterized by J.A.N. Corsellis in the 1970s. Modern understanding was revolutionized by the work of Bennet Omalu, who published findings on an NFL player in 2005, leading to widespread media attention through films like Concussion (film). The National Football League initially disputed the link before acknowledging the problem and funding research through the National Institutes of Health.

Category:Neurodegenerative disorders Category:Traumatic brain injury Category:Sports injuries